Tarsal tunnel syndrome is compression of the posterior tibial nerve as it passes through a narrow anatomical tunnel on the inside of the ankle, producing burning, tingling, or numbness that can radiate into the sole of the foot. It is often compared to carpal tunnel syndrome in the wrist, since the underlying mechanism — nerve compression within a confined anatomical space — is very similar.
The tarsal tunnel is a narrow passage on the inside of the ankle, bordered by bone on one side and a fibrous band of tissue (the flexor retinaculum) on the other, through which the posterior tibial nerve and several tendons pass on their way into the foot. Because the tunnel is a fixed, confined space, anything that reduces the room available within it — swelling, a structural growth, or altered foot mechanics changing the angle at which structures pass through — increases pressure directly on the nerve. Sustained compression of this kind gradually impairs the nerve’s normal function, producing the characteristic burning, tingling, and numbness of tarsal tunnel syndrome.
Tarsal tunnel syndrome can result from anything that narrows the tunnel or increases pressure on the nerve within it — a space-occupying lesion such as a cyst or varicose vein, swelling from a previous ankle injury, flat feet altering the mechanics and space within the tunnel, or, in some cases, no clearly identifiable cause at all. Systemic conditions affecting nerve health, such as diabetes, can also make the nerve more vulnerable to compression, and are worth specifically mentioning at assessment if relevant.
Diagnosis combines characteristic symptoms with specific clinical tests. Tinel’s sign — tapping directly over the nerve at the inside of the ankle to see whether it reproduces the tingling sensation in the sole of the foot — is a key diagnostic finding. Phalen’s test, and its ankle equivalent, add further clinical information by provoking symptoms through sustained positioning. Nerve conduction studies and, where a structural cause is suspected, MRI or ultrasound imaging can help confirm the diagnosis and identify any underlying cause requiring specific treatment, such as a compressive cyst.
Surgery is considered when symptoms persist despite non-surgical management, or where imaging identifies a specific structural cause — such as a cyst — directly compressing the nerve. Surgical release of the flexor retinaculum decompresses the nerve, with the specific approach guided by whether a structural cause has been identified, discussed individually at consultation.
Burning, tingling, or numbness on the inside of the ankle that often radiates into the sole of the foot, typically worse with standing or walking and sometimes noticeable at night.
Diagnosis combines the characteristic pattern of symptoms with specific clinical tests, including Tinel’s sign, and is often supported by nerve conduction studies or imaging where a specific structural cause is suspected.
Book an assessment with Mr Schneider for an accurate diagnosis and a treatment plan matched to the underlying cause.