Q.Draw and label the structure of a typical Long Bone.

A typical long bone consists of a central shaft (diaphysis) and two expanded ends (epiphyses), with an outer covering (periosteum), a central marrow-filled cavity (medullary cavity, lined by endosteum), and articular cartilage capping the joint surfaces; we describe and label these parts in text, since we are not able to provide a hand-drawn diagram in this format.

The structure of a typical long bone (for example, the femur or humerus) can be described part by part, from one end to the other:

1. Epiphysis (proximal and distal) — the two expanded, knob-like ends of the bone. They are made largely of spongy (cancellous) bone internally, which contains red bone marrow (site of blood cell formation), and their outer surface at the joint is covered by a smooth layer of articular (hyaline) cartilage that reduces friction where the bone meets another bone at a joint.

2. Epiphyseal line/plate — the narrow zone between each epiphysis and the shaft; in a growing bone this is a cartilaginous growth plate, and in an adult (once growth is complete) it becomes a thin bony line.

3. Diaphysis — the long, tubular shaft of the bone, made of compact (dense) bone that gives strength to withstand bending and twisting forces during movement.

4. Medullary cavity — the hollow central cavity running through the diaphysis, containing yellow (fatty) bone marrow in adults.

5. Endosteum — the thin membrane lining the inner surface of the medullary cavity.

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