What is the name of the outer protrusion on the side of the ankle?

The outer protrusion on the side of the ankle is referred to as the lateral malleolus. This structure is part of the fibula, one of the two long bones in the lower leg. The lateral malleolus is the bony prominence that you can feel on the outside of your ankle, and it plays a critical role in stabilizing the ankle joint. It helps to form the ankle's mortise (the cavity into which the talus fits), providing support for movements such as walking and running.

The medial malleolus, on the other hand, is the bony prominence located on the inner side of the ankle, and does not pertain to the outer side. The calcaneus is the heel bone, and while it is important in the structure of the foot, it is not involved in the anatomy of the ankle joint like the lateral malleolus is. The talus is the ankle bone that sits above the heel bone but does not protrude on the outer side of the ankle. Understanding the specific anatomical terms and their locations is crucial for defining and recognizing structures related to the ankle.