Which is the main shaft of the long bone?

Which is the main shaft of the long bone?

• A. Epiphysis
• B. Periosteum
• C. Diaphysis
• D. Medullary cavity

Answer: (C)

The diaphysis is the main shaft of a long bone. It’s the elongated, cylindrical portion that bears most of the bone’s load and is usually made of dense compact bone, extending between the two ends. The ends are the epiphyses, which form joints with other bones. The outer surface is covered by the periosteum, a fibrous membrane important for nourishment and growth, while the medullary cavity lies inside the shaft and contains bone marrow. So for the long-bone’s central, load-bearing portion, diaphysis is the correct term.

The diaphysis is the main shaft of a long bone. It’s the elongated, cylindrical portion that bears most of the bone’s load and is usually made of dense compact bone, extending between the two ends. The ends are the epiphyses, which form joints with other bones. The outer surface is covered by the periosteum, a fibrous membrane important for nourishment and growth, while the medullary cavity lies inside the shaft and contains bone marrow. So for the long-bone’s central, load-bearing portion, diaphysis is the correct term.