The deep peroneal nerve is one of two main branches of the common peroneal nerve in the lower leg, and it controls the muscles that lift your foot and toes upward while also providing sensation to a small patch of skin between your first and second toes. When this nerve is damaged or compressed, the consequences can range from subtle numbness on the top of the foot to a full-blown foot drop that makes walking difficult. Despite its relatively narrow territory, the deep peroneal nerve is a remarkably common source of trouble in orthopedic and neurological practice, partly because of where it sits and how vulnerable it is along its path.
Where the Nerve Runs and What It Controls
The deep peroneal nerve branches off from the common peroneal nerve near the outside of the knee, then dives forward through the muscles of the front of the leg. In the lower third of the leg, it sits just on top of the anterior tibial artery, sandwiched between the tibialis anterior muscle (the one that pulls your foot up) and the extensor hallucis longus (the muscle that lifts your big toe). As it approaches the ankle, the nerve typically crosses under the extensor hallucis longus tendon and enters the gap between that tendon and the tendons that extend the smaller toes, roughly a centimeter above the ankle joint line.1PubMed. The deep peroneal nerve in the foot and ankle: an anatomic study
Along this course, the nerve fires the muscles responsible for dorsiflexion, the motion of pulling your foot and toes toward your shin. Without it, you cannot actively lift the front of your foot off the ground. That single function has outsized importance for walking: during the swing phase of each step, your foot needs to clear the ground, and the deep peroneal nerve is the wire that makes that happen.
Once the nerve passes under the extensor retinaculum (a band of tissue that holds the tendons down at the front of the ankle), it splits into two terminal branches. The lateral branch dives into the extensor digitorum brevis, a small muscle on the top of the foