One of the main properties of animal organisms is the ability to adapt to the surrounding world through movement. In the human body, as a reflection of the evolutionary process, 3 types of movement are distinguished: amoeboid movement of blood cells, ciliated movement of the cilia of the epithelium and movement with the help of muscles (as the main one). The bones that make up the skeleton of the body are set in motion by the muscles and together with them and the joints form the musculoskeletal system. This apparatus carries out the movement of the body, support, preservation of its shape and position, and also performs a protective function, limiting the cavities in which the internal organs are placed.
In the musculoskeletal system, two parts are distinguished: passive - bones and their joints and active - striated muscles.
The collection of bones connected by connective, cartilage or bone tissue is called the skeleton (skeletons- dried).
The function of the skeleton is due, on the one hand, to its participation in the work of the musculoskeletal system (the function of levers during movement, support, and protection), and on the other hand, to the biological properties of bone tissue, in particular, its participation in mineral metabolism, hematopoiesis, and regulation of electrolyte balance. .
SKELETON DEVELOPMENT
Most of the human bones go through successive stages of development during embryogenesis: membranous, cartilaginous and bone.
In the early stages, the skeleton of the embryo is represented by the dorsal string, or chord, which arises from mesoderm cells and is located under the neural tube. The notochord exists during the first 2 months of intrauterine development and serves as the basis for the formation of the spine.
From the middle of the 1st month of intrauterine life, clusters of cells around the notochord and neural tube appear in the mesenchyme, which later turn into a spinal column that replaces the notochord. Similar accumulations of mesenchyme are formed in other places, forming the primary skeleton of the embryo - a membranous model of future bones. it membranous (connective tissue) stage skeletal development.
Most of the bones, with the exception of the bones of the cranial vault, face and middle part of the clavicle, go through another - cartilage stage. In this case, the membranous skeleton is replaced by cartilaginous tissue, which develops from the mesenchyme at the 2nd month of intrauterine development. Cells acquire the ability to secrete an intermediate dense substance - chondrin.
On the 6-7th week, bones begin to appear - bone stage skeletal development.
The development of bone from connective tissue is called direct ossification, and such bones primary bones. The formation of bone in place of cartilage is called indirect ossification, and the bones are called secondary. In the embryo and fetus, intensive ossification occurs, and most of the skeleton of the newborn consists of bone tissue. In the postnatal period, the process of ossification slows down and ends by the age of 25-26.
Bone development. The essence of both direct and indirect ossification is the formation of bone tissue from special cells - osteoblasts, mesenchymal derivatives. Osteoblasts produce the intercellular ground substance of bones, in which calcium salts are deposited in the form of hydroxyapatite crystals. In the early stages of development, the bone tissue has a coarse fibrous structure, in later stages it is lamellar. This occurs as a result of the deposition of organic or inorganic matter in the form of plates located concentrically around ingrown vessels and forming primary osteons. As ossification develops, bone crossbars are formed - trabeculae, limiting the cells and contributing to the formation of spongy bone. Osteoblasts turn into bone cells - osteocytes, surrounded by bone. In the process of calcification, gaps remain around osteocytes - tubules and cavities through which vessels pass, which play an important role in bone nutrition. The surface layers of the connective tissue model of the future bone are transformed into the periosteum, which serves as a source of bone growth in thickness (Fig. 12-14).
Rice. 12.Human skull in the 3rd month of development:
1 - frontal bone; 2 - nasal bone; 3 - lacrimal bone; 4 - sphenoid bone; 5 - upper jaw; 6 - zygomatic bone; 7 - ventral cartilage (from the cartilaginous rudiment of the first gill arch); 8 - lower jaw; 9 - styloid process; 10 - drum part temporal bone; 11 - scales of the temporal bone; 12, 16 - parietal bone; 13 - a large wing of the sphenoid bone; 14 - visual channel; 15 - small wing of the sphenoid bone
Rice. 13. Bone development: a - cartilaginous stage;
b - the beginning of ossification: 1 - the point of ossification in the epiphysis of the bone; 2 - bone tissue in the diaphysis; 3 - ingrowth of blood vessels into the bone; 4 - emerging cavity with bone marrow; 5- periosteum
Rice. fourteen.Newborn skeleton:
Along with the formation of bone tissue, opposite processes take place - the destruction and resorption of bone sections, followed by the deposition of new bone tissue. The destruction of bone tissue is carried out by special cells - bone destroyers - osteoclasts. The processes of destruction of bone tissue and its replacement with a new one occur throughout the entire period of development and provide growth and internal restructuring of the bone, as well as a change in its external shape due to changing mechanical effects on the bone.
GENERAL OSTEOLOGY
The human skeleton consists of more than 200 bones, of which about 40 are unpaired, and the rest are paired. The bones make up 1/5-1/7 of the body weight and are divided into the bones of the head - the skull, the bones of the trunk and the bones of the upper and lower extremities.
Bone- an organ consisting of several tissues (bone, cartilage and connective) and having its own vessels and nerves. Each bone has a specific structure, shape, and position inherent only to it.
Bone classification
According to the form, function, structure and development of the bones are divided into groups
(Fig. 15).
1.Long (tubular) bones- these are the bones of the skeleton of the free limbs. They are built from a compact substance located along the periphery and an internal spongy substance. In tubular bones, the diaphysis is distinguished - the middle part containing the bone marrow cavity, the epiphyses - the ends and the metaphysis - the area between the epiphysis and the diaphysis.
2.Short (spongy) bones: bones of the wrist, tarsus. These bones are built of spongy substance surrounded by a thin plate of compact substance.
3.flat bones- bones of the cranial vault, scapula, pelvic bone. In them, the layer of spongy substance is less developed than in spongy bones.
4.Irregular (Mixed) Bones built more complex and combine the features of the structure of the previous groups. These include
Rice. fifteen. Types of human bones:
1 - long (tubular) bone - humerus; 2 - flat bone - scapula; 3 - irregular (mixed) bone - vertebra; 4 - shorter than the first tubular bone - phalanx of fingers
vertebrae, bones of the base of the skull. They are formed from several parts with different development and structure. In addition to these groups of bones, there are
5.air bones, which contain cavities filled with air and lined with mucous membranes. These are the bones of the skull: the upper jaw, frontal, sphenoid and ethmoid bones.
The skeletal system also includes special
6.Sesamoid bones(patella, pisiform bone), located in the thickness of the tendons and helping the muscles work.
Bone relief determined by roughness, furrows, holes, channels, tubercles, processes, dimples. Roughness
and processes are places of attachment to the bones of muscles and ligaments. Tendons, vessels and nerves are located in the channels and furrows. Pinholes on the surface of the bone are the places where the vessels that feed the bone pass through.
Chemical composition bones
The composition of the living bone of an adult includes water (50%), organic substances (28.15%) and inorganic components (21.85%). Fat-free and dried bones contain approximately 2/3 of inorganic substances, represented mainly by calcium, phosphorus and magnesium salts. These salts form complex compounds in the bones, consisting of submicroscopic hydroxyapatite crystals. The organic matter of the bone is collagen fibers, proteins (95%), fats and carbohydrates (5%). These substances give the bones strength and elasticity. The bones contain more than 30 osteotropic microelements, organic acids, enzymes and vitamins. Features of the chemical composition of the bone, the correct orientation of collagen fibers along the long axis of the bone and the peculiar arrangement of hydroxyapatite crystals provide bone tissue with mechanical strength, lightness and physiological activity. The chemical composition of bones depends on age (organic substances predominate in children, inorganic substances in the elderly), the general condition of the body, functional loads, etc. In a number of diseases, the chemical composition of bones changes.
The structure of the bones
Macroscopically, the bone consists of a peripheral compact substance (substantia compacta) and spongy substance (substantia spongiosa)- masses of bone crossbars in the middle of the bone. These crossbars are not arranged randomly, but according to the lines of compression and tension that act on certain areas of the bone. Each bone has a structure that best suits the conditions in which it is located (Fig. 16).
Spongy bones and epiphyses of tubular bones are mainly built from cancellous matter, and diaphyses of tubular bones are built from compact. The medullary cavity, located in the thickness of the tubular bone, is lined with a connective tissue membrane - endosteum.
Rice. 16. Bone structure:
1 - metaphysis; 2 - articular cartilage;
3- spongy substance of the epiphysis;
4- compact substance of the diaphysis;
5- bone marrow cavity in the diaphysis, filled with yellow bone marrow (6); 7 - periosteum
The cells of the spongy substance and the medullary cavity (in the tubular bones) are filled with bone marrow. Distinguish between red and yellow bone marrow (medulla ossium rubra et flava). From the age of 12-18, the red bone marrow in the diaphysis is replaced by yellow.
Outside, the bone is covered with periosteum, and at the junctions with the bones - with articular cartilage.
Periosteum(periosteum)- connective tissue formation, consisting in adults of two layers: internal osteogenic, containing osteoblasts, and external fibrous. The periosteum is rich in blood vessels and nerves that continue into the thickness of the bone. The periosteum is connected to the bone by collagen fibers penetrating into the bone, as well as by vessels and nerves passing from the periosteum to the bone through nutrient channels. The periosteum is the source of bone growth in thickness and is involved in the blood supply to the bone. Due to the periosteum, the bone is restored after a fracture. With age, the structure of the periosteum changes and its bone-forming abilities weaken, so bone fractures in old age heal for a long time.
Microscopically, the bone consists of bone plates arranged in a certain order. These plates are formed by collagen fibers impregnated with the basic substance and bone cells: osteoblasts, osteoclasts and osteocytes. The plates have thin tubules through which arteries, veins and nerves pass.
Bone plates are divided into common, covering the bone from the outer surface (outer plates) and from the side of the medullary cavity (inner plates) on the osteon plates, located concentrically around the blood vessels, and interstitial, located between osteons. Osteon is a structural unit of bone tissue. It is represented by 5-20 bone cylinders inserted one into the other and limiting the central canal of the osteon. In addition to osteon channels, bones secrete perforating nutritious channels, which connect osteon channels (Fig. 17).
The bone is an organ, the external and internal structure of which is subject to change and renewal throughout a person’s life in accordance with the changing conditions of life. Bone remodeling occurs as a result of interrelated processes destruction and creation, providing high plasticity and reactivity of the skeleton. The processes of formation and destruction of bone substance are regulated by the nervous and endocrine systems.
child's living conditions, past illnesses, the constitutional features of his body affect the development of the skeleton. Sports, physical labor stimulate the restructuring of the bone. Bones that are under heavy load undergo restructuring, leading to a thickening of the compact layer.
Blood supply and innervation of bones. The blood supply to the bones is carried out from the arteries and branches of the arteries of the periosteum. Arterial branches penetrate through the nutrient holes in the bones and divide sequentially to the capillaries. Veins accompany arteries. The branches of the nearest nerves approach the bones, forming the nerve plexus in the periosteum. One part of the fibers of this plexus ends in the periosteum, the other, accompanying the blood
Rice. 17. Bone microstructure:
1 - periosteum (two layers); 2 - compact substance, consisting of osteons; 3 - spongy substance from the crossbars (trabeculae) lined over the bone by the endosteum; four - bone plates that form the osteon; 5 - one of the osteons; 6 - bone cells - osteocytes; 7 - blood vessels passing inside the osteons
nasal vessels, passes through the nutrient channels of the osteons and reaches the bone marrow.
