Diafízis

Diafízis refers to the shaft or central part of a long bone. It is the main or longest portion of the bone, typically cylindrical in shape. This region is primarily composed of compact bone, which provides strength and rigidity. Within the diaphysis, the medullary cavity, or marrow cavity, is located. This cavity contains bone marrow, which is responsible for producing blood cells. In children and adolescents, the medullary cavity is filled with red bone marrow, but in adults, it is largely replaced by yellow bone marrow, which is primarily composed of fat. The diaphysis is formed during the process of endochondral ossification, where cartilage is gradually replaced by bone. The outer surface of the diaphysis is covered by the periosteum, a membrane that contains blood vessels and nerves and plays a role in bone growth and repair. The inner surface of the medullary cavity is lined by the endosteum. Fractures that occur in the diaphysis are common and can vary in severity. The structural characteristics of the diaphysis are essential for bearing weight and facilitating movement in the skeletal system.