In case of veterinary-sanitary or forensic examinations the doctor has to determine the type of animal by the carcass, corpse, their parts or individual bones. Often the decisive factor is the presence or absence of some detail or shape feature. Knowledge of comparative anatomical features The structure of the bones allows us to confidently draw a conclusion about the type of animal.

CERVICAL VERTEBRA - vertebrae cervicales.

Atlas - atlas - first cervical vertebra (Fig. 22).

In cattle, the transverse processes (atlas wings) are flat, massive, set horizontally, their caudolateral acute angle is pulled back, and the dorsal arch is wide. The wing has an intervertebral and alar foramen, but no transverse one.

The ovine caudal margin of the dorsal arch has a deeper, gentle notch, and there are also only two openings on the wing.

Rice. 22. Atlas cows (I), sheep Ш), goats (III), horses (IV), pigs (V), dogs (VI)

In goats, the lateral edges of the wings are slightly rounded, and the caudal notch of the dorsal arch is deeper and narrower than in sheep and cattle, and there is no transverse foramen.

In horses, on significantly developed, thinner, inclined wings, in addition to the alar and intervertebral foramina, there is a transverse foramen. The caudal edge of the dorsal arch has a deep, gently sloping notch.

In pigs, all cervical vertebrae are very short. Atlas has massive narrow wings with thickened rounded edges. The wing has all three openings, but the transverse one can be seen only along the caudal edge of the atlas wings, where it forms a small canal.

In dogs, the atlas has widely spaced lamellar wings with a deep triangular notch along its caudal margin. There are both intervertebral and transverse foramina, but instead of the alar foramen there is an alar notch - incisure alaris.

Axis, or epistropheus, - axis s. epistropheus - second cervical vertebra (Fig. 23).

Rice. 23. Axis (epistrophe) of a cow (1), sheep (II), goat (III), horse (IV), pig (V), dog (VI)

Rice. 24. Cervical vertebrae (middle) cow* (O, horses (II), pigs (III), dogs (IV)

In cattle, the axial vertebra (epistropheus) is massive. The odontoid process is lamellar, semi-cylindrical in shape. The crest of the axial vertebra is thickened along the dorsal edge, and the caudal articular processes at its base project independently.

In horses, the axial vertebra is long, the odontoid process is wide, flattened, the crest of the axial vertebra bifurcates in the caudal part, and on the ventral side of this bifurcation lie the articular surfaces of the caudal articular processes.

In pigs, the epistrophy is short, the odontoid process in the form of a wedge has a conical shape, and the ridge is high (increases in the caudal part).

In dogs, the axial vertebra is long, with a long wedge-shaped odontoid process; the crest is large, lamellar, protrudes forward and hangs over the odontoid process.

Typical cervical vertebrae - vertebrae cervicales - third, fourth and fifth (Fig. 24).

In cattle, the typical cervical vertebrae are shorter than in the horse, the fossa and head are well defined. In the bifurcated transverse process, its cranioventral part (costal process) is large, lamellar, extended downward, the caudodorsal branch is directed laterally. The spinous processes are round, well defined and directed cephalad.

Horses have long vertebrae with a well-defined head, fossa and ventral ridge. The transverse process is bifurcated along the sagittal plane, both parts of the process are approximately equal in size. There are no spinous processes (in their place there are scallops).

Pig vertebrae are short, the head and fossa are flat. The costal processes are wide below, oval-rounded, drawn down, and the caudodorsal plate is directed laterally. There are spinous processes. An additional cranial intervertebral foramen is very typical for the cervical vertebrae of pigs.

Dogs have typical cervical vertebrae that are longer than pigs, but the head and fossa are also flat. The plates of the transverse costal process are almost identical and bifurcate along the same sagittal plane (as in the horse). Instead of spinous processes there are low ridges.

Sixth and seventh cervical vertebrae.

In cattle, on the sixth cervical vertebra, the powerful plate of the costal process extended ventrally has a square shape; on the body of the seventh there is a pair of caudal costal facets; the transverse process is not bifurcated. The lamellar spinous process is high. There is no transverse hole, like the horse and pig.

In horses, the sixth vertebra has three small plates on the transverse process, the seventh is massive, does not have a transverse foramen, is shaped like the first thoracic vertebra of a horse, but has only one pair of caudal costal facets and a low spinous process on the body.

Rice. 25. Thoracic vertebrae of a cow (I), horse (II), pig (III), dog (IV)

The sixth vertebra of the pig has a wide, powerful oval-shaped plate of the transverse process extended ventrally; on the seventh there are double intervertebral foramina and the spinous process is high, lamellar, and set vertically.

In dogs, the sixth vertebra has a wide plate of the costal process beveled from front to back and downwards; on the seventh, the spinous process is set perpendicularly, has an awl-shaped shape, caudal costal facets may be absent.

Thoracic vertebrae - vertebrae thoracicae (Fig. 25).

Cattle have 13 vertebrae. In the area of ​​the withers, the spinous processes are wide, lamellar, and caudally inclined. Instead of a caudal vertebral notch, there may be an intervertebral foramen. The diaphragmatic vertebra is the 13th with a vertical spinous process.

Horses have 18-19 vertebrae. In the area of ​​the withers, the 3rd, 4th and 5th spinous processes have club-shaped thickenings. The articular processes (except the 1st) have the appearance of small contiguous articular surfaces. Diaphragmatic vertebra - 15th (sometimes 14th or 16th).