Questions for self-control
1. List the main functions of the skeleton.
2. What stages of development of human bones in the process of embryogenesis do you know?
3. What is perichondral and endochondral ossification? Give an example.
4. What groups are bones classified according to their shape, function, structure and development?
5. What organic and inorganic substances are included in the composition of the bone?
6. What connective tissue formation covers the outside of the bone? What is its function?
7. What is the structural unit of bone tissue? What is it represented by?
TRUNK BONES
Body bone development
The bones of the trunk develop from sclerotomes - the ventromedial part of the somites. The rudiment of the body of each vertebra is formed from the halves of two adjacent sclerotomes and lies in the intervals between two adjacent myotomes. Accumulations of mesenchyme spread from the center of the vertebral body in the dorsal and ventral directions, forming the beginnings of the arches of the vertebrae and ribs. This stage of bone development, as noted earlier, is called membranous.
The replacement of mesenchymal tissue with cartilage occurs through the formation of separate cartilaginous centers in the vertebral body, in the arch and rudiments of the ribs. At the 4th month of fetal development, a cartilaginous vertebra and ribs are formed.
The anterior ends of the ribs fuse with the paired rudiments of the sternum. Later, by the 9th week, they grow together along the midline, forming the sternum.
vertebral column
vertebral column(columna vertebralis) is a mechanical support of the whole body and consists of 32-34 interconnected vertebrae. It has 5 departments:
1) cervical of 7 vertebrae;
2) thoracic of 12 vertebrae;
3) lumbar of 5 vertebrae;
4) sacral of 5 fused vertebrae;
5) coccygeal of 3-5 fused vertebrae; 24 vertebrae are free - true and 8-10 - false, fused together into two bones: the sacrum and the coccyx (Fig. 18).
Each vertebra has body (corpus vertebrae), facing forward; arc (arcus vertebrae), which, together with the body, limits vertebral foramen (for. vertebrale), representing in aggregate spinal canal. The spinal cord is located in the spinal canal. Processes depart from the arc: unpaired spinous process turned backwards; two transverse processes (processus transversus); paired upper and lower articular processes (processus articulares superior et inferior) have a vertical direction.
At the junction of the arc with the body, there are upper and lower vertebral notches that limit the intervertebral foramens in the spinal column. (forr. intervertebralia), where nerves and blood vessels pass. The vertebrae of different departments have characteristic features that make it possible to distinguish them from each other. The size of the vertebrae increases from the cervical to the sacral due to a corresponding increase in the load.
Cervical vertebrae(vertebrae cervicales) have a cross hole (for. transversarium), the spinous process of the II-V vertebrae is bifurcated, the body is small, oval in shape. In the openings of the transverse processes, the vertebral arteries and veins pass, supplying blood to the brain and spinal cord. At the ends of the transverse processes of the VI cervical vertebra, the anterior tubercle is called the carotid, and the carotid artery can be pressed against it to stop bleeding from its branches. The spinous process of the VII cervical vertebra is longer, it is well palpable and is called a protruding vertebra. I and II cervical vertebrae have a special structure.
The first(C I) cervical vertebra- atlas(atlas) has anterior and posterior arches of the atlas (arcus anterior atlantis et arcus posterior atlantis), two
Rice. 18.1. Vertebral column: a - side view; b - rear view
Rice. 18.2. Two upper cervical vertebrae:
a - the first cervical vertebra-atlas, top view: 1 - transverse opening on the transverse process; 2 - anterior arch of the atlas; 3 - anterior tubercle; 4 - tooth fossa;
5- lateral mass with upper articular surface (6); 7 - posterior tubercle; 8 - rear arc; 9 - groove of the vertebral artery;
b - second cervical vertebra - axial or axis, rear view: 1 - lower articular process; 2 - body of the axial vertebra; 3 - tooth; 4 - posterior articular surface; 5 - upper articular surface; 6 - transverse process with the opening of the same name; 7 - spinous process
Rice. 18.3. Seventh cervical vertebra, top view:
1 - arch of the vertebra; 2 - transverse process with a transverse hole (3); 4 - vertebral body; 5 - upper articular surface; 6 - vertebral foramen; 7 - spinous process (the longest of the cervical vertebrae)
Rice. 18.4. Thoracic vertebra, side view:
1 - vertebral body; 2 - upper costal fossa; 3 - upper articular process; 4 - arch of the vertebra; 5 - transverse process with a costal fossa (6); 7 - spinous process; 8 - lower articular process; 9 - lower costal fossa
Rice. 18.5. Lumbar vertebrae:
a - view of the lumbar vertebra from above: 1 - mastoid; 2 - upper articular process; 3 - transverse process; 4 - vertebral body; 5 - vertebral foramen; 6 - arch of the vertebra; 7 - spinous process;
b - lumbar vertebrae, side view: 1 - intervertebral disc connecting the vertebral bodies; 2 - upper articular process; 3 - mastoid process; 4 - lower articular process; 5 - intervertebral foramen
Rice. 18.6. sacrum and coccyx:
a - front view: 1 - superior articular process; 2 - sacral wing; 3 - lateral part; 4 - transverse lines; 5 - sacrococcygeal joint; 6 - coccyx [coccygeal vertebrae Co I -Co IV]; 7 - top of the sacrum; 8 - anterior sacral openings; 9 - cape; 10 - the base of the sacrum;
b - rear view: 1 - superior articular process; 2 - tuberosity of the sacrum; 3 - ear-shaped surface; 4 - lateral sacral crest; 5 - median sacral crest; 6 - medial sacral crest; 7 - sacral fissure; 8 - sacral horn; 9 - sacrococcygeal joint; 10 - coccyx [coccygeal vertebrae Co I -Co IV]; 11- coccygeal horn; 12 - rear sacral openings; 13 - lateral part; 14 - sacral canal
lateral masses (massa lateralis atlantis) and transverse processes with holes. The anterior tubercle stands out on the outer surface of the anterior arch (tuberculum anterius), on the inside - the fossa of the tooth (fovea dentis). The posterior tubercle is well defined on the outer surface of the posterior arch. Each lateral (lateral) mass has articular surfaces: on the upper surface - the upper, on the lower - the lower.
The axial vertebra (axis) (C II) differs from other vertebrae in that its body continues into a process - a tooth (dens), having anterior and posterior articular surfaces.
Thoracic vertebrae(vertebrae thoracicae), unlike other vertebrae, they have two costal fossae on the lateral surfaces of the body - upper and lower (foveae costales superior et inferior). On each transverse process of the I-X vertebrae there is a costal fossa of the transverse process (fovea costalis processus transversis) for articulation with ribs. The exception is I, X-XII vertebrae. On the I vertebra at the upper edge of the body there is a complete fossa, the X vertebra has only the upper half-fossa, and the XI and XII have one full fossa each in the middle of the body.
Lumbar vertebrae(vertebrae lumbales), the most massive, together with the sacral vertebrae, take the main load on the spinal column. Their articular processes are located sagittally, on the upper articular processes there are mastoid processes. (processus mammilares). The spinous processes have a horizontal direction.
sacrum, sacral vertebrae(vertebrae s acrales) in adults, fuse into one bone - sacrum (sacral vertebrae I-V)(os sacrum); (vertebrae sacrales I-V). Distinguish the base of the sacrum (basis ossis sacri), upward, top (apex ossis sacri) downward, and the lateral parts (partes lalerales). The anterior surface of the sacrum is concave into the pelvic cavity, the posterior surface is convex and has a number of ridges. On the anterior pelvic surface (facies pelvica) there are 4 paired anterior sacral foramen (forr. sacralia anteriora), connected by cross lines (lineae transversae), traces of fusion of the bodies of the sacral vertebrae. On the dorsal (back) surface (facies dorsalis)- also 4 pairs of posterior sacral foramen (forr. sacralia posterior).
On the dorsal surface of the sacrum there are 5 sacral crests: unpaired median (crista sacralis mediana), paired medial
ny (crista sacralis medialis) and lateral (crista sacralis lateralis). They are respectively fused spinous, articular and transverse processes. In the lateral parts of the sacrum, the ear-shaped surface is isolated (facies auricularis) and sacral tuberosity (tuberositas ossis sacri), serving to connect with the pelvic bone. The base of the sacrum is connected to the V lumbar vertebra at an angle to form a cape, promontory, which protrudes into the pelvic cavity.
Coccyx(os coccygis)- a small bone resulting from the fusion of 3-5 rudimentary vertebrae. The most developed is the 1st coccygeal vertebra, which has the remains of articular processes - coccygeal horns (cornua coccygeum), connecting with the sacral horns.
Skeleton chest
To skeleton of the chest(skeleton thoracis) includes the sternum and ribs.
Sternum(sternum)- unpaired flat bone. It distinguishes the handle (manubrium sterni), body (corpus sterni), xiphoid process (processus xiphoideus) and clippings: on the upper edge of the handle there is an unpaired jugular notch (incisura jugularis) and paired clavicular notch (incisura clavicularis), on the lateral surfaces of the sternum - 7 costal notches each (incisurae costales).
Ribs (I-XII)(costae) are made up of bone and cartilage. The costal cartilage is the anterior part of the rib, which connects to the sternum at the 7 upper ribs. Distinguish true ribs(I-VII) (costae verae)false edges(VIII-X) (costae spuriae) and freely ending in the thickness of the anterior abdominal wall oscillating ribs(XI and XII) (costae fluctuantes). In the bony part of the rib, a head is isolated (caput costae). The head of the rib passes into the narrow part - the neck (collum costae), and the neck - into the wide and long part of the costal bone - the body of the rib (corpus costae). At the point of transition of the neck into the body of the rib, an angle of the rib is formed (angulus costae). Here is the tubercle of the rib (tuberculum costae) with an articular surface for connection with the transverse process of the corresponding vertebra. On the body, the ribs distinguish between the outer and inner surfaces.
On the inner surface along the lower edge there is a groove of the rib (sul. costae)- a trace from adjacent vessels and nerves.
Some structural features have the first rib and the last 2 ribs. On the 1st rib, the upper and lower surfaces, the inner and outer edges are distinguished. On the upper surface there is a tubercle of the anterior scalene muscle (tuberculum m. scaleni anterioris), separating the groove of the subclavian vein (in front) from the groove of the subclavian artery. XI and XII ribs do not have a neck, angle, tubercle, furrow, scallop on the head.
Differences and anomalies in the structure of the bones of the body
The number of calls may vary. Thus, there may be 6 cervical vertebrae due to the assimilation of VII into the I thoracic and an increase in the number of thoracic vertebrae and ribs. Sometimes the number of thoracic vertebrae and ribs decreases to 11. Sacralization is possible - the V lumbar vertebra grows to the sacrum and lumbarization - the separation of the I sacral vertebra. There are frequent cases of splitting of the vertebral arch, which is possible in various parts of the spine, especially often in the lumbar (spina bifida). There are splitting of the sternum, the anterior end of the ribs, and additional cervical and lumbar ribs.
Age, individual and gender differences relate to the shape and position of bones, cartilage layers between individual parts of the bone.
Questions for self-control
1.Which departments spinal column do you know?
2. What are the differences between the I and II cervical vertebrae and the rest of the vertebrae?
3. List features cervical, thoracic, lumbar vertebrae and sacrum.
4. What cuts are on the sternum and what are they for?
5. How many ribs does a person have and what are their features?
6. What anomalies do you know in the structure of the bones of the body?
LIMB BONES
There is much in common in the structure of the bones of the upper and lower extremities. Distinguish between the skeleton of the belt and the skeleton of the free limb, consisting of the proximal, middle and distal sections.
