The inside of your ankle is a complex anatomical area that supports movement and stability. This region involves an intricate network of bones, ligaments, tendons, nerves, and blood vessels, all working together to facilitate the diverse functions of the foot and ankle.
The Medial Malleolus: The Bony Landmark
The prominent bony protrusion on the inner side of your ankle is the medial malleolus (Latin: malleolus medialis). This structure is the lower, extended end of the tibia, or shin bone, and forms a significant part of the ankle joint, articulating with the talus bone of the foot.
The medial malleolus serves as an anatomical landmark, providing attachment points for ligaments and muscles that contribute to ankle stability and movement. Injuries to this bony structure can impact ankle function.
Stabilizing Structures: Ligaments and Tendons
The stability of the inner ankle relies on ligaments and tendons. The deltoid ligament complex (Latin: ligamentum deltoideum) is a robust, triangular band on the medial side of the ankle. It consists of multiple parts that fan out from the medial malleolus to attach to bones in the foot, such as the talus, calcaneus, and navicular bones, helping stabilize the ankle joint and resist excessive outward movement (eversion).
Several tendons traverse the inner ankle, passing behind the medial malleolus. These include the posterior tibialis tendon (Latin: musculus tibialis posterior), the flexor digitorum longus tendon (Latin: musculus flexor digitorum longus), and the flexor hallucis longus tendon (Latin: musculus flexor hallucis longus).
The posterior tibialis tendon supports the arch of the foot and assists in plantarflexion and inversion of the ankle. The flexor digitorum longus helps flex the second through fifth toes, while the flexor hallucis longus flexes the big toe.
Passing Through: Nerves and Blood Vessels
The inner ankle region serves as a passageway for neurovascular structures within the tarsal tunnel. This tunnel is located behind the medial malleolus and is formed by bones and a tough ligament called the flexor retinaculum.
Within the tarsal tunnel, the tibial nerve (Latin: nervus tibialis) is found, along with the posterior tibial artery (Latin: arteria tibialis posterior) and accompanying veins. The tibial nerve provides sensation to the sole of the foot and controls many of the foot’s intrinsic muscles. The posterior tibial artery supplies blood to various parts of the lower leg and foot.
Common Conditions Affecting the Inner Ankle
Medial ankle sprains involve injury to the deltoid ligament. They occur from excessive outward twisting of the foot (eversion) and can result in pain, swelling, and bruising on the inner ankle.
Posterior tibial tendon dysfunction (PTTD) occurs when the posterior tibialis tendon becomes inflamed or damaged, leading to pain and swelling along the inside of the foot and ankle. As PTTD progresses, it can cause the arch of the foot to flatten and the ankle to roll inward.
Tarsal tunnel syndrome results from compression or damage to the tibial nerve as it passes through the tarsal tunnel. Symptoms include pain, numbness, burning, or tingling sensations in the bottom of the foot and toes, which can worsen with activity.