Human skeletal system structure and composition of the skeleton. Anatomical human skeleton - torso, upper and lower limbs, head: structure with the name and function of the bones, photo in front, side, back, quantity, composition, parts, weight of bones, diagram, description.

Parts of the skeleton. In the human skeleton, departments are distinguished: head skeleton, torso and limbs.

The skeleton of the head includes the brain and facial skull (color, pl. X).

brain skull form bones: paired - parietal and temporal- and unpaired - occipital, sphenoid, frontal, ethmoid.

Sphenoid bone located at the base of the skull. It distinguishes the body, on the upper surface of which is located Turkishsaddle(Fig. 81, B). In its recess is pituitary- gland of internal secretion. On the sides of the body of the sphenoid bone are small and large wings.

AT ethmoid bone distinguish labyrinths, generators middle, superior turbinates and plates: orbital, involved in the formation of the eye socket, perpendicular, forming the nasal septum, lattice, through which the fibers of the olfactory nerve pass (Fig. 81, BUT).

facial skull educated maxillary, nasal, tearsny, zygomatic, palatine, lower nasal conchas,nickname, lower jaw and hyoid bones(color table X). The skull has only one movable connective bone - the lower jaw.

The frontal, temporal, sphenoid and maxillary bones have sinuses, opening into the nasal cavity and thus connecting with the external environment. Due to the presence of this connection, the sinuses are pneumatized, i.e. filled with air.

eye socket formed by bones: from above - the frontal and sphenoid, from below - the maxillary and zygomatic, from the outside - the sphenoid, frontal and zygomatic, from the inside - the lacrimal and ethmoid (color table X).

In the nasal cavity there are three nasal conchas: upper, middle and lower, between them are the nasal passages, where the sinuses open.

The skeleton of the body consists of the spine and chest (Fig. 82). Spine includes 33-34 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral and 4-5 fused coccygeal. Accordingly, allocate cervical, chest,lumbar, sacral and coccygeal sections of the spine.

Each vertebra is made up of bodies, arcs and processes(Fig. 81, D). Distinguish unpaired spinous process, paired transverse,upper and lower articular processes, extending from the arc. Between the posterior surface of the vertebral body and its arch is callnight hole. The vertebral foramina of all vertebrae form spinal canal, in which the spinal cord is located. On the upper and lower borders of the vertebral arch and body are clippings. Above and below the notches form the intervertebral foramen, in which the spinal ganglia are placed.

The vertebrae of different parts of the spine have differences.

So, the first cervical vertebra, called atlas, has the shape of a somewhat elongated ring (Fig. 81, AT). On its front surface there is a glenoid fossa for articulation with the second vertebra.

Second vertebra - epistrophy- It has odontoid, with the help of which articulation with the first vertebra is carried out (Fig. 81, G). Around the odontoid process, the atlas rotates along with the skull.

The thoracic vertebrae have costal semi-fossae above and below the lateral surface of the body for articulation with the head of the rib. The cervical and lumbar vertebrae have transverse costal processes.

Rib cage formed by the sternum and 12 pairs of ribs (Fig. 82). Rib - curved plate - has head, neck and tubercle(Fig. 81, E). The head and tubercle of the ribs articulate with the thoracic vertebrae. The anterior ends of the ribs are cartilaginous. Ribs from I to VII articulate with the sternum, VIII - IX join the overlying rib, the ends of the X, XI and XII pairs of ribs are in the abdominal muscles.

The sternum is made up of handles, bodies and xiphoid process (Fig. 82). The handle is connected to the clavicle by the I pair of ribs, II-VII pairs of ribs are articulated with the body of the sternum.

The limb skeleton consists of the free limb skeleton and the girdle skeleton.

Upper limb belt includes paired bones lopatki and clavicle. The blade has an axis that ends playmarginal process- acromion. It forms a joint with the collarbone. At one of the corners of the scapula there is an articular cavity for articulation, with the head of the humerus (Fig. 81, 3).

Rice. 81. Bones of the human skeleton:

BUT 3 - eye; 4 - labyrinths; B- wedge-shaped: / - body; 2 - big wing; 3 - small wing; AT (2) arcs; 3 2 - articular surface; D- cervical vertebra: / - body; 2 - transverse and 3 - spinous processes; 4 - vertebral foramen E- rib: / - head; 2 2 - ischial; 3 - pubic; 3 2 - osty; 3 - supraspinous pit; 4 - infraspinatus pit; 5 - akromnon

Bones of the human skeleton:

BUT- lattice (top view): / - perpendicular plate; 2 - perforated; 3 - eye; 4 - labyrinths; B- wedge-shaped: / - body; 2 - big wing; 3 - small wing; AT- atlas: anterior (/) and posterior (2) arcs; 3 - articular surface for the odontoid process; G - epistrophy: / - odontoid process; 2 - articular surface; D- cervical vertebra: / - body; 2 - transverse and 3 - spinous processes; 4 - vertebral foramen E- rib: / - head; 2 - neck; F - gas bone: / - ilium; 2 - ischial; 3 - pubic; 3 - scapula: / - coracoid process; 2 - osty; 3 - supraspinous pit; 4 - infraspinatus pit; 5 - akromnon

R is. 82. Human Skeleton:

/"- scull; 2 - clavicle; 3 - handle, 4 - body and xiphoid (5) process of the sternum; 6 - chest; 7 - spine; 8 - pelvic bones; 9 - sacrum; 10 - brachial bone; // - radius; 12 - elbow bone; 13 - wrist; 14 - metacarpus; 15 - phalanges of fingers; 16 - femur; 17 - patella; 18 - fibula; 19 - tibia bone; 20 - tarsus; 21 - metatarsus; 22 - phalanges of fingers.

Skeleton of the free upper limb comprises brachialbones, bones forearms and brushes(Fig. 82). The humerus articulates with its head with the scapula, and in its lower part forms elbow joint with bones of the forearm: elbow, located along the line of the little finger, and ray- along the line of the thumb. The lower end of the radius forms radiocarpal joint with three bones of the upper row of the wrist. Brush form bones wrist,metacarpus and phalanges of fingers. The wrist consists of 8 bones arranged in two rows. The top row includes scaphoid, semilunar, trihedral and pea-like bones, and the lower a lotcoal, trapezoid, capitate and hooked.

metacarpus forms five tubular bones. The skeleton of the fingers consists of phalanges: the second - fifth fingers have three phalanges, and the first finger has two.

Belt of the lower extremities form paired pelvic bones and sacrum. Each hip bone is made up of iliac, ischialNoah and pubic(Fig. 81, G). At the point of their convergence, acetabulum, where the femoral head enters to form pelviship joint. On the surface of the ilium there is an articular surface for articulation with the sacrum. The right and left pubic bones are connected in front, forming a semi-joint.

Skeleton of the free lower limb comprises thighs, shins and feet(Fig. 82). The femur in the lower epiphysis has lateral and medial condyle. The condyles are provided with articular surfaces with which they articulate patella and more-tibia, forming knee-joint:

The skeleton of the leg is composed of tibial and peroneal bones. At the upper end of the tibia there are two condyles that articulate with the condyles of the femur. Below and outside the lateral condyle of the tibia is the articular platform for articulation with the fibula. The lower end of the tibia connects to ram a bone that, on its outer side, has an articular surface for connection with the surface of the fibula. The lower ends of the fibula and tibia are fused motionless, between them and the talus is formed ankle joint.

The foot is made up of tarsus, metatarsus and phalanges fingers. The bones of the tarsus are arranged in two rows. The top row includes battering ramnuyu and heel bones, lower - first, second, third wedgeprominent and cuboid. Between these two rows is scaphoid bone. Thus, the total tarsus includes seven bones. The metatarsus contains five tubular bones. The skeleton of the first finger consists of two phalanges, and the second - fifth - of three.

STRUCTURE AND PROPERTIES OF SKELETAL MUSCLES

The structure, classification and significance of various muscles. Skeletal muscles are actively involved in the organization of movement. Any motor reaction of the body is carried out with the participation of muscles, which, turning the skeleton into a system of levers, contribute to the movement of the body in space.

In all muscles there are tendon head- the beginning of the muscle, the abdomen, consisting of muscle fibers, and the end of the muscle, called the tendon. Usually, a muscle is attached to two or more bones that form a joint, which allows it to produce one or another movement in this joint when it contracts. There are muscles in which there are several joints between the attachment of its beginning and end. With this nature of muscle attachment, its contraction causes simultaneous movement in all these joints.