Differences in the structure of the bones of the upper and lower extremities are due to the difference in their functions: the upper limbs are adapted to perform various and subtle movements, the lower ones - for support during movement. The bones of the lower limb are large, the belt lower limb sedentary. The girdle of the upper limb is movable, the bones are smaller.
Development of limb bones
The rudiments of the skeleton of the upper and lower limbs appear on the 4th week of intrauterine development.
All bones of the limbs go through 3 stages of development, and only the clavicle - two: membranous and bone.
Upper limb bones(ossa membri superioris)
Upper limb belt
Upper limb belt (Cingulum membri superioris) consists of the scapula and collarbone (Fig. 19).
shoulder blade(scapula)- a flat bone in which the costal (anterior) and posterior surfaces are distinguished (facies costalis (anterior) et posterior), 3 edges: medial (margo medialis) upper (margo superior) with blade notch (Incisura scapulae) and lateral (margo lateralis); 3 corners: bottom (angulus inferior) upper (angulus superior) and lateral (angulus lateralis), socketed (cavitas glenoidalis). The articular cavity is separated from the scapula by the neck (collum scapulae). Above and below the articular cavity are supra-articular and sub-articular tubercles (tuberculum supraet infraglenoidale). Above the lateral angle are the coracoid process (processus coracoideus) and acromion, continuing into the scapular spine, separating the supraspinatus and infraspinatus fossae. The costal surface of the scapula is concave and is called the subscapular fossa (fossa subscapularis).
Collarbone(clavicula)- a curved tubular bone in which the body is isolated (corpus claviculae) and 2 ends: sternal (extremitas sternalis) and acromial (extremitas acromialis). The sternal end is expanded, has an articular surface for connection with the sternum; the acromial end is flattened and connects to the acromion of the scapula.
Rice. 19. Bones of the upper limb, right, front view: 1 - clavicle; 2 - sternal end of the clavicle; 3 - scapula; 4 - coracoid process of the scapula; 5 - articular cavity of the scapula; 6 - humerus;
7- coronal fossa humerus;
8- medial epicondyle; 9 - block of the humerus; 10 - coronoid process; 11 - tuberosity of the ulna; 12 - elbow bone; 13 - head of the ulna; 14 - bones of the wrist; fifteen - I-V metacarpals bones; 16 - phalanges of fingers; 17 - styloid process of the radius; 18 - radius; 19 - head of the radius; 20 - crest of a large tubercle; 21 - intertubercular furrow; 22 - large tubercle; 23 - small tubercle; 24 - head of the humerus; 25 - acromion
Rice. twenty. Humerus, right, posterior view:
1 - block of the humerus; 2 - groove of the ulnar nerve; 3 - medial epicondyle; 4 - medial edge of the humerus; 5 - body of the humerus; 6 - head of the humerus; 7 - anatomical neck; 8 - large tubercle; 9 - surgical neck; 10 - deltoid tuberosity; 11 - groove of the radial nerve; 12 - lateral edge; 13 - fossa of the olecranon; 14 - lateral epicondyle
Free part of the upper limb
Free upper limb (pars libera membri superioris) consists of 3 sections: proximal - shoulder (brachium), middle - forearm (antebracium) and distal - brushes (manus). The skeleton of the shoulder is the humerus.
Brachial bone(humerus)- a long tubular bone, in which a body is distinguished - the diaphysis and 2 ends - the proximal and distal epiphyses (Fig. 20).
The upper end of the humerus is thickened and forms a head (caput humeri) which is separated from the rest of the bone by the anatomical neck (collum anatomicum). Immediately behind the anatomical neck are 2 tubercles - large and small (tuberculum majus et minus), continuing downward into ridges, separated by an intertubercular furrow (suclus intertubercularis).
At the point of transition of the upper end of the humerus into the body is the surgical neck (collum chirurgicum)(fractures often occur here), and in the middle of the body of the bone - deltoid tuberosity (tuberositas deltoidea).
Behind the tuberosity is the groove of the radial nerve (sul. n. radialis). Lower humerus - condyle (condylus humeri). Its lateral sections form the medial and lateral
epicondyle Behind the medial epicondyle is the sulcus of the ulnar nerve (sul. n. ulnaris). On the basis of the lower end of the humerus are the block of the humerus (trochlea humeri), for articulation with ulna, and the head of the condyle of the humerus (capitulum humeri), for articulation with the radius. Under the block on the posterior surface of the lower end of the bone is the fossa of the olecranon (fossa olecrani), on the anterior surface - coronal (fossa coronoidea).
Bones of the forearm. The skeleton of the forearm consists of 2 tubular bones: the ulna, located on the medial side, and the radius, located laterally (Fig. 21).
Elbow bone(ulna) in the region of the proximal epiphysis it has 2 processes: the upper ulnar (olecranon) and inferior coronal (processus coronoideus), that limit the block cut (incisura trochlearis). On the lateral side of the coronoid process there is a radial notch (incisura radialis), and below and behind - tuberosity (tuberositas ulnae). The distal epiphysis has a head, on the medial side of which the styloid process of the ulna extends (processus styloideus ulnae).
Rice. 21. Ulna and radius of the right forearm, rear view: 1 - olecranon; 2 - head of the radius; 3 - articular circumference; 4 - neck of the radius; 5 - tuberosity of the radius; 6- radius; 7 - lateral surface; 8 - rear surface; 9 - rear edge; 10 - styloid process of the radius; 11 - styloid process of the ulna; 12 - rear surface; 13 - medial surface; 14 - trailing edge; 15 - ulna; 16 - coronoid process
Radius(radius) has a head (proximal epiphysis), equipped at the top with a flat fossa for articulation with the humerus, on the lateral surface - an articular circumference for articulation with the ulna. Below the head there is a neck, below and medial to which there is a tuberosity (tuberositas radii). The distal epiphysis is thickened, on the lateral side it has a styloid process and a carpal articular surface.
Hand bones(ossa manus) include the bones of the wrist, metacarpal bones and phalanges of the fingers (Fig. 22).
wrist bones(ossa carpi, ossa carpalia) consist of 8 small bones arranged in 2 rows. The composition of the proximal row includes (counting from the side of the thumb) the navicular bone (os scaphoideum), semilunar (os lunatum) trihedral (os triquetrum) and pisiform (os pisiforme).
The distal row includes the trapezoid bone (os trapezium), trapezoidal (os trapezoideum), capitate (os capitatum) and hooked (os hamatum). The bones of the wrist have articular surfaces for connection with each other and with neighboring bones.
metacarpal bones(ossa metacarpi, ossa metacarpalia) consist of 5 metacarpal bones (I-V), each of which has a body, a base (proximal end) for connection with the second row of carpal bones, and a head (distal end). The articular surfaces of the bases of the II-V metacarpal bones are flat, those of the I bone are saddle-shaped.
Finger bones(ossa digitorum);phalanx(phalanges). The first (I) finger has 2 phalanges - proximal and distal, the rest - 3 each: proximal, middle and distal. Each phalanx (phalanges) has a body, the proximal end is the base and the distal end is the head.
Differences in the structure of the bones of the upper limb
The individual characteristics of the clavicle are expressed in different lengths and various curvature.
The shape and size of the scapula are also variable. In women, the shoulder blade is thinner than in men; in 70% of right-handed people, the right shoulder blade is larger than the left. Individual differences in the humerus relate to its size, shape, degree of twisting - turning the lower epiphysis outward in relation to the upper one. One of the bones of the forearm, often the radius, may be absent. Both bones may be fused throughout.
Rice. 22. Bones of the hand, front view:
1 - trapezoid bone; 2 - trapezoid bone; 3 - navicular bone; 4 - lunate bone; 5 - trihedral bone; 6 - pisiform bone; 7 - hook-shaped bone; 8 - bones of the metacarpus; 9 - phalanges of fingers; 10 - capitate bone
Questions for self-control
1. What bones belong to the girdle of the upper limb and parts of the free upper limb?
2. Name the bones that make up the proximal and distal rows of the carpal bones.
3. List the articular surfaces of the bones of the shoulder and forearm. What are they for?
Bones of the lower limb(ossa membri inferioris)
Lower limb belt
Lower limb belt (Cingulum membri inferioris) represented by paired pelvic bones. In front they connect with each other, behind - with the sacrum, forming a bone ring - the pelvis, a receptacle for the pelvic organs and a support for the trunk and lower extremities (Fig. 23).
Pelvic bone(os sohae)(Fig. 24) consists of 3 fused bones: ilium, pubis and ischium. Until the age of 14-17, they are connected through cartilage.
The bodies of these three bones form the acetabulum (acetabulum)- junction with the head of the femur. The acetabulum is bounded by an edge that is interrupted at the bottom by a notch (incisura acetabuli). Bottom - fossa of the acetabulum (fossa acetabuli) circumferentially bounded by the articular semilunar surface (facies lunata).
Ilium(os tlium) consists of a body (corpus ossis ilii) and wings (ala ossis ilii), separated from each other on the inner surface of the bone by an arcuate line (linea arcuata). The iliac wing is a wide bone plate, fan-shaped expanding upwards and ending with a thickened edge - the iliac crest (crista iliaca). Anteriorly on the crest is the superior anterior iliac spine (spina iliaca anterior superior), behind - superior posterior iliac spine (spina iliaca posterior superior).
Below the superior anterior and posterior spines is the inferior anterior iliac spine. (spina iliaca anterior inferior) and inferior posterior iliac spine (spina iliaca posterior inferior). The iliac spines are sites of attachment for muscles and ligaments.
The 3 broad muscles of the anterior abdominal wall are attached to the iliac crest. The inner surface in the anterior section is concave and
Rice. 23. Bones of the lower limb, front view:
1 - sacrum; 2 - sacroiliac joint; 3 - the upper branch of the pubic bone; 4 - symphysial surface of the pubic bone; 5 - lower branch of the pubic bone; 6 - branch of the ischium; 7 - ischial tubercle; 8 - body of the ischium; 9 - medial epicondyle of the femur; 10 - medial condyle tibia; 11 - tuberosity of the tibia; 12 - body of the tibia; 13 - medial malleolus; 14 - phalanges of fingers; 15 - bones of the metatarsus; 16 - bones of the tarsus; 17 - lateral ankle; 18 - fibula; 19 - the anterior edge of the tibia; 20 - head of the fibula; 21 - lateral condyle of the tibia; 22 - lateral epicondyle of the femur; 23 - patella; 24 - femur;
25 - greater trochanter of the femur;
26 - neck of the femur; 27 - head of the femur; 28 - wing of the ilium; 29 - iliac crest
Rice. 24. Pelvic bone, right: a - outer surface: 1 - ilium; 2 - outer lip; 3 - intermediate line; 4 - inner lip; 5 - anterior gluteal line; 6 - superior anterior iliac spine; 7 - lower gluteal line; 8 - lower anterior iliac spine; 9 - lunar surface; 10 - obturator ridge;
11 - lower branch of the pubic bone;
12- obturator groove; 13 - acetabular notch; 14 - obturator opening; 15 - branch of the ischium; 16 - body of the ischium; 17 - ischial tubercle; 18 - small sciatic notch; 19 - ischial spine; 20 - acetabular fossa;
21 - large sciatic notch;
22 - posterior lower ischial spine; 23 - posterior upper ischial spine;
b - inner surface: 1 - iliac crest; 2 - iliac fossa; 3 - arcuate line; 4 - iliac tuberosity; 5 - ear-shaped surface; 6 - large sciatic notch; 7 - ischial spine; 8 - small sciatic notch; 9 - body of the ischium; 10 - branch of the ischium; 11 - obturator opening; 12 - lower branch of the pubic bone; 13 - symphysial surface; 14 - the upper branch of the pubic bone; 15 - pubic tubercle; 16 - crest of the pubic bone; 17 - iliac-pubic eminence; 18 - lower anterior iliac spine; 19 - superior anterior iliac spine
forms the iliac fossa (fossa iliaca), and behind passes into the ear-shaped surface (facies auricularis), connecting with the corresponding surface of the sacrum. Behind the ear-shaped surface is the iliac tuberosity (tuberositas iliaca) for attaching ties. On the outer surface of the iliac wing there are 3 rough gluteal lines for attaching the gluteal muscles: the lower (linea glutea inferior), anterior (linea glutea anterior) and back (linea glutea posterior).
