The spine is located in the center of the back of the body. The spine plays a role as a supporter of the head and the central axis of the trunk, supporting body weight and participating in the composition of the thoracic, abdominal and pelvic cavities, protecting the internal organs of the body cavity, especially the spinal cord. The adult spine consists of 24 separate vertebrae, a sacrum and a coccyx. According to the different parts of the 24 independent vertebrae, there are 7 cervical, 12 thoracic and 5 lumbar vertebrae. The sacrum consists of 5 sacral vertebrae fused to each other and the coccyx consists of 3-5 caudal vertebrae. Each vertebra can be divided into a vertebral body located in the front and a vertebral arch located in the back. The adjacent vertebrae are linked to each other by the intervertebral discs, which are gradually thickened from top to bottom and act as elastic cushions. Along the entire spine, there are two strong top-down longitudinal ligaments, the anterior and posterior longitudinal ligaments, as well as other ligaments of varying lengths and large and small muscles. The spine is composed of independent vertebrae, plus ligaments, muscles, intervertebral discs will be connected to each vertebrae, becoming a whole, just like the chain of a bicycle, loop, which ensures the flexibility of human neck, chest, waist activities, people can freely according to different needs face forward and backward, left and right bending, called at ease, as you wish. The human spine is not as straight as a pole, but according to the special situation of the human body, there are four bends, from the side looks S-shaped, two of which are primary lordosis, two secondary lordosis. The posterior convexity of the thoracic spine is the result of the anterior narrowing and posterior widening of the thoracic vertebrae, while the secondary anterior convexity of the neck is mainly composed of the anterior wide and posterior narrowing of the intervertebral discs, with the vertebrae being equal in height or slightly shorter in front. In the case of lumbar lordosis, in addition to the anterior height of the intervertebral disc and posterior shortening, the lumbar 4 and lumbar 5 vertebrae also become anteriorly high and posteriorly short, the lumbar 3 vertebrae are variable and still mostly square, while the lumbar 1 and 2 vertebrae still adapt to the posterior convexity of the thoracolumbar segment and are posteriorly high and anteriorly short. There are some differences in the curvature of the lumbar vertebrae in terms of gender, and the female ones are generally larger than the male ones. The presence of normal physiological curvature is an indication of the stability and balance of the spine itself. The functional role of the spine 1, skeletal support role. The spine is the pillar of the human trunk, it is located in the back of the neck, trunk and pelvis is located in the middle, plays a role in supporting the head and composition, support the role of the thoracic cavity, abdominal cavity, pelvic organs, but also the upper and lower limbs supporters. 2, safety and protection role. The spine has four physiological curvature (cervical, thoracic, lumbar and sacral curvature), so that the spine is like a large spring, increasing the ability to cushion shock and enhance stability. During jumping or strenuous exercise, the intervertebral discs absorb shock and prevent damage to the skull and brain. Also plays a protective role for the spinal cord, central nervous system and internal organs. 3, sports balance role. The upper end of the spine supports the head by the occipital bone, and the thorax is formed by the rib cage in the chest. The upper limbs are connected to the spine by the ribs, clavicle and sternum and muscles; the lower limbs are connected to the spine by the pelvis. The human body trunk forward flexion, backward extension, lateral flexion, rotation and other movements, as well as various activities of the upper and lower extremities, are regulated through the spine to maintain balance. 4, the role of the nerve conduction center. The human peripheral nervous system is composed of autonomic, sensory and motor nerves, which are distributed throughout the body through the 31 pairs of nerve roots in the spine.