Muscles can be simple and complex. In complex muscles, unlike simple ones, the abdomen is formed by several heads, which, starting from different bone points, then merge together (two-headed, three-headed and four-headed). Similarly, the tendon of a muscle can be divided into several parts and attached to different bones. The place of attachment of muscles, in addition to bones, can be skin, eyeball, etc.

The surface of the muscle is covered with fascia formed by dense connective tissue. Connective tissue is formed at the points of contact between two tendons or a tendon and a bone. sinovial bags, in which there is a small amount of fluid that reduces the friction of rubbing surfaces. In the places where the tendons pass in the bone canal, they are covered sinovial vaginas, inside which there is also a small amount of fluid, which, by removing friction, facilitates movement.

Rice. 83. Location of fibers in different muscles:

BUT- spindle-shaped; b - single-pinnate; AT R - two-feathered; G - wide.

Muscles are distinguished by function - | flexors, extensors, adductors and diverting muscles, as well as muscles rotating in and out

In long muscles, fibers can have: 1) a parallel arrangement, oriented along the long axis of the muscles; 2) parallel arrangement with respect to each other and oblique relative to the long axis of the abdomen; 3) oblique arrangement in relation to each other and to the long axis of the abdomen (Fig. 83). According to the location of the fibers, muscles are distinguished fusiformnye, semi-pinnate and pinnate. The semi-feathery and pennate muscles have shorter fibers than the fusiform ones, so the range of motion during their contraction is less. In the broad muscles, the fibers can be located in parallel (rhomboid muscles), radially and fan-shaped (pectoralis major muscle). Muscles in which the fibers are located radially can contract both as a whole and in their individual parts in directions that intersect various axes of movement in the joint. Therefore, they are located mainly in the region of spherical joints, which are characterized by high mobility.

Depending on the location of the muscles, they are divided into muscles head, neck, torso(chest, abdomen, back) muscle topthem, the lower limbs. The names of the muscles belonging to one or another group, and their location is given on color tables XI and XII.

Muscles of the head divided into chewing and mimic. Chewing muscles provide movements of the lower jaw, participate in the act of chewing; facial muscles, attaching to the skin of the face, they displace it during their contraction, which underlies mimic movements: wrinkling the eyebrows, raising and lowering the corners of the mouth, etc.

Neck muscles carry out its flexion and movement of the head, lower the lower jaw, raise the ribs, participate in breathing, displace the hyoid bone and larynx, can fix the hyoid bone and thereby contribute to the appearance of sounds in the larynx.

chest muscles, located superficially, set in motion the shoulder girdle and arm; those located more deeply, contracting, carry out a respiratory act.

Abdominal muscles contribute to exhalation, cause the spine to bend forward, to the side and rotate it around the longitudinal axis. They form the wall of the abdominal cavity - the abdominal press, contribute to the excretion of urine, feces, etc.

back muscles, located superficially, cause the movement of the arm, the belt of the upper limbs, the extension of the head, the fixation of the scapula.

More deeply located back muscles are involved in respiratory movements, cause extension of the spine, tilt it to the side and rotation, extension and rotation of the head, and provide fixation of the spine.

Human skeleton at birth it consists of approximately 350 bones. During the development and growth of the body, some of them grow together, so the skeleton of an adult contains 206 bones. All bones of the skeleton can be divided into two groups: the first - the axial skeleton - the supporting structure of the body, the second - the additional skeleton. People also have manifestations of the exoskeleton (external skeleton) - teeth, nails, hair, well-developed invertebrates. Fully developed bone - the hardest tissue in the body - consists of water (20%), organic material (30-40%) and inorganic material (40-50%).

Growth and development of bones

Most of the bones are formed from cartilage. The latter is calcified (calcified) and ossified (ossified), thus forming a true bone. In this process, the following stages are distinguished:

1. Activation during the first trimester of pregnancy (the second and third months of embryonic development) of bone-forming cells - osteoblasts.

2. Production of matrix by osteoblasts. The matrix is ​​the material between cells. It consists of a large amount of collagen (a fibrous protein) that strengthens the tissue. Further, the deposition of calcium in the intercellular substance is provided by enzymes.

3. Strengthening around the cells of the intercellular substance. The cells become osteocytes, that is, living cells. They do not produce new bone, but make up the stroma of the bone.

4. Destruction, reconstruction, restoration of bone by osteoclasts throughout life. With age, these processes slow down. That is why in older people the bones become more fragile and weak.

Osteoblasts and osteoclasts are involved in building and breaking down bone. Thanks to these cells, the bones slowly but adapt to the needs of the body in terms of shape and strength.
This is how the secondary bones of the skeleton develop. The primary bones of the skeleton (or integumentary) develop without a cartilaginous stage. These are most of the bones of the face, the bones of the cranial vault and parts of the clavicle.

Cartilage

Cartilage(cartilage) may exist as a temporary formation, later replaced by bone, or as a permanent addition to bone. Bone is denser and stronger than cartilage.

Cartilage is made up of living cells called chondrocytes. They are located in lacunae and are surrounded by collagen-rich intercellular substance. The cartilage is almost not permeated with blood vessels, that is, it is a relatively avascular structure. Cartilage is nourished mainly from the surrounding tissue fluid. Cartilage is divided into three main types: hyaline, white fibrous and yellow fibrous cartilage.

Serves as a temporary basis for the development of many bones. In the future, it remains next to the bone in the following forms:

Articular cartilage of the synovial joint.

Cartilaginous plates located between separately ossified zones of the bone during the growth period.

The xiphoid process of the sternum, ossifying later or not ossifying at all, and costal cartilages.

Also, hyaline cartilage is found in the nasal septum, in most cartilages of the larynx, in the rings of the bronchi and trachea.

Consists of white fibrous tissue. Compared with hyaline cartilage, the white fibrocartilage tissue will be more elastic and stronger. Fibrous cartilage contains:

Sesamoid cartilages of some tendons.

Articular discs of the clavicular and carpal joints.

Frame (lip) of the articular cavities of the shoulder and femoral joints.

Two semilunar cartilages in the knee joints.

Intervertebral discs located between adjacent surfaces of the vertebral bodies.

Lamellar cartilage that connects the pelvic bones at the pubic joint.

AT yellow fibrocartilage contains yellow elastic fibers. It is found in the epiglottis, auricle and Eustachian tube of the middle ear.

Functions of bones

Support. Bones form a rigid bone-cartilaginous skeleton of the body, to which many internal organs, muscles, and fascia are attached.

Protective. Bone receptacles are formed from bones to protect the brain (skull), spinal cord (spine), vital organs (rib frame).

Motor. The use of bones by muscles as levers to move the body, due to the presence of movable tendons. Muscles also determine the coherence of the possible movements of bones and joints.

Cumulative. Long bones (central cavities) store fat in the form of yellow bone marrow. Bone tissue plays an important role in metabolism, due to the accumulation of minerals - the main ones - calcium and phosphorus, as well as additional ones - sulfur, copper, sodium, magnesium, potassium. When there is a need in the body for any of these substances, they can be released into the blood and distributed throughout the body.

Hematopoietic. In the red bone marrow of certain certain bones, new blood cells are formed - hematopoiesis occurs.

Bone types by density

compact bone

The compact bone forms a long diaphysis and epiphyses of tubular bones. On a transverse section of a compact bone, one can see an accumulation of osteops, or Haversian systems. Each of these systems is an elongated cylinder. It is oriented along the long axis of the bone, consists of a central Haversian canal and contains blood vessels that provide blood supply to the elements of the osteon, lymphatic vessels and nerves surrounded by concentric bone plates. Such plates are called plates. Between them there are gaps containing osteocytes and lymph. Through thin channels (lymphatic tubules in the Haversian canal), the lacunae communicate with each other. Lymphatic tubules provide osteocytes with nutrition from the lymph. Multiple tubular plates give great strength to the bone. At right angles to the long bone are perforated or Volkmann canals. Nerve fibers and blood vessels pass through them.

Cancellous bone (cancellous bone, ethmoid bone)

Spongy bone is formed in the epiphyses of long bones, vertebral bodies and other bones that do not have cavities. Consists of trabeculae (synonym: crossbar). They are tubular-connected osteocytes and randomly built plates. Spongy bone lacks Haversian systems, but has multiple open spaces in a cellular structure similar to large Haversian canals. These spaces are filled with blood vessels and yellow or red marrow. In this case, a dynamic lattice is formed. It is capable of gradual change by restructuring in response to muscle tension and the effects of weight.

