(from the Greek kyphos – bent, bent, curved, or from the Latin kyphosis – round back) is the bend of the spine in the sagittal plane, reversed by the convex posteriorly. A distinction is made between physiological and pathological kyphosis. Physiological thoracic and sacral kyphosis are formed in childhood, in adults the curves of the spine are fixed, in the elderly and senile age thoracic kyphosis usually increases. Pathological kyphosis becomes when its magnitude is greater or it occurs in an atypical place, for example, in the lumbar spine. Pathological kyphosis can be functional (not fixed) and fixed. The first occurs with uncompensated visual impairment, posture disorders, etc., with targeted treatment it can pass without a trace. The main difference between fixed kyphoses is that they do not disappear or decrease in the horizontal position of a person.