What is Baxter's Neuritis of the Heel?

The most common cause of heel pain in adults is plantar fasciitis, but up to 20% of cases of chronic heel pain could be a nerve entrapment called Baxter’s neuritis. The two often get confused and can lead to a poorer outcome if the diagnosis is not made correctly early on. Baxter’s nerve or technically, the first branch of the lateral plantar nerve supplies nerve sensation to the heel area and also innervates several muscles on the bottom of the foot. After the nerve passes into the foot from the ankle area it changes from being vertical to run in a horizontal direction passing between two muscles. It can become entrapped or pinched in that area if the muscles become enlarged. The nerve could also be compressed by a bony heel spur or even the swelling of a plantar fasciitis might irritate the nerve. The actual cause of the entrapment is not totally clear but could be due to trauma to the muscle or an enlargement of the muscles from overuse.

The location of the pain of a Baxter’s neuritis and plantar fasciitis are typically in about the same place so it can be hard for a clinician to tell the differences. However, there are some things that indicate one over the other. Plantar fasciitis is typically more painful first thing in the morning for those first few steps whereas Baxter’s neuritis is not typically worse then and gets worse later in the day. The maximum area of pain for plantar fasciitis is under the heel whereas for Baxter’s neuritis it is under the heel and maybe a bit up the side of the heel area as well. As a nerve is involved in Baxter’s there can be some nerve like symptoms such as shooting pains, numbness or pins and needles like sensations. A clinician may be able to do some tests that stretch the nerve and produce the symptoms. Imaging is a more definitive way to differentiate the two. An ultrasound or MRI will show the inflammation of a plantar fasciitis to confirm that diagnosis. If there is no inflammation of the plantar fascia, then it is likely to be Baxter’s neuritis. Sometimes an MRI may be able to show a swelling in the nerve where the entrapment is. As well as ruling out plantar fasciitis, there are other heel pain conditions that the symptoms could be due to and these need to be ruled out. These can include an atrophy of the plantar fat pad, a stress fracture of the heel bone and a rheumatological condition that can cause heel pain.

The treatment of Baxter’s nerve entrapment can involve a number of similar things that are used to treat plantar fasciitis. Shock absorbing heel cups and foot orthoses are often used to support the area. Barefoot walking can be painful, so that is best avoided. Anti-inflammatory drugs can be used and cortisone injections may be needed. For those cases that are resistant to this treatment, a surgical resection of the nerve may be needed.