What is the thin vascular membrane covering cavities within bone called?

What is the thin vascular membrane covering cavities within bone called?

• A. Calcaneus
• B. Endosteum
• C. -otomy
• D. Cost/o

Answer: (B)

Endosteum is the thin, vascular membrane that lines the inner surfaces of bone, including the medullary (marrow) cavity and other internal spaces. It contains osteogenic cells that can become osteoblasts or osteoclasts, supporting bone growth, repair, and remodeling from within. This inner lining is different from the periosteum, which covers the outer surface of bone. The other terms refer to a specific bone (calcaneus), a surgical suffix (-otomy), or a rib-related prefix (cost/o), not to the inner lining of bone cavities.

Endosteum is the thin, vascular membrane that lines the inner surfaces of bone, including the medullary (marrow) cavity and other internal spaces. It contains osteogenic cells that can become osteoblasts or osteoclasts, supporting bone growth, repair, and remodeling from within. This inner lining is different from the periosteum, which covers the outer surface of bone. The other terms refer to a specific bone (calcaneus), a surgical suffix (-otomy), or a rib-related prefix (cost/o), not to the inner lining of bone cavities.