Pain on the inside of your ankle typically comes from one of a handful of structures packed into a small space: a key tendon that supports your arch, a thick fan-shaped ligament, or a nerve running through a narrow tunnel behind the ankle bone. The most common culprit is the posterior tibial tendon, but the cause depends on how the pain started, what it feels like, and what makes it worse.
What’s on the Inside of Your Ankle
The bony bump on the inner side of your ankle is the medial malleolus, the bottom end of your shinbone. Wrapping around and beneath it are several structures that can produce pain when irritated or injured. The deltoid ligament is a strong, fan-shaped band that connects the medial malleolus to three bones in your foot. It prevents your ankle from rolling inward and is significantly stronger than the ligaments on the outer side, which is why inner ankle sprains are far less common than outer ones.
Running just behind and beneath the medial malleolus is the posterior tibial tendon. This tendon is the primary support for your foot’s arch, and it works hard every time you walk, run, or push off the ground. Alongside it sit two other tendons and the tibial nerve, all passing through a tight corridor of bone and tissue called the tarsal tunnel. When any of these structures become inflamed, torn, or compressed, you feel it on the inside of your ankle.
Posterior Tibial Tendon Problems
This is the single most common reason for chronic inner ankle pain in adults. The posterior tibial tendon can become inflamed (tendonitis) or, over time, progressively weaken and degenerate. Doctors stage the condition based on how much structural change has occurred in your foot:
- Stage 1: The tendon is inflamed but your foot shape is still normal. You can rise onto your toes, though it may hurt. Pain tends to sit along the inner ankle and into the arch, especially after activity.
- Stage 2: The tendon has stretched or partially torn, and your arch starts to flatten. Your foot begins turning outward. If someone stands behind you, they can see more toes peeking out on the affected side than normal.
- Stage 3: The arch has fully collapsed and become rigid. Arthritis develops in the joints of the hindfoot.
- Stage 4: The ankle joint itself shifts out of alignment, with arthritis visible on imaging.
Most people who search for inner ankle pain are in stage 1 or early stage 2. The pain often builds gradually over weeks or months rather than starting with a single injury. It’s worse during or after walking, running, or standing for long periods, and it may improve with rest. You might also notice mild swelling along the inner ankle. If you already have flat feet or tend to overpronate (your foot rolls inward too much when you walk), you’re at higher risk because those patterns put extra load on this tendon with every step.
Early-stage posterior tibial tendonitis generally responds well to rest, supportive footwear, and arch-supporting insoles or custom orthotics. A structured physical therapy program focused on strengthening the tendon and the muscles around your ankle is the cornerstone of recovery. In more advanced cases, a walking boot or brace may be needed to take stress off the tendon for several weeks. Surgery becomes an option only when conservative treatment fails and the foot’s structure has changed significantly.
Deltoid Ligament Sprains
A deltoid ligament sprain causes sudden pain on the inside of your ankle after a specific injury, usually rolling your ankle inward. This type of sprain accounts for only about 15% of all ankle sprains because the deltoid ligament is substantially stronger than the ligaments on the outer side. When it does happen, it’s often the result of a direct impact to the ankle rather than a simple misstep, and it frequently occurs alongside a fracture on the outer ankle.
Signs of a deltoid sprain include pain and tenderness directly over the inner ankle bone, swelling or bruising on the medial side, and difficulty putting weight on the foot. If you rolled your ankle and the pain is primarily on the inside, it’s worth getting evaluated, particularly because of the association with fractures that may not be obvious from the outside.
Tarsal Tunnel Syndrome
If your inner ankle pain comes with tingling, numbness, or a burning sensation that radiates into the sole of your foot, the tibial nerve may be compressed as it passes through the tarsal tunnel behind the medial malleolus. Some people describe a feeling of walking on pebbles or sand. The symptoms often start out intermittent, flaring after long periods of standing or walking, then fading with rest. In long-standing cases, the numbness and tingling can become constant as the nerve progressively degenerates.
Tarsal tunnel syndrome can be tricky to diagnose because there’s no single definitive test. Diagnosis typically involves a combination of your symptom pattern, a physical exam (tapping over the tarsal tunnel to see if it reproduces tingling into your foot), and ruling out other causes. Nerve conduction studies can help confirm the diagnosis in uncertain cases. Treatment usually starts with reducing the compression through orthotics, footwear changes, or bracing, and may progress to a procedure to release the tunnel if symptoms persist.
Stress Fractures of the Medial Malleolus
A stress fracture in the inner ankle bone causes gradually increasing pain and swelling over the medial malleolus, typically in runners, basketball players, or anyone who has recently ramped up high-impact activity. Unlike an acute fracture, there’s no single traumatic event. The pain worsens with weight-bearing and impact, and you’ll usually have a very specific tender spot when you press directly on the bone.
Standard X-rays miss these fractures more than half the time. In one review of patients with confirmed medial malleolus stress fractures, only 45% had a positive X-ray. Bone scans and CT scans are more reliable for detection. If your inner ankle pain is pinpoint, gets worse with activity, and has been building over days to weeks, a stress fracture should be on the radar, especially if initial X-rays come back normal.
Overpronation and Flat Feet
Sometimes inner ankle pain isn’t caused by a single injury or a specific diagnosis but by the cumulative effect of how your foot moves. Overpronation, where your foot rolls inward excessively with each step, flattens your arch and places chronic strain on the muscles, tendons, and ligaments on the medial side. If you already have flat feet, you’re more likely to develop overpronation over time.
This mechanical pattern is often the underlying driver behind posterior tibial tendon problems, and it can also contribute to tarsal tunnel compression and general medial ankle soreness. Addressing it with motion-control shoes, arch-supporting insoles, or custom orthotics can relieve symptoms and reduce the risk of progression. Strengthening exercises for the foot and lower leg muscles help as well, particularly single-leg balance work and calf raises performed slowly.
Signs That Need Prompt Evaluation
Most inner ankle pain improves with rest, ice, and supportive footwear within a few days to a couple of weeks. Certain signs, however, suggest something more serious is going on. If you can’t bear weight on the foot at all, or if you can’t take four steps without significant pain, imaging is warranted. Point tenderness directly over the medial malleolus bone (not just the soft tissue around it) raises concern for a fracture. Rapid swelling after an injury, visible deformity, or numbness in the foot also warrant prompt attention. Pain that has been steadily worsening over several weeks despite rest, or an arch that appears to be flattening on one side, suggests a tendon problem that benefits from early intervention before the foot’s structure changes.