According to WebMD.com, the medial malleolus is a protuberance seen and felt on the inside part of the ankle at the bottom of the leg bone. The medial malleolus is a point where the deltoid ligament connects the tibia to the foot and allows the ankle to move while keeping the foot and leg together.
The inner surface of the medial malleolus is covered with cartilage and allows the talus, or upper bone of the foot, to articulate properly. This inner section allows the deltoid ligament to attach to the leg bone. A tendon is also attached to the posterior portion of the medial malleolus.
Fractures of this part of the ankle occur when the lower tibia or fibula breaks, or when ankle ligaments are injured. Nonsurgical treatments include a brace or cast that can be in place for up to six weeks. Surgical solutions for breaks of the medial malleolus include inserting plates and screws to graft another bone to the ankle joint. Grafting ensures the bone will be strong enough to support the weight of the leg attached to the ankle.
There are three malleoli in the ankle. The posterior malleolus is at the back of the ankle, and the lateral malleolus connects to the fibula on the outside part of the human ankle. These three protuberances are part of the ankle, the joint that allows up and down movement of the foot.