The medial calcaneal nerve is a branch of the tibial nerve, which is a major nerve supplying most of the muscles and skin of the back of the leg. The medial calcaneal nerve arises from the main nerve of the inner side of the ankle, perforates the laciniate ligament, travels downwards passing below the bony projection on the inner side of the ankle, and supplies the skin over the medial aspect of the heel.
A nerve can become entrapped on its way from the organ that it supplies to the central nervous system as it passes in between the bones and their associated ligaments or through the muscles. Usually in case of entrapment, the nerve gets compressed between a static and a mobile surface. As the body moves, the nerve is subjected to repeated sliding or friction, leading to compression and trauma. This trauma may damage the outer sheath of the nerve that helps with signal transmission and cause other structural alterations that eventually lead to pain and loss of function.
The medial calcaneal nerve may become entrapped between the tight fascia at the origin of the abductor hallucis muscle and the heel bone (calcaneus).
An excessive pronation of the foot may lead to medial calcaneal nerve entrapment. This can occur as a postoperative complication during the release of the lateral plantar nerve branch.
There is pain and paresthesia (burning or tingling) in the areas supplied by the nerve, that is below the inner bony projection of the ankle and under the heel. The pain usually initiates on the inside of the heel and travels towards the center. Any activity may further aggravate the pain.
When the medial calcaneal nerve is trapped the Tinel’s sign is positive. This test is performed by lightly tapping the skin over the nerve, which leads to tingling in the area supplied by the nerve.
Medial calcaneal nerve entrapment should not be confused with other causes of heel pain, such as plantar fasciitis and tarsal tunnel syndrome. Accurate diagnosis is important to achieve the desired results.
The first line of treatment includes rest and supportive therapies. Avoid activities that lead to pain; immobilization may also help. Use cold compresses and anti-inflammatory painkillers to reduce the symptoms. Massage or ultrasound therapy is also useful.
If rest and conservative treatment fail to eradicate the symptoms, surgical decompression of the nerve may be required. Surgical treatment usually produces good results.