Types of bones by shape

Asymmetric bones
Asymmetric bones are formed mainly by spongy bone covered with thin layers of compact bone and have a composite shape. These include the pelvic bones, vertebrae, and some bones of the skull.

flat bones
Flat bones consist of spongy bone tissue lying between two thin layers of compact bone. They are thin, often curved, flattened. These include most of the bones of the skull, ribs, and sternum.

short bones
Short bones are formed mainly by spongy bone tissue and have a cubic shape. These include the bones of the wrist and the bones of the tarsus.
Among short bones, sesamoid bones are distinguished separately. Their name is derived from the Latin word, which means “formed, just like a sesame seed”). They are formed and located within the tendon. These include the patella (patella) and the pisiform bone at the medial end of the carpal crease.

long bones
Long bones are composed primarily of compact bone. They have a diaphysis with epiphyses at both ends. These include the bones of the limbs, except for the bones of the hand and foot.

In the center of the diaphysis, the transformation of the cartilage of the long bone begins. Later, secondary bone-forming centers form at the ends of the bones, from which bone growth occurs during childhood and adolescence, ending only at the beginning of the age of twenty. After that, the growth zones are compacted.

diaphysis(Greek - "separation")
The diaphysis is the central part of a long bone. It consists of a bone marrow-filled cavity surrounded by dense bone tissue. The diaphysis is formed from one or more primary ossification sites and is supplied by one or more feeding arteries.

epiphysis(Greek - "outgrowth")
The epiphysis is the terminal part of a long bone, or any part of a bone separated from the main body by immature bony cartilage. The epiphysis is formed from the secondary site of ossification and consists mainly of cancellous bone.

epiphyseal line
The epiphyseal line is a remnant of the epiphyseal plate of hyaline cartilage. Found in young, growing bone. It is the growth zone of a long bone. Gradually, in the adult state, the plate is completely replaced by bone, and the growth of long bones stops. Only the residual line indicates its previous location.

articular cartilage
Articular cartilage is located within the synovial joint at the points where two bones touch. It is smooth, slippery, porous, flexible, insensitive and avascular. Massaged with movements that promote the absorption of synovial fluid, oxygen and nutrients.
Note: Articular cartilage can be destroyed due to the degenerative process in osteoarthritis and advanced stages of some forms of rheumatoid arthritis.

Periosteum
The periosteum is a fibrous membranous connective tissue. The periosteum forms a two-layer membrane that envelops the outer surface of the bone. The shell is highly sensitive. The outer layer is formed by dense irregular connective tissue. The inner layer is composed of osteoblasts and osteoclasts and is directly opposite the surface of the bone.
In the periosteum there are lymphatic and blood vessels that penetrate the bone through the nutrient channels, and nerve fibers. The periosteum is attached to the bone by Sharpei fibers, which are made of collagen. The periosteum also forms attachment points for tendons and ligaments.

medullary cavity
The medullary cavity is the cavity of the diaphysis containing the bone marrow. In young people, it is red, turning into yellow marrow in most bones with age.

red bone marrow
Red bone marrow is a red gelatinous substance. It consists of red and white blood cells at different stages of development. It is located in the bone marrow cavities of flat and long bones, in their spongy part. In people who have reached puberty, red bone marrow, which produces new red blood cells, is found in flat bones (sternum), asymmetrical bones (pelvic), in the heads of the femur and humerus. If hemolytic disease is suspected, red bone marrow samples can be obtained from these bones.

yellow bone marrow
The yellow bone marrow is not capable of producing blood cells, as it is a fatty connective tissue.

1.Protrusions on the bones at the points of attachment of muscles and ligaments

skewer
The protrusion on the thigh is not symmetrical, very large, obtuse.

ledges
Large rounded protrusions with a rough surface. They are located mainly on the ischium - the tubercle of the ischium and on the lower leg - the tubercle of the tibia.

tubercles
Smaller protrusions with a rough surface.

Crest
A narrow protrusion of bone, often protruding forward. Example: iliac crest.

Border (border)
A narrow protrusion of bone that serves to separate two surfaces.

spinous process
Sharp, narrow, usually well visible from the outside: spinous processes of the vertebrae; the iliac spine or scapula (anterior superior iliac spine, ASIS, and posterior superior iliac spine, PSIS).

epicondyle
Raised area above the condyle; especially on the humerus at the elbow joint.

2. Protrusions on the bones involved in the formation of joints

Head
An extension, usually round in shape, is located at one end of the bone. An example is the head of the fibula, which connects to the tibia below the knee joint.

Articular facet
An almost flat, smooth surface at one end of a bone that is connected to another bone.

condyle
A large rounded bulge or protrusion of the epiphysis. Connects to another bone (located in the knee joint).

3. Recesses and openings for the passage of blood vessels and nerves

Sinus
An air-filled and sheathed bony cavity (found only in the skull).

fossa
An indentation in a bone that usually acts as an articular surface. The pits are shallow and bowl-shaped.

Hole
An oval or round hole in a bone (such as the sacrum).

The human skeleton is divided into torso skeleton, head skeleton, limb skeleton and their belts.

Torso skeleton

Torso skeleton includes the spine and thorax. formed by 33-34 vertebrae located one above the other. Between the vertebral bodies are layers of cartilage, giving the spine flexibility and elasticity.

There are five sections of the spine: cervical, consisting of 7 vertebrae, chest- out of 12, lumbar- out of 5, sacral- from 5 and coccygeal(caudal) - from 4–5 fused vertebrae. Each vertebra is made up of body, arcs and processes. There is a hole between the body and the arc.

The vertebral foramina together form spinal canal, in which lies spinal cord. The first two cervical vertebrae provide rotation of the head. The most massive vertebrae are located in the lumbar region, which bears the greatest weight of the body. The sacral vertebrae fuse into a massive bone - sacrum. The coccygeal bones are underdeveloped and represent a rudiment of the tail of human animal ancestors.

Head skeleton

Head skeleton- the skull is made up of paired and unpaired bones, most of them are flat, connected to each other motionless - seams. In the skull are distinguished cerebral and facial departments. The brain section consists of eight bones: four of them are unpaired - occipital, wedge-shaped, lattice, frontal and two pairs parietal and temporal.

Occipital bone forms the back wall of the skull and its base, has a large occipital foramen, through which the spinal cord is connected to the brain. In the center of the base of the skull is placed sphenoid bone. frontal bone lies in front of the parietal and is part of the skull roof. It is characterized by frontal tubercles and superciliary arches.

Ethmoid bone It is built of thin bone plates, between which there are air cavities. temporal bones occupy the anterolateral sides of the brain skull. Parietal- form the middle of the skull roof. The facial section of the skull consists of 6 paired and 3 unpaired bones. Of these, the lower part - the only movable bone of the skull - is articulated by two heads of the articular process with the mandibular fossa of the temporal bone. The upper and lower jaws contain 16 cells each, in which the roots of the teeth are placed.

In addition to the jaw bones, in the facial region there are nasal bones, coulter- an unpaired bone involved in the formation of the nasal septum, lacrimal bones, zygomatic and palatine.

Upper limb skeleton

Upper limb skeleton consists of a shoulder girdle and free limbs - hands. Shoulder girdle formed by two paired bones: spatula and clavicle. Two triangular shoulder blades are located on the back of the chest and articulate with the humerus and sternum.

The skeleton of the upper limb is formed by the bones: brachial connected to the blade forearms(radial and ulnar) and brushes. The hand skeleton is formed small bones of the wrist, long bones of the pastern and finger bones. The bones of the forearm, together with the shoulder, make up a complex elbow joint, and with the bones of the wrist, the wrist joint.

The hand includes 8 small bones of the wrist arranged in two rows, five bones of the metacarpus forming the palm and fourteen phalanges of the fingers, of which the thumb has two phalanges, and the rest have three.

Skeleton of the lower extremities

Skeleton of the lower extremities is divided into the skeleton of the pelvic girdle and the skeleton of free limbs - legs.

Pelvic girdle consists of two massive flat pelvic bones, firmly fused to the sacrum at the back, and almost rigidly connected to each other in front in a false articulation. They have round depressions where the heads of the femurs enter.

