Skeleton of Man

    Abstract

 

         On the topic of "Skeleton Man"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                                                                                                     Prepared: Zhomartova Alina

 

 

 

Content

 

1. Structure and function of the skeleton 3

2. The structure and shape of the bones 6

3. Spine 7

4. Chest 14

5. The sternum and ribs 15

6. The skeleton of the upper extremity 16

7. The skeleton of the lower extremity 17

8. The skeleton of the head 18

9. Features of the structure of the skull 19 newborn

10. List of sources 20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 Structure and function of skeletal

Passive part of the musculoskeletal system is a complex human bones and their joints - a skeleton. The skeleton consists of bones of the skull, spine and rib cage (the so-called axial skeleton), and the bones of the upper and lower limbs (extension skeleton).

The skeleton is characterized by high strength and flexibility, which provides a way to connect bones to each other.

Moving the connection of most bones skeleton gives the necessary flexibility and ensures freedom of movement. In addition to the continuous fibrous and cartilaginous joints (they are mainly connected with each other bones of the skull) in the skeleton, there are several types of less severe bone joints. Each type of connection depends on the desired degree of mobility and the type of loads at the site of the skeleton. Compounds with limited mobility or polusustavami called symphysis, and discontinuous (synovial) compounds - joints. The complex geometry of the articular surfaces exactly corresponds to the degree of freedom of the compound.

The bones of the skeleton are involved in the process of hematopoiesis and mineral metabolism, and bone marrow is an important part of the body's immune system. In addition, the components of the skeleton bones serve as a support for the organs and soft tissues of the body, protects vital internal organs.

Human skeleton continues its development throughout life bone is constantly being updated and grow, responding to the growth of the whole organism, the individual bones (eg, sacral, or coccygeal) that children are separated, as they grow older fused into one bone. By the time of birth of the bones of the skeleton has not yet been formed and many of them are composed of cartilage (Fig. 2).

 

 

    

 

In Fig. A. Human skeleton

A - front view, B - rear view:

1 - skull;

2 - the chest;

3 - the bones of the upper extremity;

4 - the spinal column;

5 - pelvic bone;

6 - the bones of the lower extremities.

The skull of the fetus at the age of 9 months is not a rigid structure, the individual components of his bones are not fused, which should provide a relatively easy passage through the birth canal. Other features: not fully developed zone of the upper extremities of bone (scapula and clavicle), the majority of the tarsal bones of the wrist and even cartilage, at the time of birth is not well formed and the bones of the chest (in the newborn xiphoid cartilage and the sternum is represented by separate, not fused between a bony points). The vertebrae in this age group are divided relatively thick intervertebral disks and vertebrae themselves are just beginning to take shape: the body and vertebral arch is not fused and presented with bone points. Finally, the pelvic bone at this point consists only of the rudiments of the ischial bone, the pubic and iliac bones.

The skeleton of an adult consists of more than 200 bones, and his weight (on average) in men is about 10 kg, females about 7 kg. The internal structure of each of the bones optimally adapted to the bone to successfully carry out all the many functions that are assigned to it by nature. Involvement of bones that make up the skeleton in metabolism is provided by blood vessels which penetrate every bone. The nerve endings that penetrate into the bone, let her, as well as throughout the skeleton as a whole to grow and evolve, to adequately respond to changes in living environment and external conditions of existence of the body.

Structural unit of the reference unit, which forms the bones of the skeleton, as well as cartilage, ligaments, tendons and fascia is the connective tissue. A common characteristic of the different structure of the connective tissue is that they are composed of cells and intercellular substance, which consists of fibrous structures and amorphous material. Connective tissue performs various functions: as a part of the food web - the formation of the stroma, the power cells and tissues, transport of oxygen, carbon dioxide, as well as mechanical, protective, that is, combines different types of tissues and protects organs from damage, viruses and microorganisms.

 

In Fig. Two. The skeleton of the fetus:

 

1 - skull;

2 - the bones of the upper extremity;

3 - the chest;

4 - the spinal column;

5 - pelvic bone;

6 - the bones of the lower extremity

The connective tissue is divided into proper connective tissue and connective tissue with special reference (bone and cartilage) and hematopoietic (myeloid and lymphatic tissue) properties.

