Nerve Entrapment in Ankle and Foot: Ultrasound Imaging

Abstract

Peripheral nerve entrapment of the ankle and foot is relatively uncommon and often underdiagnosed because electrophysiologic studies may not contribute to the diagnosis. Anatomy of the peripheral nerves is variable and complex, and along with a comprehensive physical examination, a thorough understanding of the applied anatomy is essential. Several studies have helped identify specific areas in which nerves are commonly compressed. Identified secondary causes of nerve compression include previous trauma, osteophytes, ganglion cysts, edema, accessory muscles, tenosynovitis, vascular lesions, and a primary nerve tumor. Imaging plays a key role in identifying primary and secondary causes of nerve entrapment, specifically ultrasound (US) and magnetic resonance imaging. US is a dynamic imaging modality that is cost effective and offers excellent resolution. Symptoms of nerve entrapment may mimic other common foot and ankle conditions such as plantar fasciitis.

Clinico-radiological review of peripheral entrapment neuropathies – Part 2 Lower limb

“…Other compressive lesions, such as osteophytes, are also detected on MRI [75]. The nerve is detected on the US and can aid in percutaneous injection therapy [76]. Additionally, US may also be used to detect muscle atrophy.…”

“…On the other hand, MRI may help in delineating the extent of the spaceoccupying lesion (Fig. 16) and also show signal alterations in the nerve as well as denervation changes [2,76].…”

“…Incidental interdigital neuromas are detected in about 33 % of asymptomatic individuals, and hence, treatment is based on clinical symptoms [88]. US is equally effective in diagnosing the condition with the added advantage of identifying compression-induced pain, which is the characteristic of the lesion [76]. Both US and MRI are effective in differentiating the neuroma from associated intermetatarsal bursitis [91,92].…”