< h2 class="pgc-h-arrow-right" > motion system</h2>
<h2 class= "pgc-h-arrow-right" > section 2 osteology</h2>
<h3 class= "pgc-h-arrow-right" > first, the general theory</h3>
Bone bone in adults is 206 pieces, according to the different parts, can be divided into trunk bone, skull, upper limb bone and lower limb bone four parts, of which 51 pieces of trunk bone, 29 pieces of skull (including 6 pieces of auditory ossicles), 64 pieces of upper limb bone, 62 pieces of lower limb bone. The weight of bone accounts for about 1/5 of body weight in adults and about 1/7 of newborns.
Human bones
Each piece of bone is an organ composed of bone tissue (including bone cells and bone), with a certain morphological structure, rich in blood vessels, lymphatic vessels and nerves, can continuously metabolize, has its growth and development process, and has the ability to repair, regenerate and reconstruct. Regular exercise promotes good development and stout bones, and osteoporosis occurs if used for a long time. Calcium and phosphorus in the bone are involved in the metabolism of calcium and phosphorus in the body and are in a constantly changing state. Therefore, bone is also a storage warehouse for calcium and phosphorus in the body.
< h4 class = "pgc-h-arrow-right" > (i) morphology of the bone</h4>
Form and function are closely related, due to different functions, bone has different forms, basically can be divided into long bone, short bone, flat bone and irregular bone four categories.
Morphology of the bone
1. The long bone is long-tubular, divided into two ends of the body, distributed in the limbs, and plays a leverage role in movement. The body is also known as the backbone, the bone is dense, and the tubular cavity inside the backbone is called the bone marrow cavity, which contains the bone marrow; there are 1 to 2 vascular in and out of the trophoblast hole on the surface of the backbone. The swelling of both ends is called the epiphyseum, which has a smooth articular surface and is covered with cartilage of the articular cartilage. In adolescence, there is a layer of cartilage between the diaphysis of the long bone and the epiphysis, called the epiphyseal cartilage. Epiphytic cartilage can continue to grow and ossify, so that the length of the bone increases. In adulthood, the epiphyseal cartilage ossified, and a linear mark is formed at the prophyphylaxial cartilage, called the epiphyseal line.
2. Short bone short bone short bone is generally rectangular, mostly distributed in groups in strong and flexible parts, such as wrist bone and tarsal bone.
3. Flat bone flat bone is plate-shaped, mainly involved in the wall of the body cavity, has a protective effect on the organs in the body cavity, such as the skull cap involved in the composition of the cranial cavity and protects the brain, the sternum and ribs participate in the formation of the chest cavity and protect the heart, lungs and so on.
4. Irregular bone irregular bone morphology irregular, such as vertebrae. Some irregular bones have air-containing cavities, called air-containing bones, such as the maxilla and sieve bones located around the nasal cavity, which can resonate when pronounced and reduce the weight of the bone.
< h4 class = "pgc-h-arrow-right" > (ii) bone structure</h4>
Each piece of bone is made up of bone, bone marrow, and periosteum, and has nerve and blood vessel distribution.
1. Bone bone substance is the main component of bone, divided into two types: bone dense and bone relaxant. The bone is dense and hard, forming the outer layer of the long backbone and other types of bone and epiphyseum. Bone floret is formed by the interweaving of many flaky and rod-like bony girders and is spongy. The trabecular arrangement is consistent with the direction of pressure and tension. Osteoporosis is distributed inside the epiphyseal long bones and other types of bone.
sclerotin
In the skull cap, bone compact matter constitutes the outer and inner plates. The bone rest of the skull cap is between the inner and outer plates, called the plate barrier.
diploe
2. Periosteum is a membrane composed of dense connective tissue, which is covered on the bone surface except for the joint surface. The periosteum is rich in nerves and blood vessels, which play an important role in bone nutrition, regeneration and sensation. Osteoblasts and osteoclasts in the inner layer of the periosteum, which have the function of producing new bone and destroying old bone, respectively, are most active in the occurrence, regeneration, modification and repair of bone. When the periosteum is peeled off, the bone is not easy to repair, and may even necrosis, so the periosteum should be preserved as much as possible during surgery.
periosteum
3. Bone marrow bone marrow is filled in the bone marrow cavity and bone rest space of long bones, and is divided into red bone marrow and yellow bone marrow. The red bone marrow contains a large number of red blood cells and some white blood cells at different stages of development, which are red and have hematopoietic function; the yellow bone marrow contains a large amount of adipose tissue, yellow, and has no hematopoietic function. The bones of fetuses and young children are full of red bone marrow. After the age of 5, the red bone marrow in the bone marrow cavity of the long bone is gradually replaced by adipose tissue and converted into yellow bone marrow, and the red bone marrow remains in the cancellous mass of various types of bone. When chronic blood loss is excessive or severe anemia, the yellow bone marrow can be converted into red bone marrow and restore hematopoietic function. When a bone marrow examination is required clinically, bone marrow puncture is often performed at the anterior superior iliac spine or posterior superior iliac spine.
On the joint surface of the bone, the joint cartilage composed of transparent cartilage is covered, which reduces friction and increases the flexibility of joint movement.
marrow