Which bones are thin and flat, consisting of a layer of spongy bone between two layers of compact bone?

Which bones are thin and flat, consisting of a layer of spongy bone between two layers of compact bone?

• A. Flat bone
• B. Long bone
• C. Irregular bone
• D. Sesamoid bone

Answer: (A)

A flat bone is thin and flat and features a layer of spongy bone between two layers of compact bone. This sandwich-like arrangement, with the outer and inner compact layers protecting the inner tissue and the middle spongy bone (often called diploë in skull bones) providing some lightness and space for marrow, is the hallmark of flat bones. You’ll find this design in structures like the bones of the skull, sternum, ribs, and scapula. In contrast, long bones have a prominent shaft of compact bone surrounding a medullary cavity, irregular bones have varied shapes, and sesamoid bones form within tendons. So the described bones fit the flat bone category.

A flat bone is thin and flat and features a layer of spongy bone between two layers of compact bone. This sandwich-like arrangement, with the outer and inner compact layers protecting the inner tissue and the middle spongy bone (often called diploë in skull bones) providing some lightness and space for marrow, is the hallmark of flat bones. You’ll find this design in structures like the bones of the skull, sternum, ribs, and scapula. In contrast, long bones have a prominent shaft of compact bone surrounding a medullary cavity, irregular bones have varied shapes, and sesamoid bones form within tendons. So the described bones fit the flat bone category.