Actually the connective tissue is subdivided into fibrous and connective tissue with special properties, which include reticular, pigment, fat and mucous tissue. Fibrous tissue is represented unformed loose connective tissue accompanying the blood vessels, ducts, nerves, organs separating from each other and from the cavities of the body, thus forming the stroma of organs, and also decorated dense and loose connective tissue that forms ligaments, tendons, aponeuroses, fascia, perinevrii, fibrous membrane and elastic tissue.

Bone tissue forms the bone skeleton of the head and limbs, axial skeleton body, protects organs, located in the skull, chest and pelvic cavities, is involved in mineral metabolism. In addition, bone tissue determines the shape of the body. It consists of cells, which are the osteocytes, osteoblasts and osteoclasts, and of the intercellular substance containing collagen fibers of bone and bone ground substance, which are deposited minerals that make up 70% of the total bone mass. Thanks to so many basic salts of bone substance is characterized by high strength.

Bone tissue is divided into coarse-fibered, or retikulofibroznuyu characteristic of embryos and young organisms, and lamellar tissue component of the bones of the skeleton, which, in turn, is divided into sponge contained in the epiphysis of bones, and a compact, located in the diaphysis of long bones.

Cartilage cells, chondrocytes and formed intercellular substance of high density. Cartilage perform a support function and are included in various parts of the skeleton. There are fibrous cartilage that is part of the intervertebral discs and joints pubic bone, hyaline, cartilage forming the articular surfaces of bones, the ends of the ribs, trachea, bronchi, and elastic, which forms the epiglottis and ears.

2 Structure and shape of the bones

The combination of the required mechanical properties of bone - both flexibility and mechanical strength - its composition is provided. Bone 2/3 is composed of an inorganic material (calcium) and the third - of the organic matter (ossein protein). Calcium salts give bone hardness, and ossein provides significant flexibility.

The structure of isolated bone periosteum (periosteum), a compact substance, spongy substance, and bone marrow.

The periosteum covers the entire outer surface of bone except joint. It runs through a lot of fine blood vessels and nerve fibers in bone tubules penetrating into the bone, due to what is provided by its blood supply and innervation. In structure the periosteum is a thin plate of connective tissue, its outer layer is composed of dense fibrous fibers, and internal - of fibrous and loose connective tissue in which lie osteoblasts - osteoplastic cells. The inner layer is called the cambial periosteum, he is responsible for bone growth in thickness; osteoblasts cambial layer also provide recovery of bone after fracture.

The compact substance consisting of bony plates covered by a dense layer of the periphery of the bone. Part of the bony plates that make up the compact substance, forms a structural unit of the actual bone - osteon.

Osteon - a cylindrical formation consisting of several layers of bony plates of cylindrical form, as it were inserted into each other and surrounding the central channel, which are the nerves and blood vessels. The intervals between osteons is occupied intercalary plate; inside and outside osteons and intercalary plates are covered with the surrounding plates. Osteons are arranged in accordance with the loads acting on this bone.

Cancellous bone, which is located under the compact, different porous structure. It is formed bone beams (trabeculae) which, in turn, are composed of bony plates, oriented in the direction of current loads on the bone.

Bone marrow provides bone as an organ functioning. There are yellow and red bone marrow.

Yellow bone marrow is located in the medullary cavity and consists mainly of fat cells (they determine the color).

Red bone marrow is located in cancellous bone - Body bone formation and hematopoiesis. It consists of a reticulum and densely penetrated by blood vessels. For these vessels the blood cells, which mature in hematopoietic cells (stem cells), bone marrow, enter the bloodstream of the body. In the hinges of the reticular tissue, in addition to stem cells, are also the cells that make and destroy bone - osteoblasts and osteoclasts.

The shape of the diversity of bone is divided into four groups: isolated tubular sponge, flat, and mixed bone. Different roles of these bones in the skeleton determines the differences in their internal structure.