On the border between the iliac and pubic bones there is an iliopubic eminence (eminentia iliopubica).
Ischium(os ischii) located downward from the acetabulum, has a body (corpus ossis ischii) and branch (r. ossis ischi). The body is involved in the formation of the acetabulum, and the branch is connected to the lower branch of the pubic bone. On the posterior edge of the body is a bony protrusion - the ischial spine (spina ischiadica), which separates the greater ischial notch (incisura ischiadica major) from small (incisura ischiadica minor). At the point of transition of the body to the branch is the ischial tuberosity (tuber ischiadica).
Pubic bone(os pubis) has a body (corpus ossis pubis), upper and lower branches (rr. superior et inferior os pubis). The body makes up the lateral part of the bone and participates in the formation of the acetabulum. Medially, the bone faces the corresponding bone of the opposite side and is provided with a symphysial surface. (facies symphysialis). On the upper surface of the superior branch is the crest of the pubic bone (pecten ossis pubis), which ends anteriorly and medially with the pubic tubercle (tuberculum pubicum).
Free part of the lower limb
Free lower limb (pars libera membri inferioris) consists of 3 sections: proximal - thigh, middle - lower leg and distal - foot.
The skeleton of the thigh is femur(femur)(Fig. 25).
This is the longest tubular bone of the skeleton. It distinguishes the body, proximal and distal epiphyses. The upper, proximal epiphysis has a head (caput femoris) connecting with the acetabulum of the pelvic bone; at the junction, the head is covered with hyaline cartilage. The fossa of the femoral head is located on the head (fovea capitis femoris), which is the site of attachment of the ligament of the femoral head. Below the head is the neck of the femur (collum femoris).
On the border of the neck and body of the femur there are 2 protrusions - skewers, large and small (trochanter major et minor). The greater trochanter is located laterally. The lesser trochanter is located lower and more medially. In front, the skewers are connected by an intertrochanteric line (linea intertrochanterica), behind - intertrochanteric crest (crista intertrochanterica).
The body of the femur is smooth anteriorly, with a rough line posteriorly. (linea aspera). It distinguishes the medial lip (labium mediate), passing at the top into the intertrochanteric line, and the lateral lip (labium laterale), ending superiorly with gluteal tuberosity (tuberositas glutea). At the bottom, the lips diverge, limiting the triangular shape of the popliteal surface (facies poplitea).
The lower, distal epiphysis is expanded and is represented by the medial and lateral condyles (condyli medialis et lateralis). The lateral sections of the condyles have rough protrusions - copper-
Rice. 25. Femur, right, posterior surface:
I - fossa of the femoral head; 2 - head of the femur; 3 - neck of the femur; 4 - large skewer; 5 - intertrochanteric crest; 6 - small spit; 7 - comb line; 8 - gluteal tuberosity;
9 - medial lip of a rough line;
10 - lateral lip of rough line;
II - body of the femur; 12 - popliteal surface; 13 - lateral epicondyle; 14 - lateral condyle; 15 - intercondylar fossa; 16 - medial condyle; 17 - medial epicondyle; 18 - adductor tubercle
al and lateral epicondyles (epicondyli medialis et lateralis). Both condyles are covered with cartilage, which passes from one condyle to the other in front, forming the patella surface (facies patellaris), to which the patella is attached.
Patella(patella)- sesamoid bone that develops in the tendon of the quadriceps femoris muscle. It increases the leverage of this muscle and protects the knee joint from the front.
Lower leg bones represented by the tibia (located medially) and fibula (Fig. 26).
Tibia(tibia) has a body and expanded cones - epiphyses. In the proximal epiphysis, the medial and lateral condyles are distinguished (condyli medialis et lateralis), the upper articular surface of which is connected to the articular surface of the femoral condyles. The articular surfaces of the condyles are divided
Rice. 26. Tibia and fibula, rear view: 1 - condylar eminence; 2 - peroneal articular surface; 3 - nutrient hole; 4 - rear surface; 5 - body of the tibia; 6 - medial malleolus; 7 - ankle groove; 8 - medial edge; 9 - line of the soleus muscle; 10 - top of the head of the fibula; 11 - head of the fibula; 12 - rear edge; 13 - rear surface; 14 - nutrient hole; 15 - lateral surface; 16 - lateral ankle; 17 - medial crest
intercondylar eminence (eminentia intercondylaris), in front and behind of which are the intercondylar fields - the places of attachment of the ligaments. The peroneal articular surface is located on the posterior inferior surface of the lateral condyle. (facies articularis fibularis), necessary for connection with the head of the fibula.
The distal epiphysis is quadrangular in shape, forming the medial medial malleolus (malleolus medialis), and laterally - peroneal notch (incisura fibularis) for the fibula. On the body in front there is a tuberosity of the tibia (tuberositas tibiae)- site of attachment of the tendon of the quadriceps femoris.
Fibula(fibula) thin, expanded upwards in the form of a head (caput fibulae), and below it is extended into the lateral malleolus (malleolus lateralis) for connection with the talus.
Foot bones(ossa pedis)(Fig. 27) include 3 sections: tarsus, metatarsus and fingers. Tarsal bones (ossa tarsi, ossa tarsalia) include 7 spongy bones, forming 2 rows - proximal (talus and calcaneus) and distal (scaphoid, cuboid and 3 cuneiform).
Rice. 27. Bones of the foot, right, top view:
1 - calcaneus; 2 - block of the talus; 3 - talus; 4 - navicular bone; 5 - medial sphenoid bone; 6 - intermediate sphenoid bone; 7 - I metatarsal bone; 8 - proximal phalanx; 9 - distal (nail) phalanx; 10 - middle phalanx; 11 - tuberosity of the V metatarsal bone; 12 - cuboid; 13 - lateral sphenoid bone; 14 - calcaneal tubercle
Talus(talus) is the link between the bones of the lower leg and the rest of the bones of the foot. It releases the body (corpus tali), neck (collum tali), and head (caput tali). The body above and on the sides has articular surfaces for articulation with the tibia.
Calcaneus(calcaneus) has a calcaneal tuberosity (tuber calcanei).
Scaphoid(os naviculare) lies on the medial side of the foot and connects in front with three sphenoid, and behind - with the talus.
Cuboid(os cuboideum) located on the lateral side and connected to the IV and V metatarsal bones, behind - from the calcaneus, and from the medial side - to the lateral sphenoid bone.
Sphenoid bones: medial, intermediate and lateral (os cuneiforme mediale, intermedium et laterale)- located between scaphoid and the bases of the first 3 metatarsal bones.
metatarsal bones(ossa metatarsi; ossa metatarsalia) consist of 5 (I-V) tubular bones having a base, body and head. The articular surfaces of the base are connected to the bones of the tarsus and to each other, the head - to the corresponding phalanx of the fingers.
Finger bones; phalanx(ossa digitorum; phalanges) represented by phalanges (phalanges). The first toe has 2 phalanges, the rest - 3 each. There are proximal, middle and distal phalanges. The bones of the foot are not located in the same plane, but in the form of an arc, forming a longitudinal and transverse arches, which provides a springy support for the lower limb. The foot rests on the ground at several points: the tubercle of the calcaneus and the heads of the metatarsal bones, mainly I and V. The phalanges of the fingers only slightly touch the ground.
Differences in the structure of the bones of the lower limb
The pelvic bone has pronounced gender differences. In women, the upper branch of the pubic bone is longer than in men, the wings of the ilium and ischial tuberosities are turned outward, and in men they are located more vertically.
The acetabulum may be underdeveloped, which causes congenital dislocation of the hip.
The femur varies in length, degree of bending and twisting of the shaft. In old people, the bone marrow cavity of the body of the femur increases, the angle between the neck and body decreases, the head
bones flatten and as a result, the overall length of the lower limbs decreases.
Of the bones of the lower leg, the tibia has the greatest individual differences: its size, shape, cross section of the diaphysis and the degree of its twisting are different. Very rarely, one of the bones of the lower leg is missing.
Additional bones are found in the foot, as well as splitting of some bones; there may be additional fingers - one or two.
X-ray anatomy of the bones of the trunk and limbs
X-rays allow us to examine the bones of a living person, evaluate their shape, size, internal structure, number and location of ossification points. Knowledge of X-ray anatomy of bones helps to distinguish the norm from the pathology of the skeleton.
For X-ray examination of the vertebrae, separate images (radiographs) of the cervical, thoracic, lumbar, sacral and coccygeal regions are taken in the lateral and anteroposterior projections, and, if necessary, in other projections. On radiographs
Rice. 28. X-ray of the humerus, mediolateral (lateral) projection: 1 - clavicle; 2 - coracoid process; 3 - acromial process of the scapula; 4 - articular cavity of the scapula; 5 - head of the humerus; 6 - surgical neck of the humerus; 7 - diaphysis of the humerus; 8 - coronal fossa of the humerus; 9 - superposition image of the head of the condyle and block of the humerus; 10 - fossa of the ulnar process of the humerus; 11 - radius; 12 - ulna (according to A.Yu. Vasiliev)
vertebrae in the lateral projection bodies, arcs, spinous processes are visible (ribs are projected on the thoracic vertebrae); the transverse processes are projected (superimposed) on the bodies and pedicles of the vertebral arches. On the pictures in the anteroposterior projection, it is possible to determine the transverse processes, the bodies onto which the arches and spinous processes are projected.
On radiographs of the bones of the upper and lower extremities in the anteroposterior and lateral projections, the details of their relief, as well as the internal structure (compact and spongy substance, cavities in the diaphysis), discussed in the previous sections of the textbook, are determined. If the x-ray beam successively passes through several bone structures, then their shadows are superimposed on each other (Fig. 28).
It should be borne in mind that in newborns and children, due to incomplete ossification, some bones may be presented in fragments. In persons of adolescence (13-16 years) and even youth (17-21 years) age, stripes corresponding to epiphyseal cartilages are observed in the epiphyses of long bones.
Roentgenograms of the skeleton, in particular the hand, consisting of many bones with different periods of ossification, serve as objects for determining the age of a person in anthropology and forensic medicine.
Questions for self-control
1. What bones belong to the girdle of the lower limb and parts of the free lower limb?
2. List the protrusions (bumps, lines) on the bones of the lower limb, which serve as the place of origin and attachment of muscles.
3. What articular surfaces of the bones of the lower limb do you know? What are they for?
4. How many bones are in the foot? What are these bones?
5. In what projections on radiographs are the bones of the upper and lower extremities clearly visible?
BRIEF INFORMATION ABOUT THE SKULL BONES
Scull(cranium) is the skeleton of the head. It has two departments, different in development and functions: cerebral skull(neurocranium) and facial skull(viscerocranium). The first one forms a cavity for
the brain and some sense organs, the second forms the initial parts of the digestive and respiratory systems.