Pigs have 14-15 vertebrae, maybe 16. The spinous processes are wide, lamellar, vertically set. At the base of the transverse processes there are lateral openings running from top to bottom (dorsoventrally). There are no ventral ridges. Diaphragmatic vertebra - 11th.

Dogs have 13 vertebrae, rarely 12. The spinous processes in the withers area at the base are curved and directed caudally. The first spinous process is the highest; on the latter, accessory and mastoid processes. Diaphragmatic vertebra - 11th.

Lumbar vertebrae - vertebrae lumbales (Fig. 26).

Cattle have 6 vertebrae. They have a long body, slightly narrowed in the middle part. ventral ridge. The transverse costal (transverse) processes are dorsally (horizontally) located, long, lamellar, with pointed, uneven edges and ends curved cranially. The articular processes are powerful, widely spaced, with strongly concave or convex articular surfaces.

Horses have 6 vertebrae. Their bodies are shorter than those of cattle, the transverse costal processes are thickened, especially the last two or three, on which flat articular surfaces are located along the cranial and caudal edges (in old horses they often synostose). The caudal surface of the transverse costal process of the sixth vertebra is connected by a joint to the cranial edge of the wing of the sacral bone. Normally, there is never synostosis here. The articular processes are triangular in shape, less powerful, closer together, with flatter articular surfaces.

Rice. 26. Lumbar vertebrae of a cow (I), horse (I), pig (III), dog (IV)

Pigs have 7, sometimes 6-8 vertebrae. The bodies are long. The transverse costal processes are horizontally located, lamellar, slightly curved, have lateral notches at the base of the caudal edge and lateral openings closer to the sacrum. The articular processes, like those of ruminants, are powerful, widely spaced, strongly concave or convex, but, unlike ruminants, they have mastoid processes, making them more massive.

Dogs have 7 vertebrae. The transverse costal processes are lamellar and directed cranioventrally. The articular processes have flat articular, slightly inclined surfaces. The accessory and mastoid (on the cranial) processes are strongly pronounced on the articular processes.

The sacral bone is os sacrum (Fig. 27).

In cattle, 5 vertebrae are fused. They have massive quadrangular wings located almost on a horizontal plane, with a slightly raised cranial edge. The spinous processes have fused to form a powerful dorsal ridge with a thickened edge. The ventral (or pelvic) sacral foramina are extensive. Complete synostosis of the vertebral bodies and arches normally occurs by 3-3.5 years.

In horses, 5 fused vertebrae have horizontally located triangular-shaped wings with two articular surfaces - auricular, dorsal for connection with the wing of the iliac bone of the pelvis and cranial for connection with the transverse costal process of the sixth lumbar vertebra. The spinous processes grow together only at the base.

In pigs, 4 vertebrae are fused. The wings are rounded, placed along the sagittal plane, the articular (ear-shaped) surface is on their lateral side. There are no spinous processes. Interarch openings are visible between the arches. Normally, synostosis occurs by 1.5-2 years.

In dogs, 3 vertebrae are fused. The wings are rounded, set, like those of a pig, in the sagittal plane with a laterally located articular surface. In the 2nd and 3rd vertebrae the spinous processes are fused. Synostosis is normal by 6-8 months.

Tail vertebrae - vertebrae caudales s. coccygeae (Fig. 28),

Cattle have 18-20 vertebrae. Long, on the dorsal side of the first vertebrae rudiments of arches are visible, and on the ventral side (on the first 9-10) there are paired hemal processes, which on the 3rd-5th vertebrae can form hemal arches. "The transverse processes are wide, lamellar, curved ventrally.

Fig 27. Sacral bone of a cow (1), sheep (I), goat (III), horse (IV), pig (V), dog (VI)

Horses have 18-20 vertebrae. They are short, massive, retain arches without spinous processes; only on the first three vertebrae the transverse processes are flat and wide, disappearing on the last vertebrae.

Pigs have 20-23 vertebrae. They are long, arched with spinous processes, inclined caudally, preserved on the first five to six vertebrae, which are flatter, then become cylindrical. The transverse processes are wide.

Rice. 28. Caudal vertebrae of a cow (I), horse (II), pig (III), dog (IV)

Dogs have 20-23 vertebrae. On the first five to six vertebrae, the arches, cranial and caudal articular processes are preserved. The transverse processes are large, long, extended caudoventrally.

Ribs - costae (Fig. 29, 30).

Cattle have 13 pairs of ribs. They have a long neck. The first ribs are the strongest and the shortest and straightest. The middle ones are lamellar, widening significantly downwards. They have a thinner caudal edge. The hind ones are more convex, curved, with the head and tubercle of the ribs closer together. The last rib is short, thins downward, and may be hanging. It can be felt in the upper third of the costal arch.

Synostosis of the head and tubercle of the rib with the body in young animals does not occur simultaneously and goes from front to back. The first to fuse with the body is the head and tubercle of the first rib. The articular surface of the tubercle is saddle-shaped. The sternal ends of the ribs (2nd to 10th) have articular surfaces for connection with the costal cartilages, which have articular surfaces at both ends. There are 8 pairs of sternal ribs.

