Causes of Inner Ankle Pain
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The Baxter’s Nerve (Inferior Calcaneal Nerve) is a nerve that branches off from a larger nerve of the ankle called the lateral Plantar Nerve that arises from the Tarsal Tunner of the ankle. The purpose of the Baxter’s nerve is to innervate the small muscles of the foot and the undersurface of the heel. Due to the location of the Baxter’s nerve, it makes it more vulnerable to compression by surrounding muscles or external factors such as ill-fitting shoes. When the nerve becomes compressed, it becomes inflamed; leading to a Baxter’s Nerve Entrapment.
The symptoms of Baxter’s Nerve Entrapment include heel pain, especially after activity that is similar in presentation to Plantar Fasciitis. However, while Plantar Fasciitis pain normally improves with gentle activity the symptoms of a Baxter’s Nerve Entrapment normally worsen. Tight-fitting shoes can compress the nerve and cause numbness in the heel of the foot while it is normally hypersensitive to touch the inner aspect of the heel.
Walking on uneven surfaces, ill-fitted custom orthotics and poorly fitted shoes can aggravate the symptoms of a Baxter’s Nerve Entrapment.
It is estimated that 20% of all heel pain is caused by Baxter’s Nerve Entrapment. Baxter’s Nerve Entrapment can be caused by compression from some of the smaller muscles in the foot. A bone spur on the heel can pinch the Inferior Calcaneal Nerve leading to an entrapment while tight-fitting shoes or custom orthotics that are ill-fitting can also cause Baxter’s Nerve Entrapment, another cause includes having flat feet.
While a Baxter’s Nerve Entrapment is often misdiagnosed as Plantar Fasciitis, it can also be caused by Plantar Fasciitis. As the connective tissue of the Plantar Fascia thickens, it can compress the nerve and cause Baxter’s Nerve Entrapment.
A clinical diagnosis of a Baxter’s Nerve Entrapment by a Physical Therapist is possible following a physical examination. One of the key aims of this assessment is for the clinician to differentiate between Plantar Fasciitis and a potential Baxter’s Nerve Entrapment. We would expect morning pain and stiffness with Plantar Fasciitis but not with a Baxter’s Nerve Entrapment while numbness that can be associated with Baxter’s Nerve Entrapment is very rarely present for Plantar Fasciitis.
It is common for a clinician to refer for imaging to assist with their clinical diagnosis. An MRI can show some subtle signs of swelling in the Inferior Calcaneal Nerve that indicates Baxters Neuritis but it is most helpful for ruling our Plantar Fasciitis. An x-ray can rule out a bone spur while an ultrasound is also a useful imaging tool.
As the nerve becomes inflamed we recommend reducing your step count as much as possible and wearing wide-fitting cushioned shoes. A consultation with a Physical Therapist is recommended to identify muscular imbalances that can be addressed with stretches and strengthening exercises.
Taping methods are effective at offloading a Baxter’s Nerve Entrapment while custom insoles are a highly effective form of pain relief.
In some cases, an ultrasound-guided corticosteroid injection is required if a Baxter’s Nerve Entrapment fails to settle with conservative treatment. It is recommended that all injections for this condition are ultrasound guided as the injection site is different to that used for Plantar Fasciitis.
We believe that tightness and thickening of the Plantar Fascia can cause Baxter’s Neuritis so it is important to regularly stretch the Plantar Fasciitis for pain relief.
The soleus muscle sits at the back of the shin bone and it is a key stabiliser of the ankle and foot. If the Soleus muscle becomes tight, it can overload the Plantar Fascia.