What is the name for the expanded end of a long bone where red blood cells are formed?

The expanded end of a long bone, known as the epiphysis, plays a crucial role in the formation of red blood cells. This region is rich in red marrow, which is responsible for hematopoiesis, the process of blood cell production. In adults, this occurs predominantly in the flat bones and the epiphyses of long bones. The spongy bone structure found in the epiphysis provides a conducive environment for the formation and maturation of these blood cells.

In contrast, the diaphysis refers to the long, tubular shaft of the bone, primarily composed of compact bone that supports weight and provides leverage for movement. The diaphysis plate is a term often associated with the growth plate area, critical during development but not specifically where red blood cells are formed. The term "bone head" is not typically used in anatomical terminology to describe a specific part of a long bone, leading to potential confusion. Therefore, the epiphysis is the distinct anatomical structure associated with the formation of red blood cells.