Horses have 18-19 pairs of ribs. Most of them are of uniform size along the entire length, the first is significantly expanded ventrally, up to the tenth the curvature and length of the ribs increase, then begin to decrease. The first 6-7 ribs are the widest and most lamellar. Unlike ruminants, their caudal edges are thicker and their neck is shorter. The tenth rib is almost tetrahedral. There are 8 pairs of sternal ribs.

Pigs often have 14, maybe 12 or up to 17 pairs of ribs. They are narrow, from the first to the third or fourth the width increases slightly. They have articular surfaces for connection with the costal cartilages. In adults, the sternal ends are narrowed, in piglets they are slightly widened. On the tubercles of the ribs there are small flat statutory facets; the bodies of the ribs have a faintly visible spiral turn. There are 7 (6 or 8) pairs of sternal ribs.

Dogs have 13 pairs of ribs. They are arched, especially in the middle part. Their length increases to the seventh rib, their width to the third or fourth, and their curvature to the eighth rib. On the tubercles the facet ribs are convex, there are 9 pairs of sternal ribs.

The breast bone is sternum (Fig. 31).

In cattle it is powerful and flat. The handle is rounded, raised, does not protrude beyond the first ribs, and is connected to the body by a joint. The body expands caudally. On the xiphoid process there is a significant plate of xiphoid cartilage. Along the edges there are 7 pairs of articular costal fossae.

In horses it is laterally compressed. It has a significant cartilaginous addition on the ventral edge, forming a ventral ridge, which protrudes on the handle, rounding, and is called a hawk. In adult animals, the manubrium and body are fused. Cartilage without xiphoid process. Along the dorsal edge of the sternum there are 8 pairs of articular costal fossae.

Rice. 29. Ribs of a cow (I), horse (II)

Rice. 30. Vertebral end of horse ribs

Rice. 31. Cow breastbone (I). sheep (II), goats (III), horses (IV), pigs (V), dogs (VI)

In pigs, like in cattle, it is flat, connected to the handle by a joint. The handle, unlike ruminants, in the form of a rounded wedge protrudes in front of the first pairs of ribs. The xiphoid cartilage is elongated. On the sides there are (7-8) pairs of articular costal fossae.

In dogs, it is in the form of a round, bead-shaped stick. The handle protrudes in front of the first ribs with a small tubercle. The xiphoid cartilage is rounded, on the sides there are 9 pairs of articular costal fossae.

Chest - thorax.

In cattle it is very voluminous, in the front part it is laterally compressed, and has a triangular exit. Behind the shoulder blades it expands strongly in the caudal direction.

In horses, it is cone-shaped, long, slightly compressed from the sides, especially in the area where the shoulder girdles are attached.

Pigs have a long, laterally compressed, height and width various breeds vary.

Dogs are cone-shaped with steep sides, the inlet is rounded, the intercostal spaces - spatia intercostalia - are large and wide.

Self-test questions

1. What is the importance of the movement apparatus in the life of the body?

2. What functions does the skeleton perform in the body in mammals and birds?

3. What stages of development in phylo- and ontogenesis do the internal and external skeletons of vertebrates go through?

4. What changes occur in the bones with increasing static load (with limited motor activity)?

5. How is bone built as an organ and what differences are there in its structure in young growing organisms?

6. What departments is it divided into? spinal column in terrestrial vertebrates and how many vertebrae are in each section in mammals?

7. In which department? axial skeleton Is there a complete bone segment?

8. What are the main parts of a vertebra and what parts are located on each part?

9. In which parts of the spinal column did the vertebrae undergo reduction?

10. By what signs will you distinguish the vertebrae of each part of the spinal column and by what signs will you determine species features vertebrae of each department?

11. What characteristic features structures have an atlas and an axial vertebra (epistropheus) in domestic animals? What is the difference between the atlas of pigs and the axial vertebra of ruminants?

12. By what feature can you distinguish the thoracic vertebra from the other vertebrae of the spinal column?

13. By what features can you distinguish the sacral bone of cattle, horses, pigs and dogs?

14. Name the main features of the structure of a typical cervical vertebra in ruminants, pigs/horses and dogs.

15. What is the most characteristic feature of the lumbar vertebrae? How do they differ between ruminants, pigs, horses and dogs?

Topic 1. Animal diversity

Practical work No. 5. Comparison of the structure of the skeletons of vertebrates

Target: examine the skeletons of vertebrate animals, find similarities and differences.

Work progress.

Conclusions. 1. All vertebrate animals have an internal skeleton, which has a general structure plan - the skeleton of the head (skull), the skeleton of the body (spine), the skeleton of the limbs, the skeleton of the girdles of the limbs. 2. The skeleton performs protective function, serves as a site of attachment for muscles that provide animal movement. 3. The structural features of the skeletons of vertebrate animals provide certain ways for these animals to move in space.

In the process of evolution, animals mastered more and more new territories, types of food, and adapted to changing living conditions. Evolution gradually changed the appearance of animals. In order to survive, it was necessary to search for food more actively, hide better or defend against enemies, and move faster. Changing along with the body, the musculoskeletal system had to ensure all these evolutionary changes. The most primitive protozoa have no supporting structures, move slowly, flowing with the help of pseudopods and constantly changing shape.

