It is often heard that old people say, "people are old, short and hunchbacked." This phenomenon is quite common and does exist. In severe cases, a person's height at the age of 80 will be 10 ~ 15cm shorter than that when he is young. Why?
The height of a person is mainly determined by the length of the spine and lower limbs. The adult spine consists of 26 vertebrae and intervertebral discs between them. Most people will feel that their waist and back are straight. In fact, from the side, the spine is not straight, but there are four physiological bends, two anterior concave and two kyphosis. After offsetting each other, it looks straight as a whole. Among the four physiological bends, the thoracic kyphosis and lumbar lordosis have a great impact on height.
In adulthood, with the growth of age, degenerative changes will occur in the joints of the whole body, the articular cartilage becomes thinner due to wear and degradation, and the joint space becomes narrow. As a special joint between vertebrae, intervertebral disc is no exception. Moreover, older people will have osteoporosis more or less. In severe cases, the spine and vertebrae (especially thoracic vertebrae and lumbar vertebrae) will be overwhelmed by the pressure of weight, and will change from a square to a wedge with low front and high rear.
Due to the wedge-shaped change of multiple vertebrae caused by osteoporosis, thoracic kyphosis increases and lumbar lordosis decreases, which finally makes the whole spine short in the first half and high in the second half, which is reflected in the shape of the body. The hump shortens the relative length of the spine and makes people shorter when standing.
There are other reasons for being shorter, the most important of which is the shrinkage and thinning of three intervertebral discs of cervical spine, thoracic spine and lumbar spine. According to the average thinning of each intervertebral disc by 3 ~ 4 mm, the spine will be shortened by about 10 cm. In addition, the hip joint, knee joint and ankle joint space of the lower limbs are narrow, especially when the knee joint becomes narrow and becomes a coiled leg, the height will be further reduced.