A malleolus is a bony prominence, or bump, on each side of your ankle. These are the knobby bones you can feel on the inner and outer sides of your ankle. There are three main malleoli:
Types of Malleoli
- Medial Malleolus: This is the bony prominence on the inner ankle. It's part of the tibia (shin bone).
- Lateral Malleolus: This is the bony prominence on the outer ankle. It's part of the fibula (the smaller bone in your lower leg).
- Posterior Malleolus: This is a less prominent bony projection on the back of the ankle, also part of the tibia. It is often involved in more complex ankle fractures.
The malleoli form an important part of the ankle joint, helping to stabilize it and provide support for weight-bearing. They are crucial for the range of motion and stability of your ankle. Fractures to these bony prominences are common ankle injuries. For example, a fracture of the lateral malleolus is a common type of ankle fracture, resulting from a fall or twisting injury.
The talus (ankle bone) sits between the malleoli and the foot bones. This articulation creates the ankle joint, allowing movement like bending your foot up and down (dorsiflexion and plantarflexion).
References support the definition and location of the malleoli within the ankle joint:
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The provided text mentions that the "knobby bones on the outside and the inside of the ankle are called malleoli." It further specifies the lateral malleolus as the end of the fibula and the medial malleolus as the inside part of the tibia. The posterior malleolus is also identified as the back part of the tibia.
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Wikipedia defines a malleolus as "the bony prominence on each side of the human ankle."
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Merriam-Webster Medical describes a malleolus as "an expanded projection or process at the distal end of the fibula or tibia at the level of the ankle."
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Several other resources (HSS, WebMD, AAOS, ScienceDirect) consistently reinforce this anatomical description, highlighting their role in ankle stability and common association with fractures.