The first support structure to appear is cell membrane. She not only separated the body from external environment, but also made it possible to increase the speed of movement due to flagella and cilia. Multicellular animals have a wide variety of support structures and devices for movement. Appearance exoskeleton increased the speed of movement due to the development of specialized muscle groups. Internal skeleton grows with the animal and allows it to reach record speeds. All chordates have an internal skeleton. Despite significant differences in the structure of musculoskeletal structures in different animals, their skeletons perform similar functions: support, protection internal organs, body movement in space. The movements of vertebrates are carried out due to the muscles of the limbs, which carry out such types of movement as running, jumping, swimming, flying, climbing, etc.

Skeleton and muscles

The musculoskeletal system is represented by bones, muscles, tendons, ligaments and other connective tissue elements. The skeleton determines the shape of the body and, together with the muscles, protects the internal organs from all kinds of damage. Thanks to joints, bones can move relative to each other. The movement of bones occurs as a result of contraction of the muscles that are attached to them. In this case, the skeleton is a passive part of the motor apparatus that performs a mechanical function. The skeleton consists of dense tissues and protects internal organs and the brain, forming natural bone containers for them.

In addition to mechanical functions, the skeletal system performs a number of biological functions. Bones contain the main supply of minerals that are used by the body as needed. The bones contain red bone marrow, which produces blood cells.

The human skeleton includes a total of 206 bones - 85 paired and 36 unpaired.

Bone structure

Chemical composition of bones

All bones consist of organic and inorganic (mineral) substances and water, the mass of which reaches 20% of the mass of the bones. organic matter bones - ossein- has elastic properties and gives elasticity to bones. Minerals - salts of carbon dioxide and calcium phosphate - give bones hardness. High bone strength is ensured by a combination of ossein elasticity and hardness mineral matter bone tissue.

Macroscopic bone structure

On the outside, all bones are covered with a thin and dense film of connective tissue - periosteum. Only the heads of long bones do not have periosteum, but they are covered with cartilage. The periosteum contains many blood vessels and nerves. It provides nutrition to bone tissue and takes part in the growth of bone thickness. Thanks to the periosteum, broken bones heal.

Different bones have different structures. A long bone looks like a tube, the walls of which consist of a dense substance. This tubular structure long bones gives them strength and lightness. In cavities tubular bones located yellow bone marrow- rich in fat, loose connective tissue.

The ends of the long bones contain cancellous bone substance. It also consists of bone plates, forming many crossed partitions. In places where the bone is subject to the greatest mechanical load, the number of these partitions is highest. The spongy substance contains red bone marrow, the cells of which give rise to blood cells. Short and flat bones also have a spongy structure, only on the outside they are covered with a layer of damlike substance. The spongy structure gives bones strength and lightness.

Microscopic structure of bone

Bone tissue belongs to the connective tissue and has a lot of intercellular substance, consisting of ossein and mineral salts.

This substance forms bone plates located concentrically around microscopic tubules running along the bone and containing blood vessels and nerves. Bone cells, and therefore bone, are living tissue; she gets nutrients with blood, metabolism occurs in it and structural changes can occur.

Types of bones

The structure of bones is determined by a long process historical development, during which the body of our ancestors changed under the influence of the environment and adapted through natural selection to the conditions of existence.

Depending on the shape, there are tubular, spongy, flat and mixed bones.

Tubular bones are located in organs that make rapid and extensive movements. Among the tubular bones there are long bones(humeral, femoral) and short (phalanxes of fingers).

Tubular bones have a middle part - the body and two ends - the heads. Inside the long tubular bones there is a cavity filled with yellow bone marrow. The tubular structure determines the bone strength required by the body while requiring the least amount of material. During the period of bone growth, there is cartilage between the body and the head of the tubular bones, due to which the bone grows in length.

Flat Bones They limit cavities within which organs are placed (skull bones) or serve as surfaces for muscle attachment (scapula). Flat bones, like short tubular bones, are predominantly composed of spongy substance. The ends of long tubular bones, as well as short tubular and flat bones, do not have cavities.

Spongy bones constructed primarily of spongy substance covered thin layer compact. Among them, there are long spongy bones (sternum, ribs) and short ones (vertebrae, carpus, tarsus).

TO mixed bones These include bones that are made up of several parts that have different structures and functions (temporal bone).

Protrusions, ridges, and roughness on the bone are places where muscles are attached to the bones. The better they are expressed, the more developed the muscles attached to the bones are.

Human skeleton.

The human skeleton and most mammals have the same type of structure, consisting of the same sections and bones. But man differs from all animals in his ability to work and intelligence. This left a significant imprint on the structure of the skeleton. In particular, the volume of the human cranial cavity is much larger than that of any animal that has a body of the same size. The size of the facial part of the human skull is smaller than the brain, but in animals, on the contrary, it is much larger. This is due to the fact that in animals the jaws are an organ of defense and acquisition of food and are therefore well developed, and the volume of the brain is less than in humans.

The bends of the spine, associated with the movement of the center of gravity due to the vertical position of the body, help a person maintain balance and soften shocks. Animals do not have such bends.

The human chest is compressed from front to back and close to the spine. In animals it is compressed from the sides and extended towards the bottom.

The wide and massive human pelvic girdle has the shape of a bowl and supports the organs abdominal cavity and transfers body weight to the lower limbs. In animals, body weight is evenly distributed between the four limbs and the pelvic girdle is long and narrow.

