Metacarpal bones

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Description:

The metacarpal bones, like the metatarsal bones, are miniature long bones because of the presence of a medullary cavity. They are numbered one to five from lateral (thumb-side) to medial. They share a basic design. Each metacarpal bone has a rounded distal head that forms the large knuckles of the hand, a narrowed shaft with a slight longitudinally concave palmar surface, and an expanded proximal base.