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The humerus cut open. Labels: a, marrow cavity; b, hard bone; c, spongy bone; d, cartilage.

The Humerus

The humerus cut open. Labels: a, marrow cavity; b, hard bone; c, spongy bone; d, cartilage.

Here you see the thigh bone on the left and the arm bone on the right. In both, the shaft is hollow, while the large ends are more dense. In the living bone, bone marrow is found in the hollow area which serves in blood cell production.

Thigh Bone and Arm Bone

Here you see the thigh bone on the left and the arm bone on the right. In both, the shaft is hollow,…