In the brain skull distinguish vault of the skull(calvaria) and below base(basis cranii).
The skull is not a single monolithic bone, but is formed by various types of joints from 23 bones, some of which are paired (Fig. 29-31).
Bones of the brain skull
Occipital bone(os occipitale) unpaired, located behind. It distinguishes basilar part, 2 lateral parts and scales. All these parts limit the big hole (for. magnum), through which the spinal cord connects to the brain.
Parietal bone(os parietale) steam room, located anterior to the occipital, has the form of a quadrangular plate.
frontal bone(os frontale) unpaired, placed in front of other bones. It has 2 eye parts, forming the upper wall of the orbit, frontal scales and nasal part. Inside the bone is a cavity - frontal sinus (sinus frontalis).
Ethmoid bone(os ethmoidals) unpaired, located between the bones of the brain skull. Consists of a horizontal cribriform plate upwards from it cockscomb, going down perpendicular plate and the most massive part - lattice labyrinth, built from numerous lattice cells. Leaving the maze upper and middle turbinate, as well as hook-shaped process.
Temporal bone(os temporal) steam room, the most complex of all the bones of the skull. It contains the structures of the outer, middle and inner ear, important vessels and nerves. There are 3 parts to the bone: scaly, pyramid (stony) and drum. On the scaly part there is zygomatic process and mandibular fossa, involved in the formation of the temporomandibular joint. In the pyramid (stony part) there are 3 surfaces: front, back and bottom, on which there are numerous holes and grooves. The holes communicate with each other through channels passing inside the bone. Down depart mastoid and subulate processes. The drum part, the smallest of all, is located around external auditory holes. On the back of the pyramid is internal auditory opening.
Rice. 29. Skull, front view:
1 - supraorbital notch / hole; 2 - parietal bone; 3 - sphenoid bone, large wing; 4 - temporal bone; 5 - eye socket; 6 - orbital surface of the large wing of the sphenoid bone; 7 - zygomatic bone; 8 - infraorbital foramen; 9 - pear-shaped aperture; 10 - upper jaw; 11 - teeth; 12 - chin hole; 13 - lower jaw; 14 - anterior nasal spine; 15 - coulter; 16 - lower nasal concha; 17 - middle nasal concha; 18 - infraorbital margin; 19 - ethmoid bone, perpendicular plate; 20 - sphenoid bone, small wing; 21 - nasal bone; 22 - supraorbital margin: 23 - frontal notch/foramen; 24 - frontal bone
Rice. thirty.Skull, right side view:
1 - frontal bone; 2 - wedge-frontal suture; 3 - wedge-scaly seam; 4 - sphenoid bone, large wing; 5 - supraorbital notch/hole; 6 - ethmoid bone; 7 - lacrimal bone; 8 - nasal bone; 9 - infraorbital foramen; 10 - upper jaw; 11 - lower jaw; 12 - chin hole; 13 - zygomatic bone; 14 - zygomatic arch; 15 - temporal bone, styloid process; 16 - external auditory meatus; 17 - temporal bone, mastoid process; 18 - temporal bone, scaly part; 19 - lambdoid seam; 20 - occipital bone; 21 - parietal bone; 22 - scaly seam; 23 - wedge-parietal suture; 24 - coronal suture
Rice. 31. Skull, rear view:
1 - external occipital protrusion; 2 - parietal bone; 3 - lambdoid seam; 4 - temporal bone, scaly part; 5 - temporal bone, pyramid, stony part; 6 - mastoid opening; 7 - temporal bone, mastoid process; 8 - temporal bone, styloid process; 9 - sphenoid bone, pterygoid process; 10 - incisive holes; 11 - teeth; 12 - lower jaw; 13 - upper jaw, palatine process; 14 - hole mandible; 15 - palatine bone; 16 - occipital condyle; 17 - coulter; 18 - lower vynynaya line; 19 - upper vynynaya line; 20 - the highest protruding line; 21 - occipital area; 22 - sagittal suture
hearing bones, located inside the temporal bone, are discussed in the section "Teaching about the sense organs - esthesiology."
Sphenoid bone(os sphenoidale) unpaired, located in the middle of the base of the skull. She has 4 parts: body and 3 pairs of shoots of which 2 pairs are directed laterally and are named small and big wings. Third pair of branches (pterygoid) turned downward. The body has a cavity (sphenoid sinus) and deepening (turkish saddle), which houses the pituitary gland. On the processes there are holes, grooves and channels for the passage of blood vessels and nerves.
Bones of the facial skull
upper jaw(maxilla) steam room, located in the center of the face and connected to all its bones. It distinguishes body and 4 process, of which frontal pointing up alveolar- way down, palatine- medially, and zygomatic - laterally. The body has a large cavity - maxillary sinus. There are 4 surfaces on the body: anterior, infratemporal, orbital and nasal. The frontal and zygomatic processes articulate with the bones of the same name, the palatine - with a similar process of the other upper jaw, and the alveolar contains dental alveoli, in which the teeth are placed.
Lower jaw(mandibula) unpaired. It is the only movable bone in the skull. It has body and 2 branches. In the body, the base of the lower jaw and located above it are distinguished alveolar part, containing dental alveoli. On the base outside there is chin protrusion. The branch includes 2 processes: condylar, ending head of the lower jaw to form the temporomandibular joint, and coronary, which is the site of muscle attachment.
Cheekbone(os zygomaticum) steam room, has frontal and temporal processes, connecting with the bones of the same name.
palatine bone(os palatine) steam room, located behind the upper jaw. Consists of 2 plates: horizontal, connecting with the palatine process of the upper jaw, and perpendicular, adjacent to the nasal surface of the body of the upper jaw.
lacrimal bone(os lacrimal) steam room, located in front of the medial wall of the orbit; nasal bone(os nasale) steam room, is the anterior bone that forms the nasal cavity; coulter(vomer)
unpaired bone that forms the back of the nasal septum; inferior turbinate(concha nasalis inferior) steam room, adjacent to the nasal surface of the body of the upper jaw.
An important part of the human musculoskeletal system is the skeleton, which consists of more than two hundred different bones. It enables people to move, supports internal organs. In addition, they are a concentration of minerals, as well as a shell that contains bone marrow.
Skeleton Functions
The various types of bones that make up the human skeleton primarily act as a means of supporting and supporting the body. Some of them serve as a receptacle for certain internal organs, for example, the brain, located in the bones of the skull, lungs and heart, located in the chest, and others.
We also owe the ability to make various movements and move around to our own skeleton. In addition, human bones contain up to 99% of the calcium found in the body. Red bone marrow is of great importance in human life. It is located in the skull, spine, sternum, collarbone and some other bones. Bone marrow produces blood cells: erythrocytes, platelets and leukocytes.
The structure of the bone
The anatomy of a bone has extraordinary properties that determine its strength. The skeleton must withstand a load of 60-70 kg - this is average weight person. In addition, the bones of the trunk and limbs work as levers that allow us to move and perform various activities. This is achieved due to their amazing composition.
Bones consist of organic (up to 35%) and inorganic (up to 65%) substances. The former include protein, mainly collagen, which determines the firmness and elasticity of tissues. Inorganic substances - calcium and phosphorus salts - are responsible for hardness. The combination of these elements gives the bones a special strength, comparable, for example, with cast iron. They can be perfectly preserved for many years, as evidenced by the results of various excavations. can disappear as a result of calcination of tissues, as well as when they are exposed to sulfuric acid. Minerals are very resistant to external influences.
Human bones are pierced by special tubules through which blood vessels. In their structure, it is customary to distinguish between compact and spongy substances. Their ratio is determined by the location of the bone in the human body, as well as the functions it performs. In those areas where resistance to heavy loads is required, a dense compact substance is the main one. Such a bone consists of many cylindrical plates placed one inside the other. spongy substance appearance resembles a honeycomb. In its cavities is red bone marrow, and in adults it is also yellow, in which fat cells are concentrated. The bone is covered by a special connective tissue sheath - the periosteum. It is permeated with nerves and blood vessels.
Bone classification
There are various classifications that cover all types of bones of the human skeleton, depending on their location, structure and functions.
1. By location:
- cranial bones;
- body bones;
- limb bones.
2. The following types of bones are distinguished by development:
- primary (appear from connective tissue);
- secondary (formed from cartilage);
- mixed.
3. The following types of human bones are distinguished by structure:
- tubular;
- spongy;
- flat;
- mixed.
Thus, different types of bones are known to science. The table makes it possible to more clearly present this classification.
tubular bones
Tubular long bones composed of both dense and spongy matter. They can be divided into several parts. The middle of the bone is formed by a compact substance and has an elongated tubular shape. This area is called the diaphysis. Its cavities first contain red bone marrow, which is gradually replaced by yellow, containing fat cells.
At the ends of the tubular bone is the epiphysis - this is the area formed by the spongy substance. Red bone marrow is placed inside it. The area between the diaphysis and the epiphysis is called the metaphysis.
During the period of active growth of children and adolescents, it contains cartilage, due to which the bone grows. Over time, the anatomy of the bone changes, the metaphysis completely turns into bone tissue. The long ones include the thigh, shoulder, bones of the forearm. Tubular small bones have a slightly different structure. They have only one true epiphysis and, accordingly, one metaphysis. These bones include the phalanges of the fingers, the bones of the metatarsus. They function as short levers of movement.
Spongy types of bones. Pictures
The name of the bones often indicates their structure. For example, spongy bones are formed from a spongy substance covered with a thin layer of compact. They do not have developed cavities, so the red bone marrow is placed in small cells. Spongy bones are also long and short. The former include, for example, the sternum and ribs. Short spongy bones are involved in the work of muscles and are a kind of auxiliary mechanism. These include vertebrae.
flat bones
These types of human bones, depending on their location, have different structure and perform certain functions. The bones of the skull are primarily protection for the brain. They are formed by two thin plates of dense substance, between which is located spongy. It has openings for veins. The flat bones of the skull develop from connective tissue. The scapula and also belong to the type of flat bones. They are formed almost entirely from a spongy substance that develops from cartilage tissue. These types of bones perform the function of not only protection, but also support.
mixed dice
Mixed bones are a combination of flat and short spongy or tubular bones. They develop in various ways and perform the functions that are necessary in a particular part of the human skeleton. Such types of bones as mixed are found in the body of the temporal bone, vertebrae. These include, for example, the clavicle.
cartilage tissue
Has an elastic structure. She shapes auricles, nose, some parts of the ribs. Cartilaginous tissue is also located between the vertebrae, as it perfectly resists the deforming force of loads. It has high strength, excellent resistance to abrasion and crushing.
Connection of bones
There are different ones that determine the degree of their mobility. The bones of the skull, for example, have a thin layer of connective tissue. However, they are absolutely immobile. Such a connection is called fibrous. Between the vertebrae are also areas of connective or cartilaginous tissue. Such a connection is called semi-movable, since the bones, although limited, can move a little.
Joints that form synovial joints have the highest mobility. The bones in the joint bag are held by ligaments. These fabrics are both flexible and durable. In order to reduce friction, a special oily fluid is located in the joint - synovia. It envelops the ends of the bones, covered with cartilage, and facilitates their movement.
There are several types of joints. As the name of the bones is determined by their structure, so the name of the joints depends on the shape of the bones that they connect. Each type allows you to perform certain movements:
- Ball joint. With this connection, the bones move in many directions at once. These joints include the shoulder and hip joints.
