From Wikipedia, the free encyclopedia
Jump to: navigation, search
Structure of a Long Bone.png
A long bone, with diaphysis labeled at right.
MeSH A02.835.232.169
TA A02.0.00.017
FMA 24013
Anatomical terminology

The diaphysis (/dˈæfss/[1][2]) is the main or midsection (shaft) of a long bone. It is made up of cortical bone and usually contains bone marrow and adipose tissue (fat).

It is a middle tubular part composed of compact bone which surrounds a central marrow cavity which contains red or yellow marrow. In diaphysis, primary ossification occurs.

Ewing's sarcoma tends to occur at the diaphysis.[3]

Additional images[edit]

See also[edit]


  1. ^ OED 2nd edition, 1989, as /dˈæfɪsɪs/.
  2. ^ Entry "diaphysis" in Merriam-Webster Online Dictionary.
  3. ^ Physical Medicine and Rehabilitation Board Review, Cuccurullo