The bones of the lower limbs of humans are noticeably thicker than the upper ones. In animals there is no significant difference in the structure of the bones of the fore and hind limbs. Greater mobility of the forelimbs, especially the fingers, allows a person to perform a variety of movements and types of work with his hands.

Skeleton of the torso axial skeleton

Skeleton of the torso includes a spine consisting of five sections, and the thoracic vertebrae, ribs and sternum form chest(see table).

Scull

In the skull there are brain and facial sections. IN brain The section of the skull - the cranium - contains the brain, it protects the brain from blows, etc. The skull consists of fixedly connected flat bones: the frontal, two parietals, two temporal, occipital and sphenoid. The occipital bone is connected to the first vertebra of the spine using an ellipsoidal joint, which allows the head to tilt forward and to the side. The head rotates along with the first cervical vertebra due to the connection between the first and second cervical vertebrae. IN occipital bone there is an opening through which the brain connects to the spinal cord. The floor of the skull is formed by the main bone with numerous openings for nerves and blood vessels.

Facial the skull section forms six paired bones - upper jaw, zygomatic, nasal, palatine, lower turbinate, as well as three unpaired bones - the lower jaw, vomer and hyoid bone. The mandibular bone is the only bone of the skull that is movably connected to temporal bones. All bones of the skull (except lower jaw), are connected motionlessly, which is due to the protective function.

The structure of the human facial skull is determined by the process of “humanization” of the monkey, i.e. the leading role of labor, the partial transfer of grasping function from the jaws to the hands, which have become organs of labor, the development of articulate speech, the consumption of artificially prepared food, which facilitates the work of the masticatory apparatus. Brain skull develops in parallel with the development of the brain and sensory organs. Due to the increase in brain volume, the volume of the cranium has increased: in humans it is about 1500 cm2.

Skeleton of the torso

The skeleton of the body consists of the spine and rib cage. Spine- the basis of the skeleton. It consists of 33–34 vertebrae, between which there are cartilage pads - discs, which gives the spine flexibility.

The human spinal column forms four curves. In the cervical and lumbar spine they are convexly facing forward, in the thoracic and sacral spine - backward. In the individual development of a person, bends appear gradually; in a newborn, the spine is almost straight. First, the cervical curve forms (when the child begins to hold his head straight), then the thoracic curve (when the child begins to sit). The appearance of lumbar and sacral curves is associated with maintaining balance in an upright position of the body (when the child begins to stand and walk). These bends have important physiological significance - they increase the size of the thoracic and pelvic cavities; make it easier for the body to maintain balance; soften shocks when walking, jumping, running.

With the help of intervertebral cartilage and ligaments, the spine forms a flexible and elastic column with mobility. She is not the same different departments spine. The cervical and lumbar regions spine, less mobile thoracic region, since it is connected to the ribs. The sacrum is completely motionless.

There are five sections in the spine (see diagram “Divisions of the spine”). The size of the vertebral bodies increases from the cervical to the lumbar due to greater load to the underlying vertebrae. Each vertebrae consists of a body, a bony arch and several processes to which muscles are attached. There is an opening between the vertebral body and the arch. The foramina of all vertebrae form spinal canal where the spinal cord is located.

Rib cage formed by the sternum, twelve pairs of ribs and thoracic vertebrae. It serves as a container for important internal organs: heart, lungs, trachea, esophagus, large vessels and nerves. Takes part in breathing movements due to the rhythmic rise and fall of the ribs.

In humans, in connection with the transition to upright walking, the hand is freed from the function of movement and becomes an organ of labor, as a result of which the chest experiences a pull from the attached muscles of the upper limbs; the insides do not press on the front wall, but on the lower one, formed by the diaphragm. This causes the chest to become flat and wide.

Skeleton of the upper limb

Skeleton of the upper limbs consists of the shoulder girdle (scapula and collarbone) and free upper limb. The scapula is a flat, triangular bone adjacent to the back of the rib cage. The collarbone has a curved shape, resembling Latin letter S. Its significance in the human body is that it sets the shoulder joint some distance from the chest, providing greater freedom of movement of the limb.

The bones of the free upper limb include the humerus, the bones of the forearm (radius and ulna) and the bones of the hand (bones of the wrist, bones of the metacarpus and phalanges of the fingers).

The forearm is represented by two bones - the ulna and the radius. Due to this, it is capable of not only flexion and extension, but also pronation - turning inward and outward. The ulna at the top of the forearm has a notch that connects to the trochlea of ​​the humerus. The radius bone connects to the head of the humerus. In the lower part the most massive end has radius. It is she who, with the help of the articular surface, together with the bones of the wrist, takes part in the formation of the wrist joint. On the contrary, the end ulna here it is thin, it has a lateral articular surface, with the help of which it connects to the radius and can rotate around it.

The hand is the distal part of the upper limb, the skeleton of which is made up of the bones of the wrist, metacarpus and phalanges. The carpus consists of eight short spongy bones arranged in two rows, four in each row.

Skeleton hand

Hand- the upper or forelimb of humans and monkeys, for which the ability to oppose was previously considered a characteristic feature thumb to everyone else.

