The structure of the spine

The spine is made ​​up of people 33 - 34 vertebrae, which are connected by joints, ligaments and intervertebral discs. 6 - 9 fused vertebrae forming the sacrum and coccyx. There are five parts of the spine: cervical, consisting of seven vertebrae, rib - 12, lumbar - of 5, sacral - 5 and coccyx, consisting of 4 - 5 vertebrae.

Vertebra consists of a body facing anteriorly and connected with it arc vertebra. The body and vertebral arch vertebral restrict the opening.Vertebrates make holes all the vertebrae the spinal canal, which houses the spinal cord. From the spinal cord through the spinal nerves leave the hole. From the arch of each vertebra depart to 7 branches. In the pair of directed transverse processes. Each vertebra is connected to the upper and lower adjacent vertebrae by means of two lower and two upper articular processes. From the middle of the arc to the rear unpaired spinous process. In various parts of the spine spinous processes have their own characteristics. In the cervical region they are short, spinous process of the seventh cervical vertebra is longer than the others and is easily detectable under the skin. In the thoracic spinous processes of the longest and are directed downwards, in the lumbar region they are wide and laid back. The dimensions of the vertebral bodies depend on the magnitude of the burden on them, they are the lowest in the cervical region and the largest in the lumbar. top two cervical vertebrae are used for articulation with the skull and have significant differences in the structure. On the body and transverse processes of thoracic vertebrae are edge pits for articulation with the ribs. Sacrum consists of five sacral vertebrae, which in 20 years' fused into one bone that attaches to the spine of particular strength.

The vertebrae are interconnected by means of inter ¬ vertebrate cartilage, ligaments and joints. Vertebral bodies are connected by cartilaginousintervertebral discs . Each of them consists of an outer fibrous ring and the inner nucleus pulposus. The total height of these disks is a quarter of the entire length of the spine. Interestingly, during the day gelatinous nucleus loses fluid, cartilage and intervertebral flatten ¬ Xia. As a result, man is the evening of 2 cm shorter than in the morning, the same thing occurs with prolonged ¬ load on the spine.

Along the entire length of the spine vertebral bodies and intervertebral discs are connected with long anterior and posterior longitudinal ligament.Above the tops of the spinous processes along the entire length is spinous ligament. In addition, the arc, transverse and spinous processes of adjacent vertebrae are connected by short ligaments. 

Human spine has several natural curves. curve, convexity ago, called kyphosis, the curve, convexity forward - lordosis. The man has two kyphosis (thoracic and sacral), and two lordosis (cervical and lumbar). In addition, the spine is normal can have a lateral bending (scoliosis), which appears due to the varying length of the lower limbs and the development of different muscles on different sides of the body. This scoliosis should not be confused with scoliosis as a disease, it can be attributed to violations of posture. Curves of the spine provide mitigation of shocks and tremors of the body when running and walking. Despite the low mobility of the intervertebral joints, the spine on the whole quite mobile, especially the lumbar region.

In the spinal canal is the spinal cord . At the top it goes to the brain, and the bottom ends with special reference to the level of the 2nd lumbar vertebra. Through the spinal cord central canal is filled with cerebrospinal fluid.

The spinal cord consists of 31 - 33 segments, each of which has two pairs of nerve roots: anterior (motor), by which impulses from the cells of the spinal cord are transmitted to the periphery (to the skeletal muscles, the muscles of blood vessels, internal organs), and posterior (sensory) by which impulses from the receptors of the skin, muscles, internal organs are passed into the spinal cord. The anterior and posterior roots on each side of the spinal cord, connecting with each other to form 31 mixed pair of spinal nerves. The spinal cord is involved in most of the reflex reactions of the organism, the most complex spinal reflex reactions are controlled by the brain.

For a complete familiarity with the structure of the spine look muscular system, limiting brief analysis of the back muscles.

All human skeletal muscles are composed of so-called striated muscle tissue, the reduction of these muscles occurs randomly. The simplest form of the muscle is fusiform shape. The middle part is called the belly muscles, at both ends of the muscle goes into a tendon which is attached to the bones, reducing the muscle is shortened, and the attachment points closer to each other.

Muscles engaged in opposing the action, called antagonists, such as the forearm flexor and extensor (respectively, the biceps and triceps). To carry out any movement always requires teamwork antagonist muscle for complex movements require the work of an entire group of muscles.There are long, wide and short muscles. Long muscles are located mainly on the limbs, where a large amount of movement. Short muscles especially a lot of deep back muscles. Chi ¬ rokie muscles located in the area of ​​the body: chest, abdomen and back. 

Back muscles are divided into superficial and deep. To the superficial muscles include trapezius, latissimus, rhomboid major and minor, muscle lifting the shoulder blade, upper and lower posterior serratus. Trapezius muscle starts from the occipital bone and the spinous processes of all thoracic vertebrae, is attached to the keys ¬ Tse and shoulder blade. The upper part of the muscle raises the shoulder blade, lower - it lowers the average of the blade closer to the spine. Latissimus dorsi muscle comes from the spinous processes of lower six thoracic and all the vertebrae are ¬ ary, on the iliac crest and attaches to the humerus. The muscle pulls the shoulder and arm back while rotating it inward. Rhomboids pick up shovel, bring it closer to the midline. The upper posterior serratus raised edges, the bottom drops them, ensuring the participation in the act of inspiration.

The deep back muscles form a two tract - lateral and medial, ¬ nye located on either side near the spine along its entire length from the occiput to the sacrum. Lateral tract ¬ General will make more than superficial long muscles that make up muscle, spinal straightening ¬ nick. The muscles of the medial tract (cross-awned) lie deeper than others, they represent a group of short muscle bundles, and burn through the vertebrae. In the back of the neck over the two paths is re ¬ mennaya muscle head and neck.

In addition to these muscles, forming the back part of the abdominal wall square loin muscle, which relates to the anatomy of the abdominal muscles.

Scoliosis affects other elements of the musculoskeletal system, which remained outside of this description: the clavicle and scapula, chest and ribs, pelvic area.