What is the pathogenesis of deep peroneal nerve entrapment?

Updated: Oct 15, 2019
  • Author: Minoo Hadjari Hollis, MD; Chief Editor: Thomas M DeBerardino, MD  more...
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Answer

Deep peroneal nerve entrapment is most commonly due to compression and repetitive mechanical irritation of the nerve at the ankle beneath the extensor retinaculum. Entrapment of the deep peroneal nerve in this location has also been called the anterior tarsal tunnel syndrome.

The anterior tarsal tunnel contains four tendons, one artery, one vein, and the deep peroneal nerve. Typically, the nerve is trapped beneath the superior edge of the retinaculum. Here, it is compressed by the crossing extensor hallucis longus tendon and under the extensor hallucis brevis, as well as directly over osteophytes, exostosis, or bony prominences of the talotibial, talonavicular, naviculocuneiform, or cuneiform metatarsal joints. An os intermetatarseum between the first and second metatarsal bases has also been associated with symptoms.

Space-occupying lesions (eg, ganglia) also contribute to symptoms in this tight canal. Repeated dorsiflexion and plantarflexion of the ankle contributes to this mechanical condition by pinching the nerve in this tight space, and inversion trauma has been shown to lower the motor conduction velocity of the deep peroneal nerve.

Postural causes, such as wearing high-heeled shoes (in which the nerve is stretched over the midfoot joint) and sitting repeatedly or for prolonged periods on the plantarflexed feet (as is done by Muslims performing salat, or namaz) are other commonly seen etiologies. Other etiologies include anomalies of the extensor hallucis brevis distal to the retinaculum.

Deep peroneal nerve entrapment, however, can occur anywhere along the nerve’s course (eg, just distal to the neck of the fibula, anterior to the ankle joint, or distal to the inferior extensor retinaculum), though such entrapment is not considered anterior tarsal tunnel syndrome. Common causes of proximal entrapment of the deep peroneal nerve include space-occupying lesions about the proximal fibula, surgical procedures about the lateral knee (eg, proximal tibial osteotomy), and chronic anterior exertional compartment syndrome seen in athletes.


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