The skeleton of the lower limb consists of bones: femoral, shins(tibia tibia and tibia) and feet. The knee joint - the junction of the thigh and lower leg - is protected in front by a small flat patella. The moaning skeleton is formed by the short bones of the tarsus, the long bones of the metatarsus, and the phalanges of the fingers. In connection with the upright posture, the human foot has acquired an arched shape, which gives it the properties of a spring and provides a springy gait.

Features of the human skeleton associated with upright posture and labor activity - 4 smooth curves of the spine, a wide chest, massive bones of the lower extremities, wide pelvic bones, arched foot, the predominance of the cerebral part of the skull over the facial.

The following sections are distinguished in the human skeleton: the skeleton of the body, the skeleton of the upper and lower extremities, and the skeleton of the head - the skull (see Fig. 13). There are more than 200 bones in the human body.

Torso skeleton

The skeleton of the body consists of the spinal column and the skeleton of the chest.

vertebral column

vertebral column, or spine(columna vertebralis) (Fig. 18), is the support of the body, it consists of 33 - 34 vertebrae and their connections. Five sections are distinguished in the spine: cervical - 7 vertebrae, thoracic - 12, lumbar - 5, sacral - 5 and coccygeal - 4 - 5 vertebrae. The sacral and coccygeal vertebrae in an adult are fused and represent the sacral and coccygeal bones.

Vertebra(vertebra) consists of body and arcs, from which 7 processes depart: spinous, 2 transverse and 4 articular - two upper and two skin (Fig. 19). The vertebral body faces anteriorly, and the spinous process posteriorly. Body and arc limit spinal foramen. The vertebral foramina of all vertebrae are spinal canal in which the spinal cord is located. On the arches of the vertebrae there are recesses - the upper and lower notches. Notches of neighboring vertebrae form intervertebral foramen through which the spinal nerves pass.

The vertebrae of different parts of the spinal department differ in their structure.

Cervical vertebrae in the transverse processes they have openings through which the vertebral artery passes. The spinous processes of the cervical vertebrae are bifurcated at their ends.

I cervical vertebra - atlas- differs in that it does not have a body, but there are two arcs - anterior and posterior; they are interconnected by lateral masses. With its upper articular surfaces, which are in the form of pits, the atlas articulates with the occipital bone, and the lower, flatter ones, with the II cervical vertebra.

II cervical vertebra - axial- has an odontoid process that articulates with the anterior arch of the atlas. In the VII cervical vertebra, the spinous process is not bifurcated, protrudes above the spinous processes of neighboring vertebrae and is easily palpable.

Thoracic vertebrae(see Fig. 19) have articular fossae on the body for the heads of the ribs and on the transverse processes for the tubercles of the rib. In the thoracic vertebrae, the spinous processes are the longest downwards, they are directed backwards and downwards.

Lumbar vertebrae- the most massive, their spinous processes are directed straight back.

sacrum, or sacrum (sacrum) (Fig. 20), consists of 5 fused vertebrae. On the sacrum, the upper wide part is distinguished - the base, the lower narrow - the top and two side parts. The anterior, or pelvic, surface of the sacrum is concave and has four pairs of anterior sacral foramens. The posterior surface of the sacrum is convex, it distinguishes bony protrusions - ridges formed as a result of fusion of the processes of the vertebrae, and four pairs of posterior sacral foramens. Nerves pass through the sacral foramen. Inside the sacrum there is a sacral canal, which is a continuation of the spinal canal. At the junction of the sacrum with the V lumbar vertebra, a protrusion is formed in front - cape(promontoriurn). On the lateral parts of the sacrum, ear-shaped articular surfaces are distinguished, which serve to connect with the pelvic bones.

coccygeal bone, or coccyx (coccygeus), consists of 4 - 5 underdeveloped fused vertebrae and is a remnant of the tail that human ancestors had.

Spine connections. The vertebrae are interconnected through cartilage, joints and ligaments. The vertebral bodies are fused with cartilage. These cartilages are called intervertebral discs. The anterior and posterior longitudinal ligaments run along the anterior and posterior surfaces of the vertebral bodies throughout the spinal column. The joints of the vertebrae are formed by articular processes and are called intervertebral; according to the shape of the articular surfaces, they are referred to as flat joints. Ligaments exist between the arches of the vertebrae (yellow ligaments), the transverse processes (intertransverse ligaments), and the spinous processes (interosseous ligaments). The tops of the spinous processes are connected by a supraspinous ligament, which in the cervical spine is called the vulva.

The anterior and posterior atlanto-occipital membranes are stretched between the arches of the atlas and the occipital bone. The superior articular fossae of the 1st cervical vertebra form a paired atlanto-occipital joint of an ellipsoid shape with the occipital bone. In this joint, slight flexion and extension and tilt to the sides are possible. Between the I and II cervical vertebrae there are three joints in which the rotation of the atlas (together with the head) around the odontoid process of the II cervical vertebra is possible.

In the spine, flexion and extension, tilt to the sides and twisting are possible. Its most mobile department is the lumbar, and then the cervical.

Curves of the spine. The spinal column of a newborn is almost straight. As the child develops, the curves of the spine are formed. Distinguish the bends facing the bulge forward - lordosis and bulging back - kyphosis. There are two lordosis - cervical and lumbar and two kyphosis - thoracic and sacral. These bends are a normal phenomenon associated with the vertical position of a person and have a mechanical significance: they reduce the shaking of the head and trunk during walking, running and jumping. Most people have a slight curvature of the spine to the side - scoliosis. Pronounced scoliosis is the result of painful (pathological) changes in the spine.

Skeleton breast cage

The skeleton of the chest is formed from the connection of the sternum, 12 pairs of ribs and thoracic vertebrae (Fig. 21).

breast bone, or sternum(sternum), - a flat bone, in which three parts are distinguished: the upper one - the handle, the middle one - the body and the lower one - the xiphoid process. The handle is connected to the body at an obtuse angle protruding anteriorly.

On the upper edge of the sternum there is a so-called jugular notch, on the lateral edges - notches for the clavicles and 7 pairs of ribs.

In medical practice, they resort to a puncture (puncture) of the sternum, through which red bone marrow is removed from the spongy substance of this bone for microscopic examination.

Ribs(costae) are narrow flat curved bones (see Fig. 21). Each rib is made up of bone and cartilage. In the rib, there are: a body, two ends - anterior and posterior, two edges - upper and lower, and two surfaces - outer and inner. At the posterior end of the rib there is a head, neck and tubercle. On the inner surface of the rib at the lower edge there is a groove - a trace of the fit of nerves and blood vessels.

Humans have 12 pairs of ribs. The first rib differs from the others in that it lies almost horizontally. On its upper surface there is a scalene tubercle (the anterior scalene muscle is attached here) and two furrows - a trace of the subclavian artery and vein. The last two pairs of ribs are the shortest ribs. The ribs in the human body lie obliquely - their front ends are located below the rear.

Thoracic connections. The posterior ends of the ribs form joints with the thoracic vertebrae, with the heads of the ribs connected to the bodies of the vertebrae, and the tubercles to their transverse processes. In these joints, movement is possible - raising and lowering the ribs. The anterior ends of the seven upper pairs of ribs (I - VII pairs) are connected to the sternum with their cartilages. These edges are conditionally called true. The remaining five pairs of ribs (VIII - XII) do not connect with the sternum and are called false. Cartilages VIII, IX and X of the ribs are each attached to the cartilage of the overlying rib, forming a costal arch; The XI and XII pairs of ribs end freely in the muscles with their anterior ends.

Chest as a whole

Rib cage(thorax) serves as a container for important internal organs: the heart, lungs, trachea, esophagus, large vessels and nerves. Due to the rhythmic movements of the chest, its volume increases and decreases and inhalation and exhalation occur.

The size and shape of the chest depend on age, gender, and also have individual differences. The chest of an adult is compared in shape with a truncated cone; its transverse size is greater than the anteroposterior. The upper opening of the chest is limited by the first pair of ribs, the 1st thoracic vertebra and the jugular notch of the sternum. The lower opening is wider than the upper one, it is limited by the XII thoracic vertebra, XI and XII pairs of ribs, costal arches and the xiphoid process of the sternum.

The chest of the newborn has a pyramidal shape, its anteroposterior size is relatively larger than the transverse one, the ribs lie almost horizontally. Along with the growth of the chest in a child, its shape changes. The chest of a woman is smaller than that of a man. The upper part of the female chest is relatively wider than the male. The shape of the chest can change due to diseases. For example, in severe rickets, the chest is similar to a chicken breast (the sternum protrudes sharply anteriorly). Systematic physical education and sports from childhood contribute to the proper development of the chest and the whole body.

Upper limb skeleton

The skeleton of the upper limbs consists of the shoulder girdle and the skeleton of the free upper limbs (arms). The shoulder girdle consists of two pairs of bones - the clavicle and the scapula. The bones of the free upper limb (arm) include the humerus, the bones of the forearm and the bones of the hand. The bones of the hand, in turn, are subdivided into the bones of the wrist, metacarpus and phalanges of the fingers.

Bones and joints of the shoulder girdle

Collarbone(clavicula) has a curved shape resembling the letter S (see Fig. 21); consists of a body and two ends - sternal and acromial.

shoulder blade(scapula) - a flat triangular bone (Fig. 22). It distinguishes three edges (upper, medial and lateral), three corners (upper, lower and lateral), as well as the anterior and posterior surfaces, the coracoid and acromial processes and the articular cavity. The anterior surface faces the ribs, it has a recess - the subscapular fossa. A bony protrusion on the posterior surface of the scapula, called the scapular spine, divides this surface of the bone into two depressions - the supraspinous and infraspinatus fossae. The articular cavity of the scapula serves to connect with the humerus.

Joints of the bones of the shoulder girdle. The clavicle connects with its ends to the handle of the sternum and the acromial process of the scapula, forming two joints: sternoclavicular and acromioclavicular. The sternoclavicular joint is saddle-shaped in shape and has an intra-articular cartilage - a disk. In the joint, movements of the clavicle up and down, forward and backward are possible. The acromioclavicular joint is flat, with only slight displacement of the bones possible. Both joints are reinforced with ligaments. Between the acromial and coracoid processes of the scapula, a dense ligament is stretched, which is called the arch of the shoulder joint.

Bones and joints of the free upper limb (hand)

Brachial bone(humerus) is a long tubular bone. It consists of a body, or diaphysis, and two ends - epiphyses (Fig. 23). At the upper end, a head is distinguished that articulates with the scapula, the large and small tubercles, and the anatomical neck. Below the tubercles, the humerus is somewhat narrowed; this place is called the surgical neck (fractures of the humerus occur most often in this place). The body of the humerus has openings for the passage of blood vessels (nourishing orifices) and nerves, and roughness for attachment of the deltoid muscle.

At the lower end of the bone from the sides there are rough protrusions - the medial and lateral epicondyles. In addition, two articular surfaces for connection with the ulna and radius bones and two fossae are distinguished on it; coronal and ulnar.

Forearm bones. There are two bones of the forearm: the ulna and the radius. They are long tubular bones.

Elbow bone(ulna) on the forearm is located on the inside (Fig. 24). At its upper end there are the coronal and ulnar processes, the semilunar notch and tuberosity, at the lower end there is the head and styloid process.

Radius(radius) has a head with a fossa, a neck and tuberosity at the upper end, an articular surface for connection with the bones of the wrist and a styloid process at the lower end (see Fig. 24). The diaphyses of both bones of the forearm are trihedral; the sharpest edges of the bones face each other and are called interosseous.

Hand bones(ossa manus) subdivided into bones wrists, bones pastern and phalanges of fingers(Fig. 25).

There are eight bones of the wrist, they are arranged in two rows of four bones. The upper row is made up of the scaphoid, lunate, trihedral, and pisiform bones. The lower row includes two trapezoid bones - large and small, capitate and hooked bones. The bones of the wrist on the palmar side form a recess - the groove of the wrist, over which the transverse ligament is stretched. Between the ligament and the bones of the wrist there is a space - the canal of the wrist, in which the tendons of the muscles pass.

There are five bones of the metacarpus: the first, second, etc., the score is kept from the side of the thumb. They belong to tubular bones. Each metacarpal has a base, body, and head.

The bones of the fingers - phalanges - are relatively small tubular bones. The thumb has two phalanges - the main (proximal) and the nail (distal); on each of the other fingers there are three phalanges - the main (proximal), or first, middle, or second, and the nail, or third (distal).

Joints of the bones of the free upper limb (hand). The bones of the free upper limb are connected to each other through the joints. The largest of them are the shoulder, elbow and wrist.

shoulder joint(articulatio humeri) is formed by the articular cavity of the scapula and the head of the humerus (Fig. 26). In this joint, spherical in shape, movements are possible: flexion and extension, abduction and adduction, rotation and peripheral movement. The tendon of the long head of the biceps brachii passes through the joint.

elbow joint(articulatio cubiti) is formed by three bones: the humerus, ulna and radius. In this joint, three joints are united by a common articular bag: the shoulder-ulnar, shoulder-radial and radioulnar. The articular bag is reinforced with ligaments. In the elbow joint, movements are possible: flexion and extension.

Forearm bones are interconnected by an interosseous membrane and two radioulnar joints - proximal and distal, and the proximal is part of the elbow joint. Both joints are cylindrical in shape, rotation around the longitudinal axis is possible in them. At the same time, the movement of the brush occurs simultaneously with the radius. Rotation inward (palm back) is called pronation, rotation outward is called supination.

wrist joint(articulatio radiocarpea) connects the radius with the bones of the first row of the wrist (with the exception of the pisiform). In this joint, ellipsoid in shape, movements are possible: flexion and extension, abduction and adduction, as well as peripheral movement. The articular bag is reinforced with ligaments. The wrist joint and intercarpal joint (the joint between the two rows of bones in the wrist) are combined under the name of the hand joint.

On the brush The following joints are distinguished: intercarpal, flat in shape; carpometacarpal, also flat in shape; the exception is the joint between the large trapezoid bone and the first metacarpal bone - it has a saddle shape; metacarpophalangeal joints, spherical in shape; interphalangeal joints, blocky in shape. All joints of the hand are reinforced with ligaments.

The joints of the hand, especially the joints of the hand, are characterized by a significant scope and variety of movements. This is due to the fact that in the process of evolution, the forelimb of human ancestors turned into an organ of labor.

Skeleton of the lower extremities

The skeleton of the lower extremities consists of the pelvic girdle and the skeleton of the free lower extremities (legs). The pelvic girdle on each side is formed by an extensive pelvic bone.

The pelvic bones are connected to the sacrum and coccyx and together form the pelvis. The bones of the free lower limb include: the femur, the bones of the lower leg and foot. The bones of the foot, in turn, are subdivided into the bones of the tarsus, metatarsus and phalanges of the fingers.

Bones and joints of the pelvis

Pelvic bone(os coxae) fuses from three bones: ilium (os ilium), pubic (os pubis) and ischium (os ischii).

At the site of their fusion on the pelvic bone there is a recess - the acetabulum (Fig. 27), which includes the head of the femur.

On the ilium distinguish between body and wing. The edge of the wing is called the iliac crest; it ends with two protrusions - the anterior upper and posterior upper spines. Below these protrusions are the anterior lower and posterior lower spines, respectively. On the ilium there is also an arcuate line, an iliac fossa, gluteal lines and an ear-shaped articular surface.

Pubic bone consists of a body and two branches - upper and lower. On the upper branch there is a pubic tubercle and a pubic scallop. On the ischium distinguish between the body and the branch, the ischial tuberosity and the ischial spine. The ischial spine separates the greater ischial notch from the lesser. The branches of the pubic and ischial bones limit the obturator opening, which is covered almost completely by the connective tissue membrane.

Pelvis joints. The following pelvic joints are distinguished: 1) sacroiliac joint (paired): it is formed by the ear-shaped surface of the sacrum and ilium, strengthened by dense ligaments; this joint is flat in shape; 2) pubic fusion, or symphysis, - the connection of two pubic bones; the pubic bones are interconnected with the help of cartilage, inside of which there is a slit-like cavity (such a connection is called a half-joint); 3) proper ligaments of the pelvis - sacro-ospinous (between the sacrum and ischial spine) and sacro-tuberous (between the sacrum and ischial tuberosity). These ligaments, together with the sciatic notches, limit the foramen magnum and sciatica through which muscles, nerves, and blood vessels pass.

Taz in general

The pelvis (pelvis) is formed by two pelvic bones, the sacrum and coccyx and their joints (Fig. 28). It is customary to distinguish between a large and small pelvis. The boundary between them is called the boundary line; it passes through the promontory, along the arcuate lines of the iliac bones, the pubic scallops and along the upper edge of the symphysis. The large pelvis is bounded by the wings of the ilium. The small pelvis is formed by the pubic and ischial bones, the sacrum and the coccyx. In the small pelvis, there is an upper opening, or entrance, a cavity and a lower opening, or exit.

In the cavity of the small pelvis are the bladder, rectum and genital organs (in a woman - the uterus, fallopian tubes and ovaries, in a man - the prostate gland, seminal vesicles, vas deferens). The small pelvis in a woman is the birth canal. There are gender differences in the shape and size of the pelvis; the female pelvis is wider than the male, the wings of the ilium in women are more deployed, the promontory protrudes less into the pelvic cavity, the sacrum is wider and less curved. The angle under the symphysis between the lower branches of the pubic bones in men is less than a straight one, and in women it is obtuse and often represents an arc. In obstetric practice, knowledge of the size of the pelvis in women is of great importance. These sizes are individually different. Below are the most important from a practical point of view, the average dimensions of the female pelvis.

1. The distance between the anterior superior iliac spines is called the spinous distance (distantia spinarum), its size is 25 - 26 cm.

2. The distance between the most distant points of the iliac crests - scallop distance (distantia cristarum); it is 28 - 29 cm.

3. The distance between the large trochanters of the femur - intertrochanteric distance (distantia trochanterica); it is 30 - 31 cm.

4. The distance between the upper edge of the pubic fusion and the fossa corresponding to the gap between the V lumbar vertebra and the sacrum is the external conjugate or the direct size of the pelvis; this size is 20 - 21 cm. All of the listed dimensions are determined by external measurement of the pelvis with a special tool - a tazometer (a special compass).

5. The distance between the lower edge of the pubic fusion and the cape is the diagonal conjugate (conjugata diagonalis), its size is 12.5 - 13 cm. The diagonal conjugate is measured during a vaginal examination of a woman.

6. The distance between the cape and the most backward point on the inner surface of the pubic fusion - obstetric, or true, conjugate (10.5 - 11 cm). The obstetric conjugate is determined from the external conjugate by subtracting 9 cm or more accurately from the diagonal conjugate by subtracting 1.5 - 2 cm.

7. The distance between the lower edge of the pubic fusion and the tip of the coccyx is measured to determine the direct size of the outlet of the small pelvis. This distance is on average 11 cm. If we subtract 1.5 cm from this figure (they fall on the thickness of the coccyx and integuments), we get the direct size of the exit of the small pelvis - 9.5 cm. During childbirth, this size can increase to 11 cm due to coccyx mobility.

The size of the male pelvis is 1.5 - 2 cm smaller than the size of the female pelvis.

Bones and joints of the free lower limb

The femur (femur) is the longest tubular bone of the skeleton (Fig. 29). At its upper end there is a head, neck and two protrusions - large and small skewers. The body of the femur is cylindrical in shape, with a rough scallop on its posterior surface. At the lower end of the bone, two large protrusions are distinguished - the medial and lateral condyles, between which lies a recess - the intercondylar fossa. From the sides on the condyles there are protrusions - the medial and lateral epicondyles.

Patella cup, or patella (patella), has the shape of a triangle with rounded corners (see Fig. 13); it is adjacent to the lower end of the femur and is located in the tendon of the quadriceps femoris. Bones that develop in the tendons of the muscles are called sesamoid.

Lower leg bones. There are two bones of the lower leg - the tibia and the fibula; they belong to long tubular bones.

Tibia(tibia) is much thicker than the peroneal and is located on the lower leg from the inside (Fig. 30). At the upper end, it is distinguished by the medial and lateral condyles, the intercondylar eminence, two articular surfaces for articulation with the femur, the articular surface for articulation with the fibula, and tuberosity for muscle attachment. The body of the tibia is trihedral in shape, its front edge is called the crest. At the lower end of the tibia there is a protrusion called the ankle, and the articular surface for connection with the calcaneus.

Fibula(fibula) has at its upper end a head with an articular surface for connection with the tibia, at the lower end - an ankle with an articular surface for connection with the calcaneus (see Fig. 30).

Foot bones(ossa pedis) subdivided into bones tarsus, metatarsus and phalanges of fingers.

There are seven bones in the tarsus: the calcaneus, calcaneus, or talus, scaphoid, cuboid, and three cuneiform. On the heel bone there is a protrusion - the calcaneal tubercle. The mutual arrangement of the bones of the tarsus is shown in Fig. 31.

There are five metatarsal bones; they belong to tubular bones.

The bones of the toes (phalanges) are shorter than the corresponding phalanges of the fingers. Like the hand, the big toe has two phalanges, while the other fingers have three phalanges each.

Joints of the bones of the free lower limb (leg). The bones of the free lower limb are connected to each other through the joints. The largest joints are the hip, knee and ankle.

hip joint(articulatio coxae) is formed by the acetabulum of the pelvic bone and the head of the femur. In this joint, spherical (nut-shaped) in shape, movements are possible: flexion and extension, abduction and adduction, rotation and peripheral movement. Compared to the shoulder joint, movement in the hip joint is somewhat limited. The joint bag is strengthened by ligaments, the most powerful of them is called the ilio-femoral. It strengthens the joint capsule in front and is stretched between the anteroinferior iliac spine and the intertrochanteric line of the femur. The strong development of this ligament in humans is due to the vertical position of the body; it limits extension at the hip joint. Inside the joint there is a round ligament of the femoral head.

Knee-joint(articulatio genu) is formed by three bones: the femur, tibia and patella (Fig. 32). A feature of the joint is the presence of two intra-articular cartilage - menisci - and two intra-articular cruciate ligaments. The articular bag is reinforced with external ligaments. The synovial layer of the capsule forms folds inside the joint and protrusions in the form of synovial bags. The shape of the joint is block-rotational; movements are possible in it: flexion and extension, and in a bent position - a slight rotation of the lower leg.

Lower leg bones connected to each other by means of an interosseous membrane. In addition, the upper ends of these bones are connected by a flat joint, and the lower ends by a ligament.

Ankle joint(articulatio talocruralis), or the upper foot joint, is formed by the lower ends of the bones of the lower leg and the talus, and the ankles of the greater and fibula in the form of a fork cover the talus. The shape of this joint is blocky.

On the foot The following joints are distinguished: 1) subtalar, or talocalcaneal, joint - between the talus and calcaneus; 2) talocalcaneal-navicular joint; both joints together make up the lower foot joint; 3) the transverse joint of the tarsus, which combines two joints: the talonavicular and the calcaneus-cuboid; 4) the joint between the scaphoid, sphenoid and cuboid bones; 5) tarsus-metatarsal joints; they connect the sphenoid and cuboid bones with the metatarsal bones; 6) metatarsophalangeal joints; 7) interphalangeal joints. All joints of the foot are reinforced with strong ligaments.

The greatest movements are possible in the upper foot (ankle) and lower foot joints, which are combined under the name of the foot joint. In the upper foot joint, dorsiflexion (extension) and plantar flexion of the foot are possible. In the lower foot joint, pronation and supination of the foot are possible. During pronation, its outer edge is raised and the inner edge is lowered, while supination is the opposite. In this case, adduction and abduction of the foot also occur. Movements in the upper foot and lower foot joints can be combined.

Foot in general. The foot primarily functions as a support. The bones of the foot are not located in the same plane, but form bends in the longitudinal and transverse directions. These bends are convexly facing the back side, and concave in the plantar and are called arches of the foot. There are longitudinal and transverse vaults. When standing, the foot rests on the tubercle of the calcaneus and metatarsal heads. The presence of the arches of the foot causes a decrease in shocks during movements. Some people experience flattening of the arches of the foot, which is called flat feet and is a painful condition.

Head skeleton

The skeleton of the head is called skull(cranium). The skull (Fig. 33) has a cavity in which the brain is located. In addition, the bones of the skull form the skeleton of the oral cavity, nasal cavity and receptacles for the organ of vision (eye socket) and for the organ of hearing. Nerves and blood vessels pass through the numerous openings of the skull. It is customary to subdivide the skull into cerebral and facial departments. The bones of the brain section of the skull include two paired bones - the parietal and temporal, four unpaired - the frontal, ethmoid, occipital and sphenoid, the bones of the facial section of the skull - six paired bones - the upper jaw, zygomatic bone, nasal bone, lacrimal bone, palatine bone and the lower shell, as well as two unpaired bones - the vomer and the lower jaw. Together with the bones of the facial skull, the hyoid bone is considered. The bones of the skull have a different shape. A feature of the structure of some bones of the skull is the presence inside them of cavities filled with air. Air cavities have the upper jaw, ethmoid, frontal, sphenoid and temporal bones. Such cavities are called airways, or sinuses; they communicate with the nasal cavity, with the exception of the air-bearing cavities of the temporal bone, which communicate with the nasopharynx (through the auditory tube).

Skull bones

frontal bone(os frontale) consists of scales, two orbital parts and nasal part (Fig. 34). On the scales there are paired protrusions - frontal tubercles and superciliary arches. Each orbital part in front passes into the supraorbital region. The airy sinus of the frontal bone (sinus frontalis) is divided into two halves by the bony septum.

Ethmoid bone(os ethmoidale) consists of a horizontal, or perforated, plate, a perpendicular plate, two orbital plates and two labyrinths (see Fig. 36). Each labyrinth consists of small air cavities - cells separated by thin bone plates. Two curved bone plates hang from the inner surface of each labyrinth - the upper and middle turbinates.

Parietal bone(os parietale) has the shape of a quadrangular plate (see Fig. 33); on its outer surface there is a protrusion - the parietal tubercle.

Occipital bone(os occipitale) consists of scales, two lateral parts and the main part (Fig. 35). These parts define a large opening through which the cranial cavity communicates with the spinal canal. The main part of the occipital bone fuses with the sphenoid bone, forming a clivus with its upper surface. On the outer surface of the scales there is an external occipital protuberance. On the sides of the foramen magnum are the condyles, through which the occipital bone articulates with the atlas. At the base of each condyle passes the hypoglossal canal.

wedge-shaped, or main, bone(os sphenoidale) consists of a body and three pairs of processes - large wings, small wings and pterygoid processes (Fig. 36). On the upper surface of the body is the so-called Turkish saddle, in the fossa of which the pituitary gland is placed. At the base of the small wing there is an optic canal (optical opening).

Both wings (small and large) limit the superior orbital fissure. There are three holes on the large wing: round, oval and spinous. Inside the body of the sphenoid bone is the airway sinus, divided by a bony septum into two halves.

Temporal bone(os temporale) consists of three parts: scales, stony part, or pyramid, and drum part (Fig. 37).

The temporal bone contains the organ of hearing, as well as channels for the auditory tube, internal carotid artery and facial nerve. Outside on the temporal bone there is an external auditory meatus. Anterior to it is the articular fossa for the articular process of the lower jaw. The zygomatic process departs from the scales, which connects with the process of the zygomatic bone and forms the zygomatic arch. The rocky part (pyramid) has three surfaces: front, back and bottom. On its back surface is the internal auditory meatus, in which the facial and vestibulocochlear (stato-auditory) nerves pass. The facial nerve leaves the temporal bone through the awl-mastoid foramen. A long styloid process departs from the lower surface of the stony part. Inside the petrous part is the tympanic cavity (middle ear cavity) and the inner ear. The stony part also has a mastoid process (processus mastoideus), inside which are small air cavities - cells. The inflammatory process in the cells of the mastoid process is called mastoiditis.

The upper jaw (maxilla) (Fig. 38) consists of a body and four processes: frontal, zygomatic, palatine and alveolar. Four surfaces are distinguished on the body of the bone: anterior, posterior, or infratemporal, orbital, and nasal. On the front surface there is a recess - a canine fossa, on the back - a protrusion called the maxillary tubercle. The alveolar process contains eight recesses-cells in which the roots of the teeth are placed. Inside the body of the upper jaw there is an air cavity called the maxillary sinus.

Cheekbone(os zygomaticum) has the shape of an irregular quadrangle, forms a protrusion in the lateral part of the face and participates in the formation of the zygomatic arch (see Fig. 33).

nasal bone(os nasale) has the shape of a plate, participates in the formation of the back of the nose (see Fig. 33).

lacrimal bone(os lacrimale) - a small bone, has a lacrimal groove and a scallop, participates in the formation of the fossa of the lacrimal sac and the lacrimal canal (see Fig. 33).

palatine bone(os palatinum) consists of two plates: horizontal and vertical, participates in the formation of the hard palate and the side wall of the nasal cavity.

bottom sink is a thin curved bone plate, located on the side wall of the nasal cavity.

Coulter(vomer) has the shape of an irregular quadrangular plate, is involved in the formation of the nasal septum.

Lower jaw(mandibula) has the shape of a horseshoe, consists of a body and two branches (Fig. 39). The upper edge of the body is called the alveolar 1 , it contains 16 cells for the roots of the teeth. On the outer surface of the body there are two mental tubercles and two mental holes, on the inner surface - the chin protrusion and the maxillo-hyoid line. The branch of the jaw departs from the body at an obtuse angle and ends at the top with two processes: coronal and articular, separated by a notch. On the inner surface of the branch there is a mandibular foramen leading to the canal of the same name. The lower jaw is the only movable bone in the skull.

1 (Alveolus - hole, cell.)

Hyoid bone(os hyoideum) has the shape of a horseshoe and consists of a body and two pairs of horns (large and small). The hyoid bone is located between the lower jaw and the larynx, being the site of attachment of many muscles of the neck.

Joints of the bones of the skull

All bones of the skull, except for the lower jaw; connected by seams. The shape of the seams jagged, scaly and flat. An example of a jagged suture is the connection of the frontal bone with the parietal, scaly - the connection of the temporal bone with the parietal and flat - the connection of the bones of the facial skull. The most important sutures of the skull bear the following names: the suture between the frontal and parietal bones is called the coronoid, between the two parietal bones - sagittal, between the parietal and occipital bones - lambdoid. In older people, the sutures usually ossify.

temporomandibular joint(Fig. 40). The lower jaw is connected to the temporal bones through the combined temporomandibular joint. This joint has an intra-articular cartilage - a disk, the articular capsule is strengthened by ligaments. In the temporomandibular joint, the following movements of the lower jaw are possible: lowering and raising, displacement forward and backward, and displacement to the sides. All these movements are made during the act of chewing. The lowering and raising of the jaw occur during the pronunciation of sounds.

Skull as a whole

In the skull, as already noted, two sections are distinguished: cerebral and facial. The upper part of the brain is called roof, lower - basis skulls. The anterior part of the base of the brain region of the skull is covered from below by the bones of the facial skull. The scales of the frontal bone, parietal bones and the upper part of the scales of the occipital bone, as well as part of the scales of the temporal bone and the greater wing of the sphenoid bone participate in the formation of the skull roof. The bones of the roof of the skull are flat. They consist of outer and inner plates of compact substance, between which there is a spongy substance.

The base of the skull is formed by the frontal, occipital, sphenoid, ethmoid and temporal bones and has a complex structure. Distinguish outer and internal surface of the base of the skull.

On the outer surface of the base of the skull (Fig. 41), a large occipital foramen, condyles of the occipital bone, hyoid nerve canal, jugular foramen, styloid process, carotid canal opening, stylomastoid foramen, pterygoid processes of the sphenoid bone and other formations are visible. The inner surface of the base of the skull (Fig. 42) is divided into three cranial fossae: anterior, middle and posterior. It has the following parts and openings: perforated plate of the ethmoid bone, optic opening, superior orbital fissure, Turkish saddle, round, oval and spinous openings, the so-called torn opening, pyramid of the temporal bone, internal auditory canal and other formations.

On the inner surface of the bones of the brain skull, grooves are visible - a trace of the fit of the venous sinuses of the dura mater, as well as depressions and elevations - a trace of the convolutions and furrows of the brain.

On some bones of the skull there are holes that bear the names of venous graduates (on the parietal bone, mastoid process of the temporal bone, etc.). Through these holes, the venous sinuses of the hard shell and the veins of the bones of the skull communicate with the saphenous veins of the head.

On the side of the skull is the temporal, infratemporal and pterygopalatine fossa. temporal and infratemporal the pits are occupied by muscles, vessels and nerves. Pterygopalatine the fossa opens into the infratemporal fossa and, in addition, communicates with the cranial cavity through a round hole, with the nasal cavity - through the main palatine opening, with the orbit - the lower orbital fissure, with the oral cavity - the pterygopalatine canal. Nerves and blood vessels pass through the pterygopalatine fossa.

The bones of the facial skull form the skeleton of the oral cavity, nasal cavity and orbit.

Oral cavity(cavum oris) has upper and anterolateral bone walls. The upper wall is the hard palate, formed by the palatine processes of the maxillary bones and the horizontal plates of the palatine bones. The anterolateral walls of the oral cavity are formed by the alveolar processes of the jaws and teeth.

nasal cavity(cavum nasi) has a lower, upper and two side walls, as well as a partition. The bottom wall is the hard palate. From above, the nasal cavity is bounded by the nasal part of the frontal bone and the perforated plate of the ethmoid bone. The lateral wall is formed by the upper jaw, the vertical plate of the palatine bone and the labyrinth of the ethmoid bone. The nasal septum consists of a vomer and a perpendicular plate of the ethmoid bone; it divides the nasal cavity into right and left halves. Three curved bone plates extend from the side wall of the nasal cavity - shells (upper, middle and lower), which divide each half of the nasal cavity into three nasal passages: upper middle and lower. The nasal cavity on the skull has one anterior opening and two posterior ones. The anterior opening is called pear-shaped. The posterior openings are called choanae.

All the air-bearing sinuses of the bones of the skull open into the nasal cavity, with the exception of the air-bearing cells of the mastoid process.

eye socket(orbita) has four walls: upper, lower, outer and inner. The upper wall is formed by the orbital part of the frontal bone, the lower one by the orbital surface of the upper jaw, the outer one by the zygomatic bone and the greater wing of the sphenoid bone, and the inner one by the lacrimal bone and the orbital plate of the ethmoid bone. The optic opening and the superior orbital fissure lead from the orbit to the cranial cavity, the inferior orbital fissure leads to the pterygopalatine fossa, and the lacrimal canal leads to the nasal cavity.

The eye socket contains the eyeball and the lacrimal gland. The back of the eyeball is surrounded by fiber, in which the nerves and blood vessels pass, as well as the muscles of the eye.

Age features of the skull

The bones of the roof of the skull and all the bones of the facial skull, except for the lower shell, go through two stages in their development: membranous and bone. The remaining bones of the skull go through three stages: membranous, cartilaginous and bone. In the roof of the skull of a newborn there are unossified remains of a membranous skull, bearing the names of fontanelles (fonticuli) (Fig. 43). There are six springs in total: anterior, posterior, two wedge-shaped and two mastoid. The largest is the front, then the back. The anterior fontanel is located at the point of convergence of the sagittal suture with the coronal suture and has the shape of a rhombus. This fontanel ossifies by 1 1/2 years. The posterior fontanel is located at the posterior end of the sagittal suture, is much smaller than the frontal one, and ossifies by 2 months. The remaining fontanelles ossify shortly after birth.

Lesson topic

Human skeleton

Lesson Objectives

Continue to form schoolchildren's ideas about the structure of the human skeleton;
To consolidate students' knowledge about the human musculoskeletal system;

Lesson objectives

Continue to deepen the knowledge of students on the topic "Musculoskeletal system";
Focus the attention of children on the uniqueness of the structure of the human skeleton;
To consolidate the acquired knowledge through practical application, using reference materials and working with diagrams and tables;
Contribute to the formation of reflective qualities (introspection, self-correction);
Develop students' communication skills;
Favor the creation of a psychologically comfortable environment in anatomy lessons;
Raise students' interest in biology lessons.

Basic terms

The skeleton from the point of view of biology is such a biological system that is a reliable support for the human body.

The human skeleton in translation sounds like dried up, and denotes a set of hard bones in the body, which serve not only as a support for the body, but also for its individual parts, and also plays the role of protective functions of the body from various types of damage.

Bones are the components of the skeleton and its main elements.

Human skeleton

Even without studying anatomy, each of you knows that the human skeleton is made up of different bones, but what is its need ... We will try to figure this out together.

The skeleton is needed in order to support the body, protect the internal organs and keep the shape of the body. In addition to all of the above, strong muscles are attached to the skeleton.

First, thanks to the skeleton, a solid foundation is formed in which vulnerable parts of the body are located. It plays the role of a frame that is able to fix different parts of the body in a certain position. The bones of the chest act as protectors for the lungs and heart, and they have the ability to contract and expand as we breathe.

Secondly, the skeleton enables living beings to move. After all, nature was arranged in such a way that the skeleton consists of different bones, each of which has its own specific shape and performs a specific role in the human body. The mobility and flexibility of the skeleton to our body provide joints, cartilage and ligaments.

The number of bones in the human skeleton can be discussed for a very long time, since it is not the same for different people. Basically, the majority of the adult generation has more than 200 bones in the body. But it should be noted that there are people who are owners of an extra pair of ribs, others also have deviations in the number of vertebrae, and the skeleton of a newborn child has more than 350 types of bones. In addition, with age, some bones have the ability to grow together, and their number decreases. Therefore, it makes no sense to assert about a specific number of human bones, since it is not possible to make an accurate count.

Exercise:

1. Can human bones grow throughout life?
2. Why do bones sometimes lose their strength?
3. What should be done so that the bones do not lose their elasticity?

Organization of the skeleton

The human skeleton, like all vertebrates, is divided into an axial and accessory skeleton. The first includes all the bones that are located in the middle and create the skeleton of the body. These include all the bones of the head, neck, spine and ribs with the sternum. And the additional or peripheral skeleton includes the bones of the scapula, collarbone, as well as the bones of the upper and lower extremities.

Axial skeleton

Now let's take a closer look at the human axial skeleton.

Scull

The components of the skull are the bone base of the head, which protects the human brain and its organs of vision, hearing and smell. The skull is subdivided into the brain and facial sections and consists of flat and immovable bones, with the exception of the bones of the lower jaw.

To see what bones the brain and facial sections are made of, carefully consider the figure above.

And now look at the connection of the bones of the skull:

Exercise:

1. Name the bones that form the brain section?
2. Which of the bones of the skeleton of the skull are unpaired, and which are paired bones?
3. Name the largest bones that are located in the facial region.
4. Name all the bones that belong to the axial skeleton.
5. Which bone of the skull is immobile?

Torso skeleton

The skeleton of the human body consists of the chest and the spinal column. The thorax is the bone base of the chest, behind which the internal organs are hidden, and it consists of the sternum, twelve thoracic vertebrae and ribs.

The ribs of the human skeleton look like flat curved arcs, the posterior ends of which are connected to the thoracic vertebrae, and the anterior ones are connected to the sternum with the help of cartilage. Such fastening of the ribs to the skeleton creates conditions for the mobility of the chest during human breathing.

The spinal column is the main axis of the body, which is designed to support the human skeleton and is the main axis of the body. Inside the spine is the spinal cord.

The spinal column consists of 33-34 vertebrae, which is about forty percent of the length of the human body.

Four bends act as shock absorbers of the spine, which protect the internal organs and the brain, and soften shocks while walking, running and jumping.

peripheral skeleton

The accessory skeleton, or, as it is also called peripheral, consists of the skeleton of the limbs and is divided into the skeleton of the lower and upper limbs. The upper section includes the shoulder girdle and limbs, and the lower part includes the pelvic girdle with its limbs.

Since the free limbs are securely attached to the bones of the belt and have good mobility, they are able to withstand considerable loads.

Naturally, the upper and lower limbs have different functions. The upper ones provide a person with the opportunity to perform various movements and operations, while the lower ones are needed for movement and support.

Upper limb belt

The upper belt consists of the shoulder blades and collarbones. And the skeleton of the upper limbs is divided into the bones of the shoulder, forearm and hand.

Belt of the lower extremities

The pelvic girdle consists of three rigidly interconnected bones. In each such bone there is a spherical cavity, into which the head of the bone of the lower limb enters. The fixed bones of the girdle of the lower extremities, fused with the sacrum, provide the human body with reliable protection of the internal organs and allow it to withstand enormous physical exertion.

Skeleton of the lower extremities

If we consider the skeleton of the lower extremities, we can see that it consists of the femur, bones of the lower leg and foot. The femur and tibia have an anterior joint in the form of a patella, which provides mobility to the knee joint.

Homework

Look carefully at the drawing of the human skeleton and sign its digital designations:

Give answers to the questions posed:

1. Name all the departments that make up the human skeleton.
2. Name the number of vertebrae in each of the sections of the spine.
3. What parts does the spine consist of?
4. What is the significance of the curves of the spine for the human body?