An osteochondral lesion of the medial talar dome may sound alarming, but let’s break down what it means. Osteochondral refers to the bone (osteo) and cartilage (chondral) surrounding it. The talar dome is the cartilage that covers the talus, or the bottom bone of your ankle joint. Medial refers to the inside edge of the body part, as opposed to the lateral or outside edge. So an osteochondral lesion of the medial talar dome is an injury to the cartilage in your ankle joint. Injuries to the bone and overlying cartilage can include fractures, tearing or crushing, and even cysts in the cartilage.