What is the spine of a bone?

• A. A long, thin projection that serves as a muscular attachment site
• B. The cartilaginous end of a bone
• C. A rounded end forming a joint
• D. The hollow cavity inside bone

Answer: (A)

A spine on a bone is a long, thin projection that serves as a muscular attachment site. This slender projection provides a lever-like point where muscles and ligaments anchor, helping to move and stabilize the bone. It’s not the end of the bone that forms a joint (that would be an articular end such as a head or condyle), not the hollow cavity inside the bone (the medullary cavity), and not the cartilaginous end (epiphysis). For example, the spine of the scapula and the vertebral spinous processes are prominent projections that muscles pull on to create movement and posture.