The anatomical structure of the hand is quite simple. The arm is attached to the body through the bones of the shoulder girdle, joints and muscles. Consists of 3 parts: shoulder, forearm and hand. Shoulder girdle is the most powerful. Bending your arms at the elbow gives your arms greater mobility, increasing their amplitude and functionality. The hand consists of many movable joints, it is thanks to them that a person can click on the computer keyboard or mobile phone, point a finger in the right direction, carry a bag, draw, etc.

The shoulders and hands are connected through humerus, ulna and radius bones. All three bones are connected to each other using joints. At the elbow joint, the arm can be bent and extended. Both bones of the forearm are connected movably, so during movement in the joints, the radius rotates around the ulna. The brush can be rotated 180 degrees.

Skeleton of the lower limbs

Skeleton of the lower limb consists of the pelvic girdle and the free lower limb. The pelvic girdle consists of two pelvic bones, articulated posteriorly with the sacrum. The pelvic bone is formed by the fusion of three bones: the ilium, the ischium and the pubis. Complex structure This bone is determined by a number of functions it performs. Connecting to the thigh and sacrum, transferring the weight of the body to the lower limbs, it performs the function of movement and support, as well as a protective function. Due to the vertical position of the human body, the pelvic skeleton is relatively wider and more massive than that of animals, since it supports the organs lying above it.

The bones of the free lower limb include the femur, tibia (tibia and fibula) and foot.

The skeleton of the foot is formed by the bones of the tarsus, metatarsus and phalanges of the fingers. The human foot differs from the animal foot in its arched shape. The arch softens the shocks the body receives when walking. The toes in the foot are poorly developed, with the exception of the big one, as it has lost its grasping function. The tarsus, on the contrary, is highly developed, the calcaneus is especially large in it. All these features of the foot are closely related to the vertical position human body.

Human upright walking has led to the fact that the difference in the structure of the upper and lower limbs has become significantly greater. Human legs are much longer than arms, and their bones are more massive.

Bone connections

There are three types of bone connections in the human skeleton: fixed, semi-movable and mobile. Fixed type of connection is a connection due to fusion of bones (pelvic bones) or the formation of sutures (skull bones). This fusion is an adaptation to bear the heavy load experienced by the human sacrum due to the vertical position of the torso.

Semi-movable the connection is made using cartilage. The vertebral bodies are connected in this way, which contributes to the tilt of the spine different sides; ribs with the sternum, which allows the chest to move during breathing.

Movable connection, or joint, is the most common and at the same time complex form of bone connection. The end of one of the bones that forms the joint is convex (the head of the joint), and the end of the other is concave (the glenoid cavity). The shape of the head and socket correspond to each other and the movements carried out in the joint.

Articular surface The articulating bones are covered with white shiny articular cartilage. The smooth surface of articular cartilage facilitates movement, and its elasticity softens the shock and shock experienced by the joint. Usually articular surface one bone forming the joint is convex and is called the head, the other is concave and is called the socket. Thanks to this, the connecting bones fit tightly to each other.

Bursa stretched between the articulating bones, forming a hermetically sealed joint cavity. The joint capsule consists of two layers. The outer layer passes into the periosteum, the inner layer releases fluid into the joint cavity, which acts as a lubricant, ensuring free sliding of the articular surfaces.

Features of the human skeleton associated with work and upright posture

Labor activity

The body of a modern person is well adapted to work and walking upright. Upright walking is an adaptation to the most important feature of human life - work. It is he who draws a sharp line between man and higher animals. Labor had a direct impact on the structure and function of the hand, which began to influence the rest of the body. The initial development of upright walking and the emergence of work activity entailed further changes in everything human body. The leading role of labor was facilitated by the partial transfer of the grasping function from the jaws to the hands (which later became organs of labor), the development of human speech, and the consumption of artificially prepared food (facilitates the work of the masticatory apparatus). The cerebral part of the skull develops in parallel with the development of the brain and sensory organs. In this regard, the volume of the cranium increases (in humans - 1,500 cm 3, in apes - 400–500 cm 3).

Upright walking

A significant part of the characteristics inherent in the human skeleton is associated with the development of bipedal gait:

• supporting foot with a highly developed, powerful big toe;
• hand with a very developed thumb;
• the shape of the spine with its four curves.

The shape of the spine was developed thanks to a springy adaptation to walking on two legs, which ensures smooth movements of the body and protects it from damage during sudden movements and jumps. The body in the thoracic region is flattened, which leads to compression of the chest from front to back. Lower limbs also underwent changes in connection with upright posture - widely spaced hip joints give stability to the body. During evolution, a redistribution of body gravity occurred: the center of gravity moved down and took a position at the level of 2–3 sacral vertebrae. A person has a very wide pelvis, and his legs are widely spaced, this allows the body to be stable when moving and standing.

In addition to the curved spine, the five vertebrae of the sacrum, and the compressed chest, one can note the elongation of the scapula and the expanded pelvis. All this entailed:

• strong development of the pelvis in width;
• fastening the pelvis to the sacrum;
• strong development and special way strengthening the muscles and ligaments in the hip area.

The transition of human ancestors to upright walking entailed the development of the proportions of the human body, distinguishing it from monkeys. Thus, humans are characterized by shorter upper limbs.

Upright walking and work led to the formation of asymmetry in the human body. Right and left half The human body is not symmetrical in shape and structure. A striking example this is the hand of man. Most people are right-handed, and about 2–5% are left-handed.

