Which bone forms the rounded element of the ankle joint and connects with the tibia and fibula?

• A. Talus
• B. Calcaneus
• C. Malleolus
• D. Tarsus

Answer: (A)

In the ankle, the rounded bone that forms the main articular surface with the leg bones is the talus. Its upper surface fits between the medial malleolus of the tibia and the lateral malleolus of the fibula, creating the ankle joint (talocrural joint) that allows up-and-down movement. The calcaneus (heel bone) sits below the talus and forms the subtalar joint, while the malleoli are the ankle projections that stabilize the joint, not the rounded element itself. The tarsus refers to the group of foot bones, not a single bone. So the talus is the bone that forms the rounded element and connects with both the tibia and fibula.