Final answer:
The fibula forms the lateral malleolus on the outer side of the ankle, while the tibia or shin bone is the main weight-bearing bone creating the medial malleolus on the inner side.
Step-by-step explanation:
The tibia, also known as the shin bone, forms the inner ankle bone called the medial malleolus. In contrast, the fibula, which is the smaller bone of the lower leg, forms the lateral malleolus. This bony structure is palpable on the lateral side of the ankle. The tibia and fibula are crucial for forming the ankle joint, with the tibia bearing most of the body's weight and the fibula serving as an attachment for muscles.