The development of upright walking, which accompanied the transition of our ancestors to living in open areas, led to significant changes in the skeleton and the entire body as a whole.

The musculoskeletal system ensures movement and maintaining the position of the animal’s body in space, forms external form body and participates in metabolic processes. It accounts for about 60% of the body weight of an adult animal.
Conventionally, the musculoskeletal system is divided into passive and active parts. The passive part includes bones and their connections, on which the nature of the mobility of bone levers and links of the animal’s body depends (15%). The active part is skeletal muscles and their auxiliary devices, thanks to the contractions of which, the bones of the skeleton are set in motion (45%). Both active and passive parts have a common origin (mesoderm) and are closely interconnected.

Functions of the movement apparatus:

1) Motor activity is a manifestation of the vital activity of an organism, it is what distinguishes animal organisms from plant organisms and determines the emergence of a wide variety of methods of movement (walking, running, climbing, swimming, flying).
2) The musculoskeletal system forms the body shape - the exterior of the animal, since its formation took place under the influence of the Earth’s gravitational field, its size and shape in vertebrates are characterized by significant diversity, which is explained by the different conditions of their habitat (terrestrial, ground-woody, air , water).
3) In addition, the movement apparatus provides a number of vital functions of the body: searching and capturing food; attack and active defense; carries out respiratory function lungs (respiratory motility); helps the heart in moving blood and lymph through the vessels (“peripheral heart”).
4) In warm-blooded animals (birds and mammals), the movement apparatus ensures the preservation constant temperature bodies;
The functions of the movement apparatus are provided by the nervous and cardiovascular systems, respiratory, digestive and urinary organs, skin, endocrine glands. Since the development of the movement apparatus is inextricably linked with the development of the nervous system, when these connections are disrupted, first paresis occurs, and then paralysis of the movement apparatus (the animal cannot move). When decreasing physical activity a violation occurs metabolic processes and atrophy of muscle and bone tissue.
The organs of the musculoskeletal system have the properties of elastic deformations; when moving, mechanical energy arises in them in the form of elastic deformations, without which normal blood circulation and impulses of the brain and spinal cord cannot occur. The energy of elastic deformations in bones is converted into piezoelectric energy, and in muscles into thermal energy. The energy released during movement displaces blood from the vessels and causes irritation of the receptor apparatus, from which nerve impulses enter the central nervous system. Thus, the work of the movement apparatus is closely connected and cannot be carried out without the nervous system, and the vascular system, in turn, cannot function normally without the movement apparatus.

Skeleton

The basis of the passive part of the movement apparatus is the skeleton. Skeleton (Greek sceletos - dried, dried; lat. Skeleton) are bones connected in a certain order that form a solid frame (skeleton) of the animal’s body. Since the Greek word for bone is “os,” the science of the skeleton is called osteology.
The skeleton includes about 200-300 bones (Horse -207), which are connected to each other using connective, cartilage or bone tissue. The skeletal mass of an adult animal is 15%.
All functions of the skeleton can be divided into two large groups: mechanical and biological. Mechanical functions include: protective, support, locomotor, spring, anti-gravity, and biological functions include metabolism and hematopoiesis (hemocytopoiesis).
1) The protective function is that the skeleton forms the walls of body cavities in which vital organs are located. For example, the cranial cavity contains the brain, the chest contains the heart and lungs, and the pelvic cavity contains the genitourinary organs.
2) The supporting function is that the skeleton provides a support for muscles and internal organs, which, being attached to the bones, are held in their position.
3) The locomotor function of the skeleton is manifested in the fact that the bones are levers that are driven by muscles and ensure the movement of the animal.
4) The spring function is due to the presence in the skeleton of formations that soften shocks and shocks (cartilaginous pads, etc.).
5) The anti-gravity function is manifested in the fact that the skeleton creates support for the stability of the body rising above the ground.
6) Participation in metabolism, especially mineral metabolism, since bones are a depot of mineral salts of phosphorus, calcium, magnesium, sodium, barium, iron, copper and other elements.
7) Buffer function. The skeleton acts as a buffer that stabilizes and maintains a constant ionic composition of the internal environment of the body (homeostasis).
8) Participation in hemocytopoiesis. Located in the bone marrow cavities, red bone marrow produces blood cells. Weight bone marrow in relation to bone mass in adult animals is approximately 40-45%.