The tubular bones are distinguished by a more or less elongated cylindrical central part - of the diaphysis, or bones of the body. Diaphysis consists of a compact material that surrounds the inner medullary cavity containing yellow marrow. Distinguish long and short tubular bones: the long bones are the bones of the shoulder, forearm, thigh and lower leg, and to short - phalanges, and metatarsal bones and the metacarpus. Diaphysis of long bones from both sides ends pineal gland, which is filled with spongy material containing red marrow. Between the epiphysis and diaphysis is the metaphysis are separated.

Spongy bone, consisting of a spongy substance, is also divided into long and short. For a long spongy bones are the bones of the chest - ribs and sternum, and a short - vertebrae, carpal bones, tarsal, and sesamoid bones (located in the tendons of the muscles near the joints). From the spongy bones differ in the absence of the medullary cavity, spongy bone on the outside covered with a thin layer of compact substance.

By the flat bones include the bones of the scapula, pelvic bones, the bones of the skull cap. Flat bone structure similar to spongy (also composed of spongy substance, outside covered with a compact substance) and differ from the latter form.

In addition to these, the skeleton is also made mixed bone, which consist of parts, different in function, form and origin. Mixed bones found among the bones of the skull base.

3 Spine

The spinal column (Fig. 3, 4) - the real basis of the skeleton, bearing the entire body. The design of the spine allows it, while maintaining the flexibility and mobility, maintain the same load, which can withstand up to 18 times thicker concrete pole.

The spinal column is responsible for maintaining posture, serves as a support for tissues and organs, as well as take part in forming the walls of the chest, pelvis and abdomen. Each of the vertebrae that make up the spinal column is inside the through-hole vertebrate (Fig. 8). In the spine vertebral opening up the spinal canal (Fig. 3), which contains the spinal cord, which is thus protected from external influences.

In the frontal projection of spine clearly highlighted two areas of differing broader vertebrae. In general, weight and dimensions of the vertebrae grow in the direction from top to bottom: it is necessary to compensate for the increasing burden carried by the lower vertebrae.

In addition to thickening of the vertebrae, the necessary degree of strength and elasticity of the spine to provide a few twists that lie in the sagittal plane. Four different directions of bending, alternating the spine, are located in pairs, bending, forward-facing (lordosis), corresponds to the bend, facing back (kyphosis). Thus, the cervical and lumbar lordosis and sacral rib meet kyphosis (Fig. 3). With this design the spine works like a spring, distributing the load evenly over its entire length.

 

 

In Fig. Three. The spinal column (right side):

 

1 - cervical lordosis;

2 - thoracic kyphosis;

3 - lumbar lordosis;

4 - sacral kyphosis;

5 - protruding vertebrae;

6 - the spinal canal;

7 - spinous processes;

8 - the vertebral body;

9 - the intervertebral foramen;

10 - sacral canal

 

In Fig. 4. The spine (front view):

 

1 - cervical vertebrae;

2 - thoracic vertebrae;

3 - lumbar vertebrae;

4 - sacral vertebrae;

5 - atlas;

6 - transverse processes;

7 - coccyx

A total of 32-34 spine vertebrae separated by intervertebral disks and their slightly different device.

The structure of a single vertebra is isolated vertebral body and vertebral arch, which closes the vertebral opening. On the arc of the vertebral processes are of different shape and purpose: paired upper and lower articular processes, transverse, and a pair of spinous process, the speaker of the vertebral arch backward. The base of the arc is the so-called vertebral notch - top and bottom. Intervertebral foramen, formed by two adjacent vertebrae clippings, provide access to the vertebral canal on the left and right (Fig. 3, 5, 7, 8, 9).

In accordance with the location and structural features in the spinal column distinguishes five types of vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 3-5 coccygeal (Fig. 4).

Cervical vertebra differs from others in that it has a hole in the transverse processes. Vertebrate hole formed by the arc of the cervical vertebra, a large, almost triangular in shape. The body of the cervical vertebrae (except I cervical vertebra, which has no body) is relatively small, oval and elongated in the transverse direction.

