What is the diaphysis of a bone?

The diaphysis of a bone refers specifically to the shaft or central part of a long bone. In anatomical terms, long bones are characterized by a tubular shape that consists of a long, narrow section known as the diaphysis, which is surrounded by a thick layer of compact bone. This shaft plays a crucial role in supporting the weight of the body and facilitating movement, as well as serving as a site for muscle attachment.

The diaphysis is contrasted with the ends of long bones, called the epiphyses, which are involved in joint formation and contain spongy bone. The outer covering of a bone, known as the periosteum, serves important functions including the growth and repair of bone, but it is not the diaphysis. Similarly, cartilage at the joint is essential for cushioning and facilitating movement but does not relate to the diaphysis itself.