The spinal column is divided into 5 sections: cervical, thoracic, lumbar, sacral and caudal. The cervical region consists of the cervical vertebrae (v.cervicalis); thoracic region - from the thoracic vertebrae (v.thoracica), ribs (costa) and sternum (sternum); lumbar - from the lumbar vertebrae (v.lumbalis); sacral - from the sacral bone (os sacrum); caudal - from the caudal vertebrae (v.caudalis). The most complete structure has the thoracic section of the body, where there are thoracic vertebrae, ribs, and breast bone, which together form the chest (thorax), in which the heart, lungs, and mediastinal organs are located. In terrestrial animals, the tail is the least developed, which is associated with the loss of the locomotor function of the tail during the transition of animals to a terrestrial lifestyle.
The axial skeleton is subject to the following laws of body structure, which ensure the mobility of the animal. These include:
1) Bipolarity (uniaxiality) is expressed in the fact that all parts of the axial skeleton are located on the same axis of the body, with the skull on the cranial pole and the tail on the opposite pole. The sign of uniaxiality allows us to establish two directions in the animal’s body: cranial - towards the head and caudal - towards the tail.
2) Bilaterality (bilateral symmetry) is characterized by the fact that the skeleton, like the torso, can be divided by the sagittal, medial plane into two symmetrical halves (right and left), in accordance with this the vertebrae will be divided into two symmetrical halves. Bilaterality (antimerism) makes it possible to distinguish lateral (lateral, external) and medial (internal) directions on the animal’s body.
3) Segmentation (metamerism) lies in the fact that the body can be divided by segmental planes into a certain number of relatively identical metamers - segments. Metameres follow an axis from front to back. On the skeleton, such metameres are vertebrae with ribs.
4) Tetrapodium is the presence of 4 limbs (2 thoracic and 2 pelvic)
5) And the last regularity is, due to gravity, the location in spinal canal the neural tube, and under it the intestinal tube with all its derivatives. In this regard, the dorsal direction is marked on the body - towards the back and the ventral direction - towards the abdomen.

The peripheral skeleton is represented by two pairs of limbs: pectoral and pelvic. In the skeleton of the limbs there is only one pattern - bilaterality (antimerism). The limbs are paired, there are left and right limbs. The remaining elements are asymmetrical. On the limbs there are girdles (thoracic and pelvic) and a skeleton free limbs.

Skeletal phylogeny

In vertebrate phylogenesis, the skeleton develops in two directions: external and internal.
The exoskeleton performs a protective function, is characteristic of lower vertebrates and is located on the body in the form of scales or shell (turtle, armadillo). In higher vertebrates, the external skeleton disappears, but its individual elements remain, changing their purpose and location, becoming the integumentary bones of the skull and, located under the skin, connected with the internal skeleton. In phylo-ontogenesis, such bones go through only two stages of development (connective tissue and bone) and are called primary. They are not able to regenerate; if the skull bones are injured, they are forced to be replaced with artificial plates.
The internal skeleton performs mainly a supporting function. During development, under the influence of biomechanical load, it constantly changes. If we consider invertebrate animals, then their internal skeleton has the form of partitions to which muscles are attached.
In primitive chordates (lancelet), along with the septa, an axis appears - the notochord (cellular cord), covered with connective tissue membranes.
In cartilaginous fish (sharks, rays), cartilaginous arches are formed segmentally around the notochord, which later form vertebrae. The cartilaginous vertebrae, connecting to each other, form the spinal column, and the ribs are attached to it ventrally. Thus, the chord remains in the form of nuclei pulposus between the vertebral bodies. The skull is formed at the cranial end of the body and, together with the vertebral column, participates in the formation of the axial skeleton. Subsequently, the cartilaginous skeleton is replaced by a bone one, less flexible, but more durable.
In bony fishes, the axial skeleton is built from stronger, coarse-fibrous bone tissue, which is characterized by the presence of mineral salts and a random arrangement of collagen (ossein) fibers in the amorphous component.
With the transition of animals to a terrestrial lifestyle, amphibians form a new part of the skeleton - the skeleton of the limbs. As a result of this, in terrestrial animals, in addition to the axial skeleton, a peripheral one (the skeleton of the limbs) is also formed. In amphibians, as well as in bony fish, the skeleton is built of coarse fibrous bone tissue, but in more highly organized terrestrial animals (reptiles, birds and mammals), the skeleton is already built of lamellar bone tissue, consisting of bone plates containing collagen (ossein) fibers arranged in an orderly manner.
Thus, the internal skeleton of vertebrates goes through three stages of development in phylogenesis: connective tissue (membranous), cartilaginous and bone. Bones internal skeleton, going through all these three stages are called secondary (primordial).

Skeletal ontogeny

In accordance with the basic biogenetic law of Baer and E. Haeckel, in ontogenesis the skeleton also goes through three stages of development: membranous (connective tissue), cartilaginous and bone.
On the most early stage During the development of the embryo, the supporting part of its body is dense connective tissue, which forms the membranous skeleton. Then a notochord appears in the embryo, and around it, first a cartilaginous, and later a bony spinal column and skull, and then limbs begin to form.
In the prefetal period, the entire skeleton, with the exception of the primary integumentary bones of the skull, is cartilaginous and makes up about 50% of the body weight. Each cartilage has the shape of a future bone and is covered with perichondrium (a dense connective tissue membrane). During this period, ossification of the skeleton begins, i.e. formation of bone tissue in place of cartilage. Ossification or ossification (Latin os-bone, facio-do) occurs both from the outer surface (perichondral ossification) and from the inside (enchondral ossification). In place of the cartilage, coarse fibrous bone tissue is formed. As a result of this, in fruits the skeleton is built of coarse fibrous bone tissue.
Only in the neonatal period is coarse fibrous bone tissue replaced by more advanced lamellar bone tissue. During this period, special attention to newborns is required, since their skeleton is not yet strong. As for the notochord, its remains are located in the center of the intervertebral discs in the form of nuclei pulposus. Special attention During this period, it is necessary to pay attention to the integumentary bones of the skull (occipital, parietal and temporal), since they bypass the cartilaginous stage. Between them in ontogenesis, significant connective tissue spaces called fontanelles (fonticulus) are formed; only in old age do they completely undergo ossification (endesmal ossification).