I have cervical vertebra, or atlas (Fig. 5), the body is absent, and its lateral masses connected by two arches - front and back. The upper and lower planes of the lateral masses have articular surfaces (top and bottom), by which I connected to the thoracic vertebrae, respectively, with a skull and II cervical vertebra.

 

In Fig. Five. I cervical vertebra (atlas)

 

A - top view, B - view from below:

1 - back arc;

2 - vertebral foramen;

3 - transverse process;

4 - the opening of the transverse process;

5 - costal process;

6 - lateral mass;

7 - superior articular pit of atlas;

8 - hole of the tooth;

9 - anterior arch;

10 - lower articular fossa

In turn, II cervical vertebra (Fig. 6) characterized by the presence of a massive body in the process, the so-called tooth, which is the origin of the body I cervical vertebra. Tooth II cervical vertebra - the axis around which revolves the head with the atlas, so II cervical vertebra is called the axis.

 

 

   

 

In Fig. 6. II cervical vertebra

 

A - front view, B - left side:

1 - dens of the axis;

2 - superior articular process;

3 - transverse process;

4 - the lower articular process;

5 - the vertebral body;

6 - an arc of a vertebra;

7 - spinous process;

8 - the opening of the transverse process

 

 

 

In Fig. 7. VI cervical vertebra (top view):

 

1 - spinous process;

2 - vertebral foramen;

3 - inferior articular process;

4 - superior articular process;

5 - the vertebral body;

6 - transverse process;

7 - the opening of the transverse process;

8 - costal process

In the transverse processes of cervical vertebrae can be found rudimentary edge processes, which are particularly well developed in the VI cervical vertebra. VI cervical vertebra is also acting as its spinous process much longer than that of the adjacent vertebrae.

Thoracic vertebra (Fig. 8) features a large, in comparison with cervical, body, and almost round hole vertebrates. Thoracic vertebrae have a transverse process at its costal pit, which serves to connect to the rib hump. On the lateral surfaces of the body is the thoracic vertebra and the upper and lower rib-pits, which include the head of the rib.

 

 

   

 

In Fig. Eight. VIII thoracic vertebra

 

A - right side view, B - view from above:

1 - superior articular process;

2 - the upper vertebral notch;

3 - upper rib fossa;

4 - transverse process;

5 - costal pit of transverse process;

6 - the vertebral body;

7 - spinous process;

8 - the lower articular process;

9 - inferior vertebral notch;

10 - the lower costal fossa;

11 - an arc of a vertebra;

12 - hole vertebrate

 

 

 

In Fig. 9. III lumbar vertebrae (top view):

 

1 - spinous process;

2 - superior articular process;

3 - inferior articular process;

4 - transverse process;

5 - vertebral foramen;

6 - the vertebral body

Lumbar vertebrae (Fig. 9) differ horizontally directed spinous processes with small gaps between them, as well as a massive bean-shaped body. Compared with the vertebrae of the cervical and thoracic lumbar vertebra has a relatively small vertebrate hole oval.

Sacral vertebrae are separated before the age of 18-25 years, after which they fuse with each other, forming a single bone - the sacrum (Fig. 10). The sacrum is triangular in shape, facing the top down, it is isolated base (Fig. 10), top (Fig. 10) and lateral parts, as well as the anterior and posterior pelvic surface. Inside the sacrum is sacral canal (Fig. 10). The reason the sacrum articulates with the V lumbar vertebrae, and the apex of the coccyx.

 

   

 

In Fig. 10. Sacrum

 

A - front view, B - rear view:

1 - the base of the sacrum;

2 - the superior articular process I sacral vertebra;

3 - anterior sacral foramen;

4 - cross the line;

5 - top of the sacrum;

6 - sacral canal;

7 - posterior sacral foramen;

8 - the median sacral crest;

9 - the right ear-shaped surface;

10 - Intermediate sacral crest;

11 - lateral sacral crest;

12 - sacral hiatus;

13 - sacral horns

The lateral part of the sacrum are formed by the transverse processes fused ribs, and rudiments of the sacral vertebrae. The upper parts of the lateral surface of the lateral parts of the ear-shaped articular surface are (Fig. 10), whereby the sacrum articulates with the pelvic bones.

