The term "epidiaphysis" is not commonly used in anatomical terminology. However, it may refer to the regions of a long bone, specifically the epiphysis (the rounded end of a long bone) and diaphysis (the main or central shaft of the bone). The epiphysis is involved in joint movement and the formation of bone, while the diaphysis primarily provides structural support. If you meant a different term, please clarify for a more accurate response.