The structure indicated is the first metatarsal bone of the foot.

The foot contains three groups of bones:

1. Tarsals
2. Metatarsals
3. Phalanges

There are 7 tarsal bones, and 5 metatarsals. The metatarsals are numbered from 1 to 5 from medial to lateral, with the first metatarsal belonging to that of the great toe (hallux) and the 5^th metatarsal belonging to that of the little toe.

The metatarsals consist of the following parts:

• Base
• Shaft
• Head

Learn more about the anatomy of the bones of the foot in this anatomy tutorial.