Final answer:
The periosteum is a fibrous membrane that surrounds the bone surface not covered by articular cartilage. It nourishes the bone and serves as an attachment point for ligaments and tendons. It is critical for bone growth and repair.
Step-by-step explanation:
A tough connective tissue sheath and its associated blood supply that surrounds the bone surface wherever it is not covered by articular cartilage is known as the periosteum. The periosteum is a fibrous membrane that contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. It covers the entire outer surface of the bone except at the joints, where the bones are covered with articular cartilage, a thin layer of cartilage that reduces friction and acts as a shock absorber.
The periosteum is essential for the attachment of ligaments and tendons to the bone. Moreover, it plays a pivotal role in bone growth, repair, and remodeling due to its rich supply of blood vessels and the presence of osteoblasts, cells that synthesize new bone matrix. The endosteum, which lines the inner surface of the bone and the medullary cavity, is also vital in these processes.