- Block joint (elbow, knee). Assumes movement exclusively in one plane.
- Cylindrical joint allows the bones to move relative to each other.
- Flat joint. It is inactive, provides movements of a small scope between two bones.
- Ellipsoidal joint. Thus, for example, the radius is connected to the bones of the wrist. They can move from side to side within the same plane.
- Thanks to saddle joint the thumb can move in different planes.
The impact of physical activity
The degree of physical activity has a significant impact on the shape and structure of bones. In different people, the same bone can have its own characteristics. With constant impressive physical exertion, the compact substance thickens, and the cavity, on the contrary, shrinks in size.
A long stay in bed, a sedentary lifestyle negatively affects the condition of the bones. Fabrics become thinner, lose their strength and elasticity, become brittle.
Changes under the influence of physical activity and the shape of the bones. Those places where muscles act on them can become flatter. With particularly intense pressure, small depressions may even occur over time. In areas of strong stretching, where ligaments act on the bones, thickenings, various irregularities, and tubercles can form. Especially such changes are typical for people professionally involved in sports.
A variety of injuries, especially those received in adulthood, also affect the shape of the bones. When the fracture grows together, all kinds of deformations can occur, which often adversely affect the effective management of one's body.
Age-related changes in bones
In different periods of a person's life, the structure of his bones is not the same. In infants, almost all bones consist of a spongy substance, which is covered with a thin layer of compact. Their continuous, up to a certain time, growth is achieved due to an increase in the size of cartilage, which is gradually replaced by bone tissue. This transformation continues until the age of 20 in women and up to about 25 in men.
How younger man, the more organic matter is contained in the tissues of its bones. Therefore, in early age they are elastic and flexible. In an adult, the volume of mineral compounds in bone tissue is up to 70%. At the same time, with a certain moment a decrease in the amount of calcium and phosphorus salts begins. Bones become brittle, so older people often experience fractures even as a result of a minor injury or a careless sudden movement.
These fractures take a long time to heal. There is a special disease characteristic of the elderly, especially women - osteoporosis. For its prevention, upon reaching the age of 50, it is necessary to consult a doctor for some research to assess the condition of the bone tissue. With appropriate treatment, the risk of fractures is significantly reduced and the healing time is shortened.
Bone as an organ (bone structure).
Bone, os, ossis, as an organ of a living organism, consists of several tissues, the most important of which is bone.
The chemical composition of bone and its physical properties.
The bone substance consists of two kinds of chemicals: organic (Uz), mainly ossein, and inorganic (2/z), mainly calcium salts, especially lime phosphate (more than half - 51.04%). If the bone is subjected to the action of a solution of acids (hydrochloric, nitric, etc.), then the lime salts dissolve (decalcinatio), and the organic matter remains and retains the shape of the bone, being, however, soft and elastic. If the bone is fired, then the organic matter burns out, and the inorganic remains, also retaining the shape of the bone and its hardness, but at the same time being very fragile. Consequently, the elasticity of the bone depends on ossein, and its hardness depends on mineral salts. The combination of inorganic and organic substances in a living bone gives it extraordinary strength and elasticity. This is confirmed and age-related changes bones. In young children, who have relatively more ossein, the bones are very flexible and therefore rarely break. On the contrary, in old age, when the ratio of organic and inorganic substances changes in favor of the latter, the bones become less elastic and more brittle, as a result of which bone fractures are most often observed in old people.
The structure of the bone.
The structural unit of the bone, visible through a magnifying glass or at low magnification of a microscope, is osteon , i.e., a system of bone plates concentrically located around a central canal containing vessels and nerves.
Osteons do not adjoin closely to each other, and the gaps between them are filled with interstitial bone plates. Osteons are located not randomly, but according to the functional load on the bone: in tubular bones parallel to the length of the bone, in spongy bones - perpendicular to the vertical axis, in flat bones of the skull - parallel to the surface of the bone and radially.
Together with the interstitial plates, the osteons form the main middle layer of the bone substance, covered from the inside (from the side of the endosteum) by the inner layer of the bone plates, and from the outside (from the side of the periosteum) by the outer layer of the surrounding plates. The latter is permeated with blood vessels that go from the periosteum to the bone substance in special perforating channels. The beginning of these channels is visible on the macerated bone in the form of numerous nutrient holes (foramina nut-rfcia). The blood vessels passing through the canals ensure the metabolism of the bones. Osteons consist of larger bone elements that are already visible to the naked eye on a cut or on a radiograph, - crossbars of bone substance, or trabeculae. Of these trabeculae, a twofold kind of bone substance is formed: if the trabeculae lie tightly, then it turns out dense compact substance, substantia compacta. If the trabeculae lie loosely, forming between them bone cells like a sponge, then it turns out spongy, trabecular substance, substantia spongiosa, trabecularis (spongia, Greek - sponge).
The distribution of compact and spongy substance depends on the functional conditions of the bone. A compact substance is found in those bones and in those parts of them that primarily perform the function of support (rack) and movement (levers), for example, in the diaphysis of tubular bones.
In places where, with a large volume, it is required to maintain lightness and at the same time strength, a spongy substance is formed, for example, in the epiphyses of tubular bones (Fig. 7).
The crossbars of the spongy substance are located not randomly, but naturally, also according to the functional conditions in which the given bone or part of it is located. Since the bones experience a double action - pressure and traction of the muscles, insofar as the bone crossbars are located along the lines of compression and tension forces. According to the different direction of these forces, different bones or even parts of them have a different structure. In the integumentary bones of the cranial vault, which primarily perform the function of protection, the spongy substance has a special character that distinguishes it from other bones that carry all 3 functions of the skeleton. This spongy substance is called diploe, diploe (double), since it consists of irregularly shaped bone cells located between two bone plates - the outer, lamina externa, and the inner, lamina interna. The latter is also called vitreous, lamina vftrea, since it breaks more easily when the skull is damaged than the outer one.
Bone cells contain Bone marrow - organ of hematopoiesis and biological defense of the body. It is also involved in the nutrition, development and growth of bones. In the tubular bones, the bone marrow is also located in the canal of these bones, which is therefore called the medullary cavity, cavitas medullaris.
Thus, all internal spaces of the bone are filled with bone marrow, which is an integral part of the bone as an organ.
Bone marrow comes in two varieties: red and yellow.
red bone marrow, medulla ossium rubra (for details of the structure, see the course of histology), has the appearance of a tender red mass, consisting of reticular tissue, in the loops of which there are cellular elements that are directly related to hematopoiesis (stem cells) and bone formation (bone builders - osteoblasts and bone destroyers - osteoclasts). It is permeated with nerves and blood vessels that feed, in addition to the bone marrow, the inner layers of the bone. The blood vessels and blood cells give the bone marrow its red color.
yellow bone marrow, medulla ossium flava, owes its color to the fat cells of which it mainly consists.
In the period of development and growth of the body, when large hematopoietic and bone-forming functions are required, red bone marrow predominates (fetuses and newborns have only red brain). As the child grows, the red brain is gradually replaced by yellow, which in adults completely fills the medullary cavity of the tubular bones.
Outside, the bone, with the exception of the articular surfaces, is covered with periosteum, periosteum (periosteum).
Periosteum- this is a thin, strong connective tissue film of pale pink color, surrounding the bone from the outside and attached to it with the help of connective tissue bundles - perforating fibers that penetrate the bone through special tubules. It consists of two layers: outer fibrous (fibrous) and inner bone-forming (osteogenic, or cambial). It is rich in nerves and blood vessels, due to which it participates in the nutrition and growth of the bone in thickness. Nutrition is carried out by blood vessels that penetrate in large numbers from the periosteum into the outer compact bone substance through numerous nutrient holes (foramina nutricia), and bone growth is carried out by osteoblasts located in the inner layer adjacent to the bone (cambial). The articular surfaces of the bone, free from the periosteum, are covered by articular cartilage, cartilage articularis.
Thus, the concept of bone as an organ includes bone tissue, which forms the main mass of bone, as well as bone marrow, periosteum, articular cartilage, and numerous nerves and vessels.
Control questions for the lecture:
1. The concept of the bone (solid) and connective tissue skeleton,
2. General overview of the human skeleton, classification of bones.
3. The structure of the bone as an organ, periosteum, bone marrow.
4. The structure of the osteon: haversian canals, bone plates; bone cells - osteoblasts, osteocytes, osteoclasts.
5. The structure of the bone; diaphysis, metaphysis, epiphysis, apophysis, compact and spongy substance.
6. Chemical composition of the bone.
Lecture #5
Bone in x-ray image. The influence of labor and sport on the structure of the bones of a living person. The relationship of social and biological factors in the structure of bones.
The purpose of the lecture. Consider the structure of the bone in the whole organism.
lecture plan:
1. Consider the X-ray anatomy of the bones.
2. Consider the dependence of bone development on internal and external factors.
3. To reveal the structural and functional relationships between the active and passive parts of the musculoskeletal system.
4. To reveal the role of the Russian scientist P.F. Lesgaft in the study of the interdependence of the muscular and skeletal systems.
5. Consider the relationship of social and biological factors in the formation of the human skeleton.
X-RAY ANATOMY OF BONES.
On radiographs, a compact and spongy substance is clearly distinguishable. The first gives an intense contrast shadow, corresponding to the plane of the cortical layer, and in the region of substantia spongiosa the shadow has a reticulate character (see Fig. 1).
Compact substance of the epiphyses of tubular bones and the compact substance of the bones, built mainly of spongy substance (carpal bones, tarsals, vertebrae), has the appearance of a thin layer bordering the spongy substance. This thin cortical layer appears to be thicker on the articular cavities than on the articular heads.
In the diaphysis of tubular bones compact the substance is different in thickness: in the middle part it is thicker, towards the ends it narrows. At the same time, between the two shadows of the cortical layer, the medullary cavity is visible in the form of some enlightenment against the background of the general shadow of the bone. If the named cavity is not traced throughout, this indicates the presence of a pathological process.
X-ray contours of the compact substance of the diaphysis clear and smooth. In places of attachment of ligaments and muscles, the contours of the bone are uneven. Against the background of the cortical layer of the diaphysis, thin bands of enlightenment are seen corresponding to the vascular channels. They are usually located obliquely: in the long tubular bones of the upper limb - closer and towards the elbow joint; in the long tubular bones of the lower limb - further and in the direction from knee joint; in the short tubular bones of the hand and foot - closer and towards the end, which does not have a true epiphysis.
Spongy substance on x-ray has the form of a looped network, consisting of bone crossbars with enlightenments between them. The nature of this network depends on the location of the bone plates in a given area, according to the lines of compression and tension.
Bone Development. X-ray examination of the skeletal system becomes possible from the 2nd month of uterine life, when ossification points appear on the basis of cartilage or connective tissue.
Appearance ossification points it is easily determined on radiographs, and these points, separated by cartilaginous tissue, look like separate bone fragments. They can give rise to erroneous diagnoses of fracture, fracture or necrosis (necrosis) of the bone. Because of this, knowledge of the location of the bone nuclei, the timing and order of their appearance in practical terms is extremely important.
Therefore, we describe ossification in all relevant places on the basis of data not from the anatomical study of corpses, but from X-ray anatomy (the study of a living person).
In cases of non-fusion of additional nuclei with the main part of the bone, they can be preserved for life in the form of independent, non-permanent or additional bones. Finding them on a radiograph can be a reason for diagnostic errors.
