What is the term for the end or head at the extremity of a long bone?

The term for the end or head at the extremity of a long bone is called the epiphysis. This area is comprised of spongy bone covered by a thin layer of compact bone and is essential for joint function, as it helps form the joint surface and articulates with adjacent bones. The epiphysis also plays a crucial role in the growth of long bones during childhood and adolescence, as it contains the growth plate—areas of cartilage that allow the bone to lengthen as a person matures.

In contrast, the diaphysis refers to the long shaft of the bone, which is primarily made of compact bone and serves as the support structure. The metaphysis is the region where the diaphysis meets the epiphysis, often involved in the growth process, but it is not the end part itself. The term proximal junction is not commonly used in relation to long bones and does not specifically refer to any recognized anatomical structure associated with the ends of bones, making epiphysis the accurate choice for this question.