Epiphysis

The epiphysis is the rounded end of a long bone, at its joint with adjacent bone(s). Between the epiphysis and diaphysis (the long midsection of the long bone) lies the metaphysis, including the epiphyseal plate (growth plate). At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal plate, known as bone.
The epiphysis is filled with red bone marrow, which produces erythrocytes (red blood cells).
Structure.
There are four types of epiphysis:
Bones with an epiphysis.
There are many bones that contain an epiphysis:
Pseudo-epiphysis.
A "pseudo-epiphysis" is an epiphysis-looking end of a bone where an epiphysis is not normally located. A pseudo-epiphysis is delineated by a "transverse notch", looking similar to a "growth plate". However, these transverse notches lack the typical cell columns found in normal growth plates, and do not contribute significantly to longitudinal bone growth. Pseudo-epiphyses are found at the distal end of the first metacarpal bone in 80% of the normal population, and at the proximal end of the second metacarpal in 60%.
Clinical significance.
Pathologies of the epiphysis include avascular necrosis and osteochondritis dissecans (OCD). OCD involves the subchondral bone.
Epiphyseal lesions include chondroblastoma and giant-cell tumor.