Pain on the inside of the ankle, known as medial ankle pain, is less frequent than outer ankle discomfort but often signals significant structural involvement. This complex region houses structures essential for foot support and movement, making persistent pain a sign of underlying issues. Unlike common lateral ankle sprains, medial ankle problems frequently indicate chronic overuse, degeneration, or high-energy trauma that affects mobility.
Anatomy of the Inner Ankle
The medial side of the ankle is defined by the bony prominence of the tibia, called the medial malleolus. This structure serves as an attachment point for soft tissues essential for stability.
The deltoid ligament complex is the primary ligamentous structure on the medial side. It consists of multiple strong bands that prevent the foot from rolling too far outward. The posterior tibial tendon runs just behind the malleolus and is a major supporting structure for the arch of the foot. The tibial nerve also passes through this region within the tarsal tunnel, carrying sensation to the sole of the foot. These components—bone, ligament, tendon, and nerve—are all potential sources of medial ankle pain when injured or compressed.
Posterior Tibial Tendon Dysfunction
Posterior Tibial Tendon Dysfunction (PTTD) is the most common cause of chronic medial ankle pain and is a progressive condition. The posterior tibial tendon acts as a dynamic stabilizer, supporting the arch during walking and standing. Dysfunction begins when the tendon becomes inflamed (tendonitis) due to overuse or degenerative changes.
As the tendon weakens, it loses its ability to support the arch, leading to a gradual collapse of the foot, often termed adult-acquired flatfoot. Pain is typically felt along the tendon, behind and below the medial malleolus, and worsens with activity like running or prolonged walking. In later stages, the arch flattens noticeably, and the heel may turn outward, sometimes shifting the pain to the outside of the ankle. The inability to perform a single-leg heel raise is a sign of the tendon’s failure. Early intervention is important because progression can lead to secondary arthritis in the surrounding joints.
Traumatic Injuries and Ligament Damage
Medial ankle pain can result from sudden, acute trauma, typically involving the deltoid ligament or bony structures. A deltoid ligament sprain is less common than an outer ankle sprain because the medial ligament is considerably stronger. It usually occurs from a forceful outward twisting motion of the foot. This injury requires significant force, and a severe sprain is often associated with fractures of the fibula.
Fractures of the medial malleolus (the end of the tibia) can result from direct impact or the forceful pull of the deltoid ligament during a severe ankle twist. Acute fractures cause immediate, severe pain and an inability to bear weight. A stress fracture of the medial malleolus develops gradually over weeks or months. This hairline crack is often seen in endurance athletes and results from repetitive, excessive stress placed on the bone during activities like running. The pain starts subtly, worsens during activity, and becomes a specific point of tenderness on the bony bump.
Nerve Compression and Chronic Joint Issues
Medial ankle discomfort can be caused by nerve compression or degenerative joint changes. Tarsal Tunnel Syndrome results from the compression of the tibial nerve as it passes through the tarsal tunnel. The tunnel is a confined space that can be constricted by swelling from an injury, a bone spur, or an abnormal foot structure like a flatfoot.
Symptoms of nerve compression are distinct from tendon pain, presenting as numbness, tingling, or a burning sensation that can radiate into the sole of the foot. This nerve pain can feel like an electric shock or pins and needles and may worsen with prolonged standing or at night.
Another source of chronic, deep aching pain is osteoarthritis in the ankle joint (talocrural joint) or the subtalar joint. Osteoarthritis causes the protective cartilage to wear away, leading to bone-on-bone friction and inflammation. The pain is typically worse in the morning or after periods of rest and is often a consequence of a prior ankle fracture or severe injury.
Knowing When to See a Doctor
While mild ankle pain may resolve with rest, certain signs indicate the need for professional medical evaluation. Seek medical attention if you experience an inability to bear weight immediately following an injury. Sudden or significant swelling, visible deformity, or pain accompanied by numbness, tingling, or a burning sensation also warrants a prompt visit, as these can suggest nerve involvement. If the pain persists or worsens after two or three days of home care, an assessment is necessary. Getting an accurate diagnosis early is important for conditions that require specific bracing or targeted physical therapy.