All major ossification nuclei appear in the bones of the skeleton before the onset of puberty, called puberty. FROM offensive puberty the fusion of the epiphyses with the metaphyses begins, i.e., the transformation of synchondrosis, connecting the bone epiphysis with the bone metaphysis, into synostosis. This is radiologically expressed in the gradual disappearance of enlightenment at the site of the metaepiphyseal zone, corresponding to the metaepiphyseal cartilage that separates the epiphysis from the metaphysis. Upon the onset of complete synostosis, traces of the former synchondrosis cannot be determined (Fig. 1).
Aging of the skeletal system. In old age, the skeletal system undergoes significant changes. On the one hand, there is a decrease in the number of bone plates and rarefaction of the bone (osteoporosis); on the other hand, it happens over-education bones in the form of bony growths (o s t e f i t o v) and calcification of the articular cartilage, ligaments and tendons at the site of their attachment to the bone.
Accordingly, the x-ray picture of the aging of the osteoarticular apparatus is composed of following changes, which should not be interpreted as symptoms of pathology (degeneration).
I. Changes caused by bone atrophy:
1) osteoporosis (on the radiograph, the bone becomes more transparent);
2) deformity of the articular heads (disappearance of their rounded shape, "grinding" of the edges, the appearance of "corners").
II. Changes caused by excessive deposition of lime in the connective tissue and cartilage formations adjacent to the bone:
1) narrowing of the joint "X-ray" gap due to calcification of the articular cartilage;
2) enhancement of the relief of the diaphysis due to calcification at the site of attachment of the tendons and their fibrous sheaths;
3) bone growths- osteophytes , formed as a result of calcification of ligaments at the site of their attachment to the bone.
The described changes are especially well traced in a backbone and a brush. In the rest of the skeleton, three main radiological symptoms of aging are observed: osteoporosis, increased bone relief, and narrowing of the joint spaces. In some people, these signs of aging are noticed early (30-40 years), in others - late (60-70 years) or do not occur at all.
Summing up the presentation of general data on the ontogenesis of the skeletal system, we can say that X-ray examination allows more accurate and deeper study of the development of the skeleton in its functioning state than the study of only cadaveric material.
At the same time, a number of normal morphological changes are noted:
1) the appearance of ossification points - basic and additional;
2) the process of their synostosis with each other;
3) senile involution of the bone.
The described changes are normal manifestations of age-related variability of the skeletal system. Consequently, the concept of "norm" cannot be limited only to an adult and considered as a single type. This concept must be extended to all other ages.
DEPENDENCE OF BONE DEVELOPMENT ON INTERNAL AND EXTERNAL FACTORS
The skeleton, like any organ system, is a part of the body, which reflects the various processes taking place in it. Therefore, many factors influence the development of the skeletal system.
Influence of internal factors. X-ray examination reveals a number of morphological changes in bones, depending on the activity of other organs. It is especially clear when radiography is determined connection between the skeletal system and endocrine glands. The active inclusion of the gonads entails the onset of puberty, puberty . Before this, in the prepubertal period, the activity of other endocrine glands, an appendage of the brain - the pituitary gland, is enhanced, with the function of which the appearance of ossification nuclei is associated. By the beginning of the prepubertal period, all the main ossification points appear, and there is a gender difference in the timing of their appearance: in girls, 1-4 years earlier than in boys. The onset of the prepubertal period associated with the function of the pituitary gland coincides with the appearance of the ossification nucleus in the pisiform bone, which belongs to the category of sesamoid bones.
On the eve of puberty, other sesamoid bones also ossify, namely, at the metacarpophalangeal joint of the first finger. The beginning of the pubertal period, when, in the words of the well-known researcher of the endocrine apparatus Bidl, "the sex glands begin to play the main melody in the endocrine concert", is manifested in the skeletal system by the onset of synostoses between the epiphyses and metaphyses, and the very first such synostosis is observed in I metacarpal bone. Therefore, on the basis of comparing it with other data on sexual development (the appearance of terminal vegetation, the onset of menstruation, etc.), synostosis of the 1st metacarpal bone is considered an indicator of incipient puberty, that is, an indicator of the onset of puberty; in St. Petersburg residents, synostosis of the 1st metacarpal bone occurs at the age of 15-19 in boys and at 13-18 in girls.
Complete puberty , also receives a certain reflection in the skeleton: at this time, synostoses of the epiphyses with metaphyses in all tubular bones end, which is observed in women aged 17-21 years, and in men - at 19-23 years. Since with the end of the synostosis process, the growth of bones in length ends, it becomes clear why men who puberty ends later than, in women, in the mass they are taller than women.
Taking into account this connection between the skeletal system and the endocrine system and comparing the data on the age characteristics of the skeleton with data on puberty and the general development of the organism, we can speak of the so-called "bone age". Due to this, according to the x-ray picture of some parts of the skeleton, especially the hand, it is possible to determine the age of a given individual or to judge the correctness of his ossification process, which is of practical importance for diagnosis, forensic medicine, etc. Moreover, if the "passport" age indicates the number of lived years (i.e., on the quantitative side), then the "bone" age to a certain extent indicates their qualitative side.
At x-ray examination also comes to light dependence of bone structure on the state of the nervous system, which, regulating all processes in the body, performs, in particular, the trophic function of the bone. At enhanced trophic function of the nervous system more bone tissue is deposited in the bone, and it becomes more dense, compact (osteosclerosis). On the contrary, when trophic weakening bone loss is observed - osteoporosis. The nervous system also influences the bone through the musculature, the contraction of which it controls (which will be discussed below). Finally, various parts of the central and peripheral nervous system determine the shape of the surrounding and adjacent bones. So, all the vertebrae form the spinal canal around spinal cord. The bones of the skull form a bone box around the brain and take the form of the latter. In general, bone tissue develops around elements of the peripheral nervous system, resulting in bone channels, furrows and pits that serve to pass nerves and other nerve formations (nodes).
The development of the bone is also in a very close dependent on the circulatory system. The entire process of ossification from the moment the first bone nucleus appears to the end of synostosis takes place with the direct participation of blood vessels, which, penetrating into the cartilage, contribute to its destruction and replacement by bone tissue. In this case, bone plates (Haversian) are deposited in a certain order around the blood vessels, forming Haversian systems with a central channel for the corresponding vessel. Consequently, the bone at its origin is built around the vessels. This also explains the formation of vascular channels and furrows in the bones at the places where arteries and veins pass and adjoin to them.
Ossification and bone growth after birth also proceeds in close dependent on blood supply. It is possible to outline a number of stages of age-related variability of the bone associated with the corresponding changes in the bloodstream (Fig. 2).
1. neonatal stage characteristic of the fetus (the last months of intrauterine development) and the newborn; the vascular bed of the bone is divided into a number of vascular regions (epiphysis, diaphysis, metaphysis, apophysis) that do not communicate with each other (closedness, isolation) and within which the vessels do not connect to each other, do not anastomose (terminal nature of the vessels, "limb") .
2. Infantile stage characteristic of children before the onset of synostosis; the vascular regions are still separated, but within each of them the vessels anastomose with each other and their terminal character disappears ("closed" in the absence of a "limb").
3. juvenile stage , characteristic of young men, begins with the establishment of connections between the vessels of the epiphysis and metaphysis through the metaepiphyseal cartilage, due to which the isolation of the epiphyseal begins to disappear. metaphyseal and diaphyseal vessels.
4. mature stage characteristic of adults; synostoses occur, and all intraosseous vessels form a single system: they are not “closed” and not “final”.
5. senile stage characteristic of the elderly; the vessels become thinner and the entire vascular network is poorer.
On the shape and position of the bones affect the inside, for which they form bone receptacles, beds, pits, etc.
The formation of the skeleton and organs refers to the beginning of embryonic life; in their development, they influence each other, which is why the correspondence of the organs and their bone containers, for example, the chest and lungs, the pelvis and its organs, the skull and the brain, etc., is obtained.
In the light of these relationships, the development of the entire skeleton must be considered.
Influence of external (social) factors on the structure and development of the skeleton. The unity of form and function in the structure of bones. Influencing nature in the process labor activity, a person sets in motion his natural tools - arms, legs, fingers, etc. In the tools of labor, he acquires new artificial organs that complement and lengthen the natural organs of the body, changing their structure. And man himself "... at the same time changes his own
 |
nature." Consequently, work processes have a significant impact on the human body as a whole, on its apparatus of movement, including the skeletal system.
Especially pronounced on the skeleton muscle work. As experimental studies by P.F. Lesgaft showed, the stronger the work of the muscles, the better the bone develops, and vice versa. At the places of attachment of the tendons, protrusions are formed (tubercles, processes,
roughness), and in places
Rice. 3. Radiographs of the metatarsal bones.
places of attachment of the muscles of the ballerina (a) and sedentary workers (b).
attachments of muscle bundles - smooth or concave surfaces (fossae).
RELATIONSHIPS OF THE ACTIVE AND PASSIVE PARTS OF THE LOCOMOTOR APPARATUS
The more developed the musculature, the better the places of muscle attachment are expressed on the bones. That is why the relief of the bone, due to the attachment of muscles, is more pronounced in an adult than in a child, in men it is stronger than in women.
Prolonged and systematic muscle contractions, as occurs during physical exercise and professional work, gradually cause a change in bone metabolism through the reflex mechanisms of the nervous system, resulting in an increase in bone substance, called working hypertrophy (Fig. 3). This working hypertrophy causes changes in the size, shape and structure of the bones, which are easily determined radiographically in living people.
Different professions require different physical work, which is the reason for the different degree of participation of certain bones in this work.
Increased physical load on the movement apparatus causes working hypertrophy of the bones, as a result of which their shape, width and length change, as well as the thickness of the compact substance and the size of the bone marrow space; the structure of the spongy substance also changes.
Bone width. So, for loaders, the width of the bones, as their professional experience increases, reaches significantly large sizes than those of office workers.
P.F. Lesgaft revealed a number of regularities in the relationship between the active and passive parts of the musculoskeletal system. They established:
1. Bones develop the stronger, the greater the activity of the muscles surrounding them; with less load on the organs, they become thinner, longer, narrower and weaker.
2. The shape of the bones changes depending on the pressure of the surrounding organs (muscles, skin, eyes, teeth, etc.), they thicken and move in the direction of least resistance.
3. The shape of the bone also changes from the pressure of the outer parts, the bone grows more slowly from the side of increased external pressure, bending under the influence of a unilateral action.
4. Fascia - thin membranes that cover and separate the muscles and are under their direct influence, also exert lateral pressure on the bones.
5. Bones are active in relation to the form of their structure (architecture), they play the role of racks or supports for the surrounding organs.
RELATIONSHIP OF SOCIAL AND BIOLOGICAL IN THE STRUCTURE OF BONES
The bone is not a frozen model that does not change after its formation, as previously thought. Such a metaphysical view has been overcome by modern anatomy, which considers the vital activity of a bone even in an adult as an ongoing metabolism with other tissues of the body, as a dialectical unity and struggle between two opposite processes - bone formation and bone destruction (resorption; resorptio - resorption). As a result of this struggle, constant change bone structures and its chemical composition; so that, for example, the femur is completely renewed within 50 days. At the same time, the bone obeys a number of biological laws: adaptation (adaptation) to new living conditions, the unity of the organism and the environment, the unity of form and function, variability as a result of exercise or non-exercise, the effect of mechanical compression of one part on another, etc. The morphological expression of these laws in relation to the skeleton is the restructuring of the bone structure (bone restructuring) in accordance with the changing functional needs, as already mentioned above.
