Ralph Hutchings

Image 62 of 74
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Section through the upper (proximal) end of the human humerus or arm bone that forms part of the shoulder joint. The bone has been sectioned to show the trabeculae that form the internal supportive structure of long bones. In old age, the density of trabeculae decreases (osteoporosis) and bones become vulnerable to fracture. The ends of long bones that are filled with trabeculae are called spongy or cancellous bone, and the outside is called compact bone.