Final answer:
The expanded portion at the end of most bones that articulates with another bone to form a joint is called the epiphysis.
Step-by-step explanation:
At the end of most bones, there is an expanded portion that articulates with another bone to form a joint. This expanded portion is called the epiphysis. It is wider than the shaft of the bone and is filled with spongy bone and red marrow. The epiphysis meets the diaphysis at the metaphysis, which features the epiphyseal plate, a region essential for bone growth in length.
Once growth in length is complete, the epiphyseal plate transforms into an epiphyseal line. The epiphyses play a key role in articulations, that is, where two bones meet to form joints.