 

In Fig. 11. Coccyx

 

A - front view, B - rear view:

1 - coccygeal horn;

2 - outgrowths of the body I coccygeal vertebra;

3 - coccygeal

Front pelvic surface of sacrum is concave, with prominent signs of fusion of vertebrae (transverse lines are of the form) forms the rear wall of the pelvic cavity.

Four lines that mark the place seam sacral vertebrae, ends on both sides of the anterior sacral foramina (Fig. 10).

The back (dorsal) surface of the sacrum, and has four pairs of posterior sacral foramina (Fig. 10), rough and convex, with passing the center of the vertical comb. This is the median sacral crest (Fig. 10) is followed by fusion of the spinous processes of the sacral vertebrae. On the left and right of it are intermediate sacral crests (Fig. 10) formed by fusion of the articular processes of the sacral vertebrae. Fused transverse processes of sacral vertebrae form the paired lateral sacral crest.

Paired intermediate sacral crest ends at the top of the usual superior articular process I sacral vertebra, and below - modified the lower articular processes V sacral vertebra. These processes, called sacral horns (Fig. 10), serve for articulation with the sacrum coccyx. Sacral horns restrict sacral gap (Fig. 10) - exit the sacral canal.

Coccyx (Fig. 11) consists of 3-5 immature vertebrae (Fig. 11) with (except I) form oval bone bodies, completely ossify in a relatively late age. The body of a vertebra coccygeal I have directed the parties to the outgrowths (Fig. 11), which are the rudiments of the transverse processes, at the top of this vertebra are modified upper articular processes - coccygeal horn (Fig. 11), which are connected to the sacral horns. On the origin of the coccyx is a vestige of the caudal skeleton.

4 Chest

 

The rib cage consists of the edges connected to the front ends of the sternum, and back - with the thoracic vertebrae. The front surface of the rib cage, sternum, and provided the front ends of the ribs is much shorter than the back or side of its surface. The cavity of the chest, bounded below by the diaphragm, contains the vital organs - heart, lungs, major blood vessels and nerves. Also inside the chest (at the top of her third, just behind the breastbone) is the thymus (thymus).

 

The spacing between the components of the chest ribs occupy the intercostal muscles. Bunches of external and internal intercostal muscles run in different directions: the external intercostal muscles - from the bottom of the rib obliquely downward and forward, and the internal intercostal muscles - from the top edge obliquely upward and forward. Between the muscles is a thin layer of loose fibers, which are the intercostal nerves and blood vessels.

 

Newborns have a chest, much flattened laterally, and extended forward. With age, in the form of the thorax is clearly manifested sexual dimorphism: in males it is close to the cone-shaped, extending from the bottom; female breast is not only smaller in size, but also the different shape (expanding into the middle of the narrows and at the top and bottom parts).

5 sternum and ribs

Sternum (Fig. 12) is a long flat spongy bone forms, closing the chest in front. The structure of the sternum divided into three parts: the body of the sternum, sternum and arm xiphoid process, which with age (usually 30-35 years) are fused into a single bone (Fig. 12). At the junction of the sternal body with the handle of the sternum is directed forward angle of the sternum.

The handle has two pair of sternal notch on its lateral surfaces and a pair tenderloin on top. Cuts are on the side surfaces for articulation with the two upper pairs of ribs, a pair of cuts at the top of the handle, called the clavicular (Fig. 12) - to connect to the bones of the collarbone. The median notch, located between the clavicular, called the jugular (Fig. 12). The body of the sternum on each side also has a pair of cutting edge (Fig. 12), which are attached to the cartilaginous part of the II-VII pairs of ribs. The lower part of the sternum - xiphoid process - different people can differ greatly in size and shape, often has a hole in the center (the most common form of the xiphoid process is close to the triangle, often as the xiphoid process, bifurcated at the end).