All flat human bones. flat bones

Morphology, physiology and pathophysiology of the musculoskeletal system.

Movement is playing huge role in wildlife and is one of the main adaptive reactions to the environment external environment and a necessary factor in human development. The movement of a person in space is carried out thanks to the musculoskeletal system.

The musculoskeletal system is formed by bones, their joints and striated muscles.

Bones and their joints are the passive part of the musculoskeletal system, while muscles are the active part.

General anatomy of the skeleton. The human skeleton (skeletos) consists of more than 200 bones, 85 of them are paired, interconnected by means of a connective tissue with a different structure.

Skeleton Functions .

The skeleton performs mechanical and biological functions.

To mechanical functions skeleton include:

protection,

· motion.

The bones of the skeleton form cavities (vertebral canal, skull, chest, abdominal, pelvis) that protect the internal organs located in them from external influences.

Support is carried out by attaching muscles and ligaments to various parts of the skeleton, as well as maintaining internal organs.

Movement is possible in the places of movable joints of bones - in the joints. They are driven by muscles under the control of the nervous system.

to biological functions skeleton include:

The participation of bones in metabolism, especially in mineral metabolism - is a depot of mineral salts (phosphorus, calcium, iron, etc.)

Participation of bones in hematopoiesis. The function of hematopoiesis is performed by the red bone marrow contained in spongy bones.

Mechanical and biological functions mutually influence each other.

Each bone occupies a certain position in the human body, has its own anatomical structure and performs its functions.

The bone consists of several types of tissues, the main place of which is occupied by solid connective tissue - bone.

The outside of the bone is covered periosteum, except for articular surfaces covered with articular cartilage.

Bone contains red bone marrow, adipose tissue, blood vessels, lymphatic vessels and nerves.

The chemical composition of the bone. The bone consists of 1/3 organic (ossein, etc.) and 2/3 inorganic (calcium salts, especially phosphates) substances. Under the action of acids (hydrochloric, nitric, etc.), calcium salts dissolve, and the bone with the remaining organic substances will retain its shape, but become soft and elastic. If the bone is burned, then the organic substances will burn, and the inorganic ones will remain. The bone will also retain its shape, but it will become very brittle. It follows that the elasticity of the bone depends on ossein, and mineral salts give it hardness.

AT childhood bones contain more organic matter, so the bones in children are more flexible and rarely break. In older people, inorganic substances predominate in the chemical composition of the bones, the bones become less elastic and more brittle, so they break more often.

Classification of bones. According to the classification of M.G. Weight gain, bones are: tubular, spongy, flat and mixed.

tubular bones are long and short and perform the functions of support, protection and movement. Tubular bones have a body, a diaphysis, in the form of a bone tube, the cavity of which is filled in adults with yellow bone marrow. ends tubular bones called epiphyses. The cells of spongy tissue contain red bone marrow. Between the diaphysis and the epiphyses are the metaphyses, which are zones of bone growth in length.

spongy bones Distinguish between long (ribs and sternum) and short (vertebrae, carpal bones, tarsus).

They are built from a spongy substance covered with a thin layer of compact. Spongy bones include sesamoid bones (patella, pisiform bone, sesamoid bones of fingers and toes). They develop in the tendons of the muscles and are auxiliary devices for their work.

flat bones , forming the roof of the skull, built of two thin plates of compact substance, between which there is a spongy substance, diploe, containing cavities for veins; flat bones of the belts are built of spongy substance (scapula, pelvic bones). Flat bones perform the functions of support and protection,

mixed dice merge from several parts that have different functions, structure and development (bones of the base of the skull, collarbone).

Question 2. Types of bone joints.

All bone joints can be divided into 2 groups:

1) continuous connections - synarthrosis (fixed or inactive);

2) discontinuous connections - diarthrosis or joints (mobile in function).

The transitional form of bone joints from continuous to discontinuous is characterized by the presence of a small gap, but the absence of an articular capsule, as a result of which this form is called a semi-joint or symphysis.

Continuous connections - synarthroses.

There are 3 types of synarthrosis:

1) Syndesmosis - the connection of bones with the help of ligaments (ligaments, membranes, sutures). Example: skull bones.

2) Synchondrosis - connection of bones with the help of cartilaginous tissue (temporary and permanent). The cartilaginous tissue located between the bones acts as a buffer that softens shocks and tremors. Example: vertebrae, first rib and vertebra.

3) Synostosis - connection of bones through bone tissue. Example: pelvic bones.

Discontinuous connections, joints - diarthrosis. At least two are involved in the formation of joints. articular surfaces , between which is formed cavity , closed joint capsule . articular cartilage covering the articular surfaces of the bones, smooth and elastic, which reduces friction and softens shocks. Articular surfaces correspond or do not correspond to each other. The articular surface of one bone is convex and is the articular head, and the surface of the other bone, respectively, is concave, forming the articular cavity.

The articular capsule is attached to the bones that form the joint. Hermetically closes the articular cavity. It consists of two membranes: outer fibrous and inner synovial. The latter secretes a transparent liquid into the joint cavity - synovia, which moisturizes and lubricates the articular surfaces, reducing friction between them. In some joints, the synovial membrane forms, protruding into the joint cavity and containing significant amount fat.

Sometimes protrusions or eversion of the synovial membrane are formed - synovial bags lying near the joint, at the site of attachment of the tendons or muscles. Bursae contain synovial fluid and reduce friction between tendons and muscles during movement.

The articular cavity is a hermetically sealed slit-like space between the articular surfaces. Synovial fluid creates pressure in the joint below atmospheric pressure, which prevents the divergence of the articular surfaces. In addition, synovia is involved in the exchange of fluid and in strengthening the joint.

Question 3. The structure of the skeleton of the head, trunk and limbs.

The skeleton has the following parts:

1. axial skeleton

trunk skeleton (vertebrae, ribs, sternum)

The skeleton of the head (bones of the skull and face) form;

2. additional skeleton

girdles bones

Upper (scapula, clavicle)

Inferior (pelvic bone)

free limb bones

Upper (shoulder, bones of the forearm and hand)

Lower (thigh, bones of the lower leg and foot).

vertebral column is part of the axial skeleton, performs supporting, protective and locomotor functions: ligaments and muscles are attached to it, protects the spinal cord and participates in the movements of the trunk and skull. The spinal column has an S-shape due to the upright posture of a person.

The spinal column has the following divisions: cervical, consisting of 7, thoracic - of 12, lumbar - of 5, sacral - of 5 and coccygeal - of 1-5 vertebrae. The dimensions of the vertebral bodies gradually increase from top to bottom, reaching the largest sizes at the lumbar vertebrae; the sacral vertebrae are fused into a single bone, due to the fact that they bear the weight of the head, trunk and upper limbs.

The coccygeal vertebrae are a remnant of the tail that disappeared from humans.

Where the spine experiences the greatest functional load, the vertebrae and their individual parts are well developed. The coccygeal spine does not carry any functional load and therefore is a rudimentary formation.

The spinal column in the human skeleton is located vertically, but not straight, but forms bends in the sagittal plane. Curves in the neck and lumbar regions directed forward and are called lordosis , and in the thoracic and sacral - facing the bulge back - this kyphosis . The curves of the spine are formed after the birth of a child and become permanent by the age of 7-8 years.

With an increase in load, the bends of the spinal column increase, with a decrease in load, they become smaller.

The bends of the spinal column are shock absorbers during movements - they soften shocks along the spinal column, thus protecting the skull, and the brain located in it, from excessive concussions.

If the indicated bends of the spinal column in the sagittal plane are the norm, then the appearance of bends in the frontal plane (more often in the cervical and thoracic regions) is considered a pathology and is called scoliosis . The reasons for the formation of scoliosis can be different. So, schoolchildren can develop a pronounced lateral curvature of the spinal column - school scoliosis, as a result of improper fit or carrying a load (bag) in one hand. Scoliosis can develop not only in schoolchildren, but also in adults of certain professions associated with the curvature of the body during work. For the prevention of scoliosis, special gymnastics is necessary.

In old age, the spinal column becomes shorter due to a decrease in thickness. intervertebral discs, the vertebrae themselves and loss of elasticity. The spinal column bends anteriorly, forming one large thoracic bend (senile hump).

The spinal column is a rather mobile formation. Thanks to intervertebral discs and ligaments it is flexible and elastic. Cartilages push the vertebrae apart, and ligaments connect them to each other.

chest form 12 thoracic vertebrae, 12 pairs of ribs and sternum.

Sternum consists of three parts: handle, body and xiphoid process. A jugular notch is located on the upper edge of the handle.

There are 12 pairs of ribs in the human skeleton. With their posterior ends, they are connected to the bodies of the thoracic vertebrae. 7 upper pairs of ribs with their front ends are connected directly to the sternum and are called true ribs . The next three pairs (VIII, IX and X) join with their cartilaginous ends to the cartilage of the previous rib and are called false edges . XI and XII pairs of ribs are located freely in the abdominal muscles - this oscillating ribs .

Rib cage It has the shape of a truncated cone, the upper end of which is narrow, and the lower one is wider. Due to upright posture, the chest is somewhat compressed from front to back.

The lower ribs form the right and left costal arches. Under the xiphoid process of the sternum, the right and left costal arches converge, limiting the infrasternal angle, the value of which depends on the shape of the chest.

Shape and size chest depends on: age, gender, body type, degree of development of muscles and lungs, lifestyle and profession this person. AT chest located vitally important organs- heart, lungs, etc.

Distinguish 3 chest shape : flat, cylindrical and conical.

In people with well-developed muscles and lungs, brachymorphic body type, the chest becomes wide, but short and acquires conical shape. She is always in a state of inhalation. The infrasternal angle of such a chest will be obtuse.

In people of a dolichomorphic body type, with poorly developed muscles and lungs, the chest becomes narrow and long. This shape of the chest is called flat. Its front wall stands almost vertically, the ribs are strongly inclined. The chest is in a state of exhalation.

Do people have brachymorphic?? (meso) body type chest has cylindrical shape, occupying an intermediate position between the previous two. In women, the chest is shorter and narrower in the lower section than in men, and more rounded. In the process of growth and development, the shape of the chest is influenced by social factors.

Poor living conditions and malnutrition in children can significantly affect the shape of the chest. Children growing up with insufficient nutrition and solar radiation develop rickets (“English disease”), in which the chest takes the form of a “chicken breast”. The anteroposterior size predominates in it, and the sternum protrudes forward. In children with an incorrect posture when sitting, the chest is long and flat. The muscles are poorly developed. The chest is, as it were, in a collapsed state, which negatively affects the activity of the heart and lungs. For the proper development of the chest and the prevention of diseases in children, physical education, massage, proper nutrition, sufficient lighting and other conditions.

Scull (cranium) is a receptacle for the brain and associated sense organs; in addition, it surrounds the initial sections of the digestive and respiratory tracts. In this regard, the skull is divided into 2 parts: cerebral and facial. brain skull has a vault and a base.

Cerebral region of the skull in humans they form: unpaired - occipital, sphenoid, frontal and ethmoid bones and paired - temporal and parietal bones.

Facial region of the skull form paired - upper jaw, lower nasal concha, palatine, zygomatic, nasal, lacrimal and unpaired - vomer, lower jaw and hyoid.

The bones of the skull are connected to each other, mainly by sutures.

In the skull of a newborn, the cerebral region of the skull is relatively larger than the facial region. As a result, the facial skull protrudes slightly forward compared to the brain and makes up only an eighth of the latter, while in an adult this ratio is 1:4. Fontanelles are located between the bones that form the cranial vault. The fontanelles are the remains of a membranous skull, they are located at the intersection of the sutures. Fontanelles are of great functional importance. The bones of the cranial vault can go behind each other during childbirth, adapting to the shape and size of the birth canal.

The wedge-shaped and mastoid fontanelles overgrow either by the time of birth or immediately after birth. Newborns do not have stitches. Bones have smooth surfaces. Between the individual parts of the bones of the base of the skull that have not yet merged, there is cartilaginous tissue. Pneumatic sinuses in the bones of the skull are absent. The upper and lower jaws are poorly developed: the alveolar processes are almost absent, the lower ?? the jaw consists of two unfused halves. In adulthood, ossification of the sutures of the skull is observed.

Skeleton of the upper and lower limbs has a general structural plan and consists of two sections: belts and free upper and lower limbs. Through belts, free limbs are attached to the body.

Belt upper limb form two paired bones: the clavicle and the scapula.

Skeleton of the free upper limb consists of three sections: proximal - humerus; middle - two bones of the forearm - ulna and radius; and distal - bones of the hand.

The hand has three sections: the wrist, metacarpus and phalanges of the fingers.

Wrist form eight short spongy bones arranged in 2 rows. Each row consists of four bones.

metacarpus (metacarpus) is formed by five short tubular metacarpal bones

The bones of the fingers are the phalanges. Each finger has three phalanges located one behind the other. The exception is thumb having only two phalanges.

Everyone needs to know the human skeleton with the name of the bones. This is important not only for physicians, but also ordinary people, because information about his skeleton and muscles will help to strengthen him, feel healthy, and at some point they can help out in emergency situations.

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Types of bones in the adult body

The skeleton and muscles together make up the human locomotor system. The human skeleton is a whole complex of bones of different types and cartilage, interconnected with the help of continuous connections, synarthroses, symphyses. Bones are divided into:

• tubular, forming the upper (shoulder, forearm) and lower (thigh, lower leg) limbs;
• spongy, foot (in particular, tarsus) and human hand (wrists);
• mixed - vertebrae, sacrum;
• flat, this includes the pelvic and cranial bones.

Important! Bone tissue, despite its increased strength, is able to grow and recover. Metabolic processes take place in it, and blood is even formed in the red bone marrow. With age, bone tissue is rebuilt, it becomes able to adapt to various loads.

Types of bones

How many bones are in the human body?

The structure of the human skeleton undergoes many changes throughout life. On the initial stage development, the fetus consists of fragile cartilage tissue, which over time is gradually replaced by bone. A newborn baby has over 270 small bones. With age, some of them can grow together, for example, cranial and pelvic, as well as some vertebrae.

It is very difficult to say exactly how many bones in the body of an adult. Sometimes people have extra ribs or bones in the foot. There may be growths on the fingers, a slightly smaller or larger number of vertebrae in any of the spine. The structure of the human skeleton is purely individual. On average in an adult have from 200 to 208 bones.

Functions of the human skeleton

Each department performs its highly specialized tasks, but the human skeleton as a whole has several common functions:

1. Support. The axial skeleton is a support for all soft tissues of the body and a system of levers for the muscles.
2. Motor. Movable joints between bones allow a person to make millions of precise movements with the help of muscles, tendons, ligaments.
3. Protective. The axial skeleton protects the brain and internal organs from injury, acts as a shock absorber during impacts.
4. Metabolic. Bone tissue contains a large number of phosphorus, and iron, involved in the exchange of minerals.
5. Hematopoietic. The red marrow of tubular bones is the place where hematopoiesis takes place - the formation of erythrocytes (red blood cells) and leukocytes (cells of the immune system).

If some skeletal functions are impaired, diseases may occur. varying degrees gravity.

Functions of the human skeleton

Departments of the skeleton

The human skeleton is divided into two large sections: axial (central) and additional (or limb skeleton). Each department performs its own tasks. The axial skeleton protects the abdominal organs from damage. The skeleton of the upper limb connects the arm to the torso. Due to the increased mobility of the bones of the hand, it helps to perform many precise finger movements. The functions of the skeleton of the lower extremities are to bind the legs to the body, move the body, and cushion when walking.

Axial skeleton. This department forms the basis of the body. It includes: the skeleton of the head and torso.

Head skeleton. The cranial bones are flat, immovably connected (with the exception of the movable mandible). They protect the brain and sense organs (hearing, sight and smell) from concussions. The skull is divided into the facial (visceral), cerebral and middle ear sections.

Torso skeleton. The bones of the chest. In appearance, this subsection resembles a compressed truncated cone or pyramid. The chest includes paired ribs (out of 12, only 7 are articulated with the sternum), the vertebrae of the thoracic spine and the sternum - an unpaired sternum.

Depending on the connection of the ribs with the sternum, true (upper 7 pairs), false (next 3 pairs), floating (last 2 pairs) are distinguished. The sternum itself is considered the central bone included in the axial skeleton.

The body is isolated in it, upper part- handle, and lower part- xiphoid process. The bones of the chest are connection of increased strength with the vertebrae. Each vertebra has a special articular fossa designed for attachment to the ribs. This method of articulation is necessary to perform the main function of the skeleton of the body - the protection of human life support organs:, lungs, parts of the digestive system.

Important! The bones of the chest are subject to external influences, prone to modification. Physical activity and proper seating at the table contribute to proper development chest. A sedentary lifestyle and stoop lead to tightness of the chest organs and scoliosis. An improperly developed skeleton threatens with serious health problems.

Spine. The department is central axis and main support Total human skeleton. The spinal column is formed from 32-34 individual vertebrae that protect the spinal canal with nerves. The first 7 vertebrae are called cervical, the next 12 are thoracic, then come the lumbar (5), 5 fused, forming the sacrum, and the last 2-5, constituting the coccyx.

The spine supports the back and trunk, provides due to the spinal nerves motor activity the whole body and the connection of the lower body with the brain. The vertebrae are connected to each other semi-mobile (in addition to the sacral). This connection is carried out through the intervertebral discs. These cartilaginous formations soften shocks and tremors during any movement of a person and provide flexibility to the spine.

limb skeleton

Skeleton of the upper limb. Skeleton of the upper limb represented by the shoulder girdle and the skeleton of the free limb. The shoulder girdle connects the arm to the body and includes two paired bones:

1. The clavicle, which has an S-shaped bend. At one end it is attached to the sternum, and at the other it is connected to the scapula.
2. Shoulder blade. In appearance, it is a triangle adjacent to the back of the body.

The skeleton of the free limb (hand) is more mobile, since the bones in it are connected large joints(shoulder, wrist, elbow). Skeleton represented by three subdivisions:

1. Shoulder, which consists of one long tubular bone - the humerus. One of its ends (epiphyses) is attached to the scapula, and the other, passing into the condyle, to the forearms.
2. Forearm: (two bones) the ulna, located on the same line with the little finger and the radius - in line with the first finger. Both bones on the lower epiphyses form a wrist joint with the carpal bones.
3. A brush that includes three parts: the bones of the wrist, metacarpus and finger phalanges. The wrist is represented by two rows of four spongy bones in everyone. The first row (pisiform, trihedral, lunate, navicular) serves to attach to the forearm. In the second row are the hamate, trapezium, capitate and trapezoid bones facing the palm. The metacarpus consists of five tubular bones, with their proximal part they are motionlessly connected to the wrist. Finger bones. Each finger has three phalanges connected to each other, in addition to the thumb, which is opposed to the rest, and has only two phalanges.

Skeleton lower limb. The skeleton of the leg, as well as the hand, consists of a limb belt and its free part.

limb skeleton

The belt of the lower extremities is formed by paired pelvic bones. They grow together from paired pubic, iliac and ischial bones. This happens by the age of 15-17, when the cartilaginous connection is replaced by a fixed bone one. Such strong articulation is necessary for the maintenance of the organs. Three bones to the left and right of the axis of the body form along the acetabulum, which is necessary for the articulation of the pelvis with the head of the femur.

The bones of the free lower limb are divided into:

• Femoral. The proximal (upper) epiphysis connects to the pelvis, and the distal (lower) to the tibia.
• The patella (or patella) covers, formed at the junction of the femur and tibia.
• The lower leg is represented by the tibia, located closer to the pelvis, and the fibula.
• Foot bones. The tarsus is represented by seven bones that make up 2 rows. One of the largest and well developed is calcaneus. The metatarsus is the middle part of the foot, the number of bones included in it is equal to the number of fingers. They are connected to the phalanges by means of joints. Fingers. Each finger consists of 3 phalanges, except for the first, which has two.

Important! During life, the foot is subject to modifications, calluses and growths can form on it, and there is a risk of developing flat feet. Often this is due to the wrong choice of shoes.

Sex differences

The structure of a woman and a man has no major differences. Only separate parts of some bones or their sizes are subject to changes. Among the most obvious, a narrower chest and a wide pelvis in a woman are distinguished, which is associated with labor activity. The bones of men, as a rule, are longer, more powerful than women's, and have more traces of muscle attachment. Distinguishing a female skull from a male is much more difficult. The skull of men is slightly thicker than the female, it has a more pronounced contour of the superciliary arches and the occipital protuberance.

The area of ​​the bone where the diaphysis passes into the epiphysis is isolated as metaphysis. According to the external shape, the bones are long, short, flat and mixed. Bones, which have a significant volume and experience stress in many directions, consist mainly of spongy substance. Bone has a complex structure and chemical composition. For example, the vertebral body in shape (and structure) refers to spongy bones, the arc, processes - to flat ones.

Therefore, it is more correct to distinguish bones on the basis of 3 principles on which any anatomical classification should be built: forms (structures), functions and development. I. Tubular bones. They are built from a spongy and compact substance that forms a tube with a bone marrow cavity; perform all 3 functions of the skeleton (support, protection and movement).

See what "Flat bones" are in other dictionaries:

IV. Mixed bones (bones of the base of the skull). The clavicle, which develops partly endosmally, partly endochondral, can also be attributed to mixed bones. Each epiphysis has an articular surface, facies articuldris, covered with articular cartilage, which serves to connect with neighboring bones.

X-ray anatomy of bones

This area corresponds to the epiphyseal cartilage ossified in postnatal ontogenesis. Tubular bones make up the skeleton of the limbs, act as levers. There are long bones (humerus, femur, bones of the forearm and lower leg) and short bones (metacarpal, metatarsal, phalanges of the fingers). Short (spongy) bone, os breve, has the shape of an irregular cube or polyhedron.

Flat (wide) bones, ossa plana, are involved in the formation of body cavities and also perform the function of protection (bones of the skull roof, pelvic bones, sternum, ribs). Abnormal (mixed) bones, ossa irregularia, are complexly built, their shape is varied. These include some bones of the skull: frontal, sphenoid, ethmoid, upper jaw. There are irregularities on the surfaces of each bone: muscles and their tendons, fascia, ligaments begin or attach here.

In places where a vessel or nerve passes through a bone, a canal, canalis, Canadian, canaliculus, gap, fissura, notch, inclsura are formed. On the surface of each bone, especially on its inner side, pinpoint holes are visible that go deep into the bone - nutrient holes, foramina nutricia. The rounded epiphysis, delimited from the body of the bone by a narrowing neck, collum, is called the head (cdput-head, capitulum-head).

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The predominance of organic substances in the bone (in children) provides it with greater elasticity and elasticity. When the ratio changes in the direction of the predominance of inorganic substances, the bone becomes brittle, fragile (in the elderly). The outer layer of the compact substance of the bone is formed by the outer surrounding plates. The inner layer of the bone, which limits the medullary cavity and is covered by the endosteum, is represented by the inner surrounding plates.

Nerve fibers and blood vessels branch out in the bone marrow. In the medullary cavity of the diaphyses of tubular bones there is a yellow bone marrow, medulla ossium fidva, which is a degenerate reticular stroma with fatty inclusions. Compact bone substance, consisting of concentrically arranged bone plates, is well developed in bones that perform the function of support and the role of levers (tubular bones).

The compact substance of the spongy (short) and epiphyses of the tubular bones on radiographs is represented by a narrow light stripe. The features of the structure of bones in accordance with professional affiliation are noted. Sesamoid bones are located near the joints, participating in their formation and facilitating movements in them, but they are not directly connected with the bones of the skeleton.

tubular bones are long and short and perform the functions of support, protection and movement. Tubular bones have a body, a diaphysis, in the form of a bone tube, the cavity of which is filled in adults with yellow bone marrow. The ends of tubular bones are called epiphyses. The cells of spongy tissue contain red bone marrow. Between the diaphysis and the epiphyses are the metaphyses, which are zones of bone growth in length.

spongy bones Distinguish between long (ribs and sternum) and short (vertebrae, carpal bones, tarsus).

They are built from a spongy substance covered with a thin layer of compact. Spongy bones include sesamoid bones (patella, pisiform bone, sesamoid bones of fingers and toes). They develop in the tendons of the muscles and are auxiliary devices for their work.

flat bones , forming the roof of the skull, built of two thin plates of compact substance, between which there is a spongy substance, diploe, containing cavities for veins; flat bones of the belts are built of spongy substance (scapula, pelvic bones). Flat bones perform the functions of support and protection,

mixed dice merge from several parts that have different functions, structure and development (bones of the base of the skull, collarbone).

Question 2. Types of bone joints.

All bone joints can be divided into 2 groups:

continuous connections - synarthrosis (fixed or inactive);

discontinuous connections - diarthrosis or joints (mobile in function).

The transitional form of bone joints from continuous to discontinuous is characterized by the presence of a small gap, but the absence of an articular capsule, as a result of which this form is called a semi-joint or symphysis.

Continuous connections - synarthroses.

There are 3 types of synarthrosis:

Syndesmosis is the connection of bones with the help of ligaments (ligaments, membranes, sutures). Example: skull bones.

Synchondrosis - connection of bones with the help of cartilaginous tissue (temporary and permanent). The cartilaginous tissue located between the bones acts as a buffer that softens shocks and tremors. Example: vertebrae, first rib and vertebra.

Synostosis is the connection of bones through bone tissue. Example: pelvic bones.

Discontinuous connections, joints - diarthrosis . At least two are involved in the formation of joints. articular surfaces , between which is formed cavity , closed joint capsule . articular cartilage covering articular surfaces of bones, smooth and elastic, which reduces friction and softens shocks. Articular surfaces correspond or do not correspond to each other. The articular surface of one bone is convex and is the articular head, and the surface of the other bone, respectively, is concave, forming the articular cavity.

The articular capsule is attached to the bones that form the joint. Hermetically closes the articular cavity. It consists of two membranes: outer fibrous and inner synovial. The latter secretes a transparent liquid into the joint cavity - synovia, which moisturizes and lubricates the articular surfaces, reducing friction between them. In some joints, the synovial membrane forms, protruding into the joint cavity and containing a significant amount of fat.

Sometimes protrusions or eversion of the synovial membrane are formed - synovial bags lying near the joint, at the site of attachment of the tendons or muscles. Bursae contain synovial fluid and reduce friction between tendons and muscles during movement.

The articular cavity is a hermetically sealed slit-like space between the articular surfaces. Synovial fluid creates pressure in the joint below atmospheric pressure, which prevents the divergence of the articular surfaces. In addition, synovia is involved in the exchange of fluid and in strengthening the joint.

Main part musculoskeletal system human - a skeleton consisting of more than two hundred different bones. It enables people to move, supports internal organs. In addition, they are the focus minerals, as well as the shell that contains the bone marrow.

Skeleton Functions

The various types of bones that make up the human skeleton primarily act as a means of supporting and supporting the body. Some of them serve as a receptacle for certain internal organs, such as the brain, located in the bones of the skull, lungs and heart, located in the chest, and others.

We also owe the ability to make various movements and move around to our own skeleton. In addition, human bones contain up to 99% of the calcium found in the body. Red bone marrow is of great importance in human life. It is located in the skull, spine, sternum, collarbone and some other bones. Bone marrow produces blood cells: erythrocytes, platelets and leukocytes.

The structure of the bone

The anatomy of a bone has extraordinary properties that determine its strength. The skeleton must withstand a load of 60-70 kg - this is the average weight of a person. In addition, the bones of the trunk and limbs work as levers that allow us to move and perform various activities. This is achieved due to their amazing composition.

Bones consist of organic (up to 35%) and inorganic (up to 65%) substances. The former include protein, mainly collagen, which determines the firmness and elasticity of tissues. Inorganic substances - calcium and phosphorus salts - are responsible for hardness. The combination of these elements gives the bones a special strength, comparable, for example, with cast iron. They can be perfectly preserved for many years, as evidenced by the results of various excavations. can disappear as a result of calcination of tissues, as well as when they are exposed to sulfuric acid. Minerals are very resistant to external influences.

Human bones are permeated with special tubules through which blood vessels pass. In their structure, it is customary to distinguish between compact and spongy substances. Their ratio is determined by the location of the bone in the human body, as well as the functions it performs. In areas where resistance to heavy loads, the main one is a dense compact substance. Such a bone consists of many cylindrical plates placed one inside the other. spongy substance appearance resembles a honeycomb. In its cavities is red bone marrow, and in adults it is also yellow, in which fat cells are concentrated. The bone is covered by a special connective tissue sheath - the periosteum. It is permeated with nerves and blood vessels.

Bone classification

Exist various classifications, which cover all types of bones of the human skeleton, depending on their location, structure and functions.

1. By location:

• cranial bones;
• body bones;
• limb bones.

2. By development they distinguish the following types bones:

• primary (appear from connective tissue);
• secondary (formed from cartilage);
• mixed.

3. The following types of human bones are distinguished by structure:

• tubular;
• spongy;
• flat;
• mixed.

Thus, science knows different kinds bones. The table makes it possible to more clearly present this classification.

tubular bones

Tubular long bones composed of both dense and spongy matter. They can be divided into several parts. The middle of the bone is formed by a compact substance and has an elongated tubular shape. This area is called the diaphysis. Its cavities first contain red bone marrow, which is gradually replaced by yellow, containing fat cells.

At the ends of the tubular bone is the epiphysis - this is the area formed by the spongy substance. Red bone marrow is placed inside it. The area between the diaphysis and the epiphysis is called the metaphysis.

During the period of active growth of children and adolescents, it contains cartilage, due to which the bone grows. Over time, the anatomy of the bone changes, the metaphysis completely turns into bone tissue. The long ones include the thigh, shoulder, bones of the forearm. Tubular small bones have a slightly different structure. They have only one true epiphysis and, accordingly, one metaphysis. These bones include the phalanges of the fingers, the bones of the metatarsus. They function as short levers of movement.

Spongy types of bones. Pictures

The name of the bones often indicates their structure. For example, spongy bones are formed from a spongy substance covered with a thin layer of compact. They do not have developed cavities, so the red bone marrow is placed in small cells. Spongy bones are also long and short. The former include, for example, the sternum and ribs. Short spongy bones are involved in the work of muscles and are a kind of auxiliary mechanism. These include vertebrae.

flat bones

These types of human bones, depending on their location, have different structure and perform certain functions. The bones of the skull are primarily protection for the brain. They are formed by two thin plates of dense substance, between which is located spongy. It has openings for veins. The flat bones of the skull develop from connective tissue. The scapula and also belong to the type of flat bones. They are formed almost entirely from a spongy substance that develops from cartilage tissue. These types of bones perform the function of not only protection, but also support.

mixed dice

Mixed bones are a combination of flat and short spongy or tubular bones. They develop different ways and perform those functions that are necessary in a particular part of the human skeleton. Types of bones such as mixed bones are found in the body temporal bone, vertebrae. These include, for example, the clavicle.

cartilage tissue

Cartilage has an elastic structure. She shapes auricles, nose, some parts of the ribs. It is also located between the vertebrae, as it perfectly resists the deforming force of loads. It has high strength, excellent resistance to abrasion and crushing.

Connection of bones

There are different ones that determine the degree of their mobility. The bones of the skull, for example, have a thin layer of connective tissue. However, they are absolutely immobile. Such a connection is called fibrous. Between the vertebrae are also areas of connective or cartilaginous tissue. Such a connection is called semi-movable, since the bones, although limited, can move a little.

Joints that form synovial joints have the highest mobility. The bones in the joint bag are held by ligaments. These fabrics are both flexible and durable. In order to reduce friction, a special oily fluid is located in the joint - synovia. It envelops the ends of the bones, covered with cartilage, and facilitates their movement.

There are several types of joints. As the name of the bones is determined by their structure, so the name of the joints depends on the shape of the bones that they connect. Each type allows you to perform certain movements:

• Ball joint. With this connection, the bones move in many directions at once. These joints include the shoulder and hip joints.
• Block joint (elbow, knee). Assumes movement exclusively in one plane.
• Cylindrical joint allows the bones to move relative to each other.
• Flat joint. It is inactive, provides movements of a small scope between two bones.
• Ellipsoidal joint. Thus, for example, the radius is connected to the bones of the wrist. They can move from side to side within the same plane.
• Thanks to saddle joint the thumb can move in different planes.

The impact of physical activity

Degree physical activity has a significant effect on the shape and structure of bones. At different people the same bone can have its own characteristics. With constant impressive physical exertion, the compact substance thickens, and the cavity, on the contrary, shrinks in size.

Negatively affects the condition of the bones long stay in bed, sedentary lifestyle. Fabrics become thinner, lose their strength and elasticity, become brittle.

Changes under the influence of physical activity and the shape of the bones. Those places where muscles act on them can become flatter. With particularly intense pressure, small depressions may even occur over time. In areas of strong stretching, where ligaments act on the bones, thickenings, various irregularities, and tubercles can form. Especially such changes are typical for people professionally involved in sports.

A variety of injuries, especially those received in adulthood, also affect the shape of the bones. When the fracture grows together, all kinds of deformations can occur, which often adversely affect the effective management of one's body.

Age-related changes in bones

In different periods of a person's life, the structure of his bones is not the same. In infants, almost all bones consist of a spongy substance, which is covered with a thin layer of compact. Their continuous, up to a certain time, growth is achieved due to an increase in the size of cartilage, which is gradually replaced by bone tissue. This transformation continues until the age of 20 in women and up to about 25 in men.

How younger man, the more organic matter is contained in the tissues of its bones. Therefore, in early age they are elastic and flexible. In an adult, the volume of mineral compounds in bone tissue is up to 70%. At the same time, from a certain point, a decrease in the amount of calcium and phosphorus salts begins. Bones become brittle, so older people often experience fractures even as a result of a minor injury or a careless sudden movement.

These fractures take a long time to heal. There is a special disease characteristic of the elderly, especially women - osteoporosis. For its prevention, upon reaching the age of 50, it is necessary to consult a doctor for some research to assess the condition of the bone tissue. With appropriate treatment, the risk of fractures is significantly reduced and the healing time is shortened.