Such, in brief, is the "biological side" of the relationship between the social and the biological. With regard to the "social side", here it is necessary to keep in mind the following.
Various social factors (profession, lifestyle, diet, etc.) are associated with different physical activity, which determines the different degree of participation of certain bones in this work. The work of a professional worker causes a long stay of the body in one position or another (for example, a bent position above the machine or desk) or a constant change in body position in one direction or another (for example, bending the torso forward and throwing it back in carpenters). Therefore, the nature of the professional load and its volume determine the greater or lesser participation in the work of this section of the skeleton and each bone separately and determine the different nature and degree of restructuring of its structure. When changing profession, bone restructuring is observed in the direction of strengthening or weakening of working hypertrophy, depending on the nature of the professional load. Bone growth in length is enhanced with favorable physical activity.
Bone aging occurs later in workers who have properly organized long-term physical labor, which does not cause premature wear and tear of bone tissue.
The stated facts of individual variability of the skeletal system are due to both biological and social factors. Environmental stimuli are perceived by the body biologically and lead to the restructuring of the skeleton. The ability of bone tissue to adapt to changing functional needs through bone remodeling is biological cause variability of bones, and the nature of the profession, the volume of professional workload, the intensity of labor, the lifestyle of a given person and other social factors are the social causes of this variability.
Such is the relationship between the social and the biological in the structure of the skeleton. Knowing this relationship, it is possible to directly influence the structure of the skeletal system by selecting the appropriate exercise in work and sports and through changes in social conditions of life.
Control questions for the lecture:
1. X-ray anatomy of bones.
2. Dependence of bone development on internal and external factors.
3. Structural and functional relationship between the active and passive parts of the musculoskeletal system.
4. The role of the Russian scientist P.F. Lesgaft in the study of the interdependence of the muscular and skeletal systems.
5. The relationship of social and biological factors in the formation of the human skeleton.
Lecture #6
General artrosyndesmology.
The purpose of the lecture. Consider functional, anatomical features various kinds bone connections.
lecture plan:
1. Consider the development of bone joints in phylogeny.
2. Consider the classification of bone connections.
3. Reveal functional anatomy syndesmoses.
4. To reveal the functional anatomy of synchrodroses, synostoses, semi-joints.
5. Consider the classification of joints according to the number of articular surfaces and the shape of the articular surfaces.
6. Consider the classification of joints according to the number of axes of movement.
7. Consider the general characteristics of combined joints and complex joints.
8. Consider the structure of the main and auxiliary elements of the joints.
9. To reveal the main patterns of the biomechanics of the joints.
10. Reveal the functional and morphological features of the spinal column as a whole.
11. Expand the functional and morphological features of the pelvis as a whole.
12. Reveal the functional and morphological features of the foot as a whole.
DEVELOPMENT OF BONE JOINTS IN PHYLOGENESIS
The initial form of connection of bones is their fusion with the help of connective or (later) cartilaginous tissue. However, this continuous way of connecting the bones limits the range of motion. With the formation of bone levers of movement in the tissue between the bones, as a result of resorption of the latter, cracks and cavities appear, resulting in the new kind connection of bones - discontinuous, articulation. The bones began not only to connect, but also to articulate, joints were formed that allowed the bone levers to produce extensive movements. Thus, in the process of phylogenesis, 2 types of bone connections developed: the initial one was continuous, continuous with a limited range of motion, and the later one was discontinuous, which allowed for extensive movements. Reflecting this phylogenetic process in human embryogenesis, the development of bone joints goes through these 2 stages. Initially, the rudiments of the skeleton are continuously interconnected by layers of mesenchyme. The latter turns into a connective tissue, from which an apparatus is formed that binds the bones. If the areas of connective tissue located between the bones turn out to be continuous, then a continuous continuous connection of the bones will turn out - fusion, go synarthrosis. If a cavity is formed inside them by resorption of the connective tissue, then another type of connection arises - cavitary, or discontinuous, - diarthrosis.
Thus, according to the development, structure and function, all bone joints can be divided into 2 large groups:
1. Continuous connections - synarthroses(BNA) - earlier in development, immobile or inactive in function.
2. Discontinuous connections - diarthrosis(BNA) - later in development and more mobile in function.
Between these forms there is a transition - from continuous to discontinuous or vice versa. It is characterized by the presence of a small gap that does not have the structure of a real articular cavity, as a result of which this form is called semi-joint - symphysis, symphysis (BNA).
Each human bone is a complex organ: it occupies a certain position in the body, has its own shape and structure, and performs its own function. All types of tissues take part in bone formation, but bone tissue predominates.
General characteristics of human bones
Cartilage covers only the articular surfaces of the bone, the outside of the bone is covered with periosteum, and the bone marrow is located inside. Bone contains adipose tissue, blood and lymphatic vessels, and nerves.
Bone has high mechanical properties, its strength can be compared with the strength of metal. The chemical composition of a living human bone contains: 50% water, 12.5% organic substances of a protein nature (ossein), 21.8% inorganic substances (mainly calcium phosphate) and 15.7% fat.
Types of bones by shape divided into:
- Tubular (long - shoulder, femoral, etc.; short - phalanges of the fingers);
- flat (frontal, parietal, scapula, etc.);
- spongy (ribs, vertebrae);
- mixed (wedge-shaped, zygomatic, lower jaw).
The structure of human bones
The basic structural unit of bone tissue is osteon, which is visible under a microscope at low magnification. Each osteon includes from 5 to 20 concentrically arranged bone plates. They resemble cylinders inserted into each other. Each plate consists of intercellular substance and cells (osteoblasts, osteocytes, osteoclasts). In the center of the osteon there is a channel - the channel of the osteon; blood vessels run through it. Intercalated bone plates are located between adjacent osteons.
Bone is formed by osteoblasts, releasing the intercellular substance and walling up in it, they turn into osteocytes - cells of a process form, incapable of mitosis, with weakly expressed organelles. Accordingly, the formed bone contains mainly osteocytes, and osteoblasts are found only in areas of growth and regeneration of bone tissue.
The largest number of osteoblasts is located in the periosteum - a thin but dense connective tissue plate containing many blood vessels, nerve and lymph endings. The periosteum provides bone growth in thickness and nutrition of the bone.
osteoclasts contain a large number of lysosomes and are able to secrete enzymes, which can explain the dissolution of bone substance by them. These cells take part in the destruction of the bone. At pathological conditions in the bone tissue, their number sharply increases.
Osteoclasts are also important in the process of bone development: in the process of building the final shape of the bone, they destroy calcified cartilage and even newly formed bone, “correcting” its primary shape.
Bone structure: compact and spongy substance
On the cut, sections of the bone, two of its structures are distinguished - compact matter(bone plates are located densely and in an orderly manner), located superficially, and spongy substance(bone elements are located loosely), lying inside the bone.
Such a structure of bones fully corresponds to the basic principle of structural mechanics - to ensure maximum strength of the structure with the least amount of material and great ease. This is also confirmed by the fact that the location of the tubular systems and the main bone beams corresponds to the direction of action of the forces of compression, tension and twisting.
The structure of bones is a dynamic reactive system that changes throughout a person's life. It is known that in people engaged in heavy physical labor, the compact layer of bone reaches a relatively large development. Depending on the change in the load on individual parts of the body, the location of the bone beams and the structure of the bone as a whole may change.
Connection of human bones
All bone joints can be divided into two groups:
- Continuous connections, earlier in development in phylogenesis, immobile or inactive in function;
- intermittent connections, later in development and more mobile in function.
Between these forms there is a transition - from continuous to discontinuous or vice versa - semi-joint.
The continuous connection of the bones is carried out through connective tissue, cartilage and bone tissue (the bones of the skull itself). A discontinuous connection of bones, or a joint, is a younger formation of a connection between bones. All joints have a common structural plan, including the articular cavity, articular bag and articular surfaces.
Articular cavity it is allocated conditionally, since normally there is no void between the articular bag and the articular ends of the bones, but there is liquid.
Articular bag covers the articular surfaces of the bones, forming a hermetic capsule. The articular bag consists of two layers, the outer layer of which passes into the periosteum. The inner layer secretes a fluid into the joint cavity, which plays the role of a lubricant, ensuring the free sliding of the articular surfaces.
Types of joints
The articular surfaces of the articulating bones are covered with articular cartilage. The smooth surface of the articular cartilage promotes movement in the joints. The articular surfaces are very diverse in shape and size, they are usually compared with geometric figures. Hence and names of joints according to shape: spherical (shoulder), elliptical (radio-carpal), cylindrical (radio-ulnar), etc.
Since the movements of the articulating links are made around one, two or many axes, joints are also usually divided by the number of axes of rotation into multiaxial (spherical), biaxial (elliptical, saddle) and uniaxial (cylindrical, block-shaped).
Depending on the number of articulating bones joints are divided into simple, in which two bones are connected, and complex, in which more than two bones are articulated.
Human bones begin to form in the womb, but at first they are very soft. This is due to the fact that their bulk is made up of connective tissue. The growth of bones stops and the complete formation of the skeleton takes place - approximately at the age of 22 years.
In total, there are more than two hundred bones in the skeleton of an adult (surprisingly, the skeleton of a newborn consists of more than two hundred and seventy!), Which differ not only in form, but also in content. In addition, each of them performs its own strictly defined function.
So, the bones are divided into three groups: short, wide or flat, long, which are also called tubular. Let's talk about each group separately.
Wide bones do not have cavities inside. They are the strongest. Such bones in some cases create protection for the internal organs and have a curved shape, for example, the skull.
Bones that resemble a pipe in a section are called so - tubular, long. In their internal cavity is the bone marrow. Due to the fact that the bone inside is empty, it is quite light, but this does not negatively affect the strength. Tubular or long bones along the main length are cylindrical in shape, closer to the ends they expand somewhat, and at the very ends they are completely spherical. For example: tubular bones are the bones of the upper and lower extremities.
Short bones, on the contrary, do not have internal cavities, however, despite this, they are less durable than tubular ones. These bones in the human skeleton are represented, for example, by vertebrae. Some bones of the wrist, as well as the heel of the foot, also belong to the short group.
Despite different functions or forms, the presence of cavities or their absence, the bones have the same structure. All bones are made up of three layers, which resemble the annual rings of tree trunks. The top layer is dense bone tissue (periosteum, inside of which are nerves and blood vessels). The next layer is a dense substance. It provides strength to bones. The third layer of bone is made up of spongy bone. Outwardly, it is, indeed, very similar to an ordinary foam rubber sponge (thin channels penetrate its entire plane).
In tubular bones, the layer of dense bone substance is thicker than in short and wide ones, which for the most part have spongy tissue.
The skeleton carries the bulk of the human body, so it would not be superfluous to recall that calcium and phosphorus strengthen bones, and their lack in the body inevitably leads to their fragility and brittleness. Proper nutrition, eating foods with sufficient calcium and phosphorus, will help to avoid these problems. Do not forget that not the most favorable way for the condition of the bones can also be affected by excessive physical activity. Keep in mind that neglect of your health in youth can cause serious diseases of the musculoskeletal system in adulthood. In addition, over the years, the bones and so become weaker.
We advise you to read
Aphorisms and humor on restaurant topics Sayings about restaurants
Quotes about restaurants and eateries Quotes about cafes and people
Difference Between Ruffed Flounder and Common Flounder Fish Ruff Flounder
Ksenia Borodina first told why she reconciled with her cheating husband Borodina is divorcing Kurban
