What curves does the spine have and what functions do they perform?

The spine is the main structure of the human musculoskeletal system, it has a curved shape. The backward bend is called kyphosis, there are two such bends (sacral, sternal), and the forward bend is called lordosis, there are also two of them (lumbar and cervical). These bends are called physiological, since they are necessary for the correct functioning of the entire musculoskeletal system, contribute to an even distribution of the load, as well as shock absorption and reduce vibration when walking, and helps to maintain an upright position and balance when walking.