The structure indicated is the talus bone of the foot.
The foot contains three groups of bones:
The talus is one of seven tarsal bones. There are three groups of tarsal bones:
- Proximal group
- Intermediate group
- Distal group
There are two bones in the proximal group of tarsal bones: the talus and the calcaneus. The calcaneus is the largest tarsal bone and forms the heel through its posterior projection. The talus articulates with the medial malleolus of the tibia and the lateral malleolus of the fibula to form the ankle joint. In addition, it articulates with two other tarsal bones: the calcaneus inferiorly, and the navicular anteriorly.
The talus consists of the following main components:
- Head: contains facets for articulation with navicular and calcaneus
- Body: elevated trochlear surface articulates with inferior end of tibia
Learn more about the bones of the foot in this anatomy tutorial.