Diaphysis The long, central shaft

Epiphysis : The rounded, flared end (or ends)

Diaphysis: The long, central shaft 

• The epiphysis refers to the rounded end of a long bone. Long bones typically have two epiphyses: a proximal epiphysis (near the body's center) and a distal epiphysis (away from the body's center).

• The diaphysis is the correct term for the long, central shaft of a bone. It is composed primarily of compact bone and usually contains the bone marrow cavity.