In a long bone, which region is the main shaft?

In a long bone, which region is the main shaft?

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

Answer: (C)

The main shaft of a long bone is the diaphysis. This central region runs between the two ends and is typically built mainly from compact bone to provide strength with lightweight structure. It houses the medullary cavity inside, which contains marrow. The outer surface is coated by the periosteum, a fibrous layer important for growth and healing. The ends of the bone are the epiphyses, which contain more spongy bone and form joints. So, when identifying the shaft, focus on the diaphysis as the long bone’s central, cylindrical portion.

The main shaft of a long bone is the diaphysis. This central region runs between the two ends and is typically built mainly from compact bone to provide strength with lightweight structure. It houses the medullary cavity inside, which contains marrow. The outer surface is coated by the periosteum, a fibrous layer important for growth and healing. The ends of the bone are the epiphyses, which contain more spongy bone and form joints. So, when identifying the shaft, focus on the diaphysis as the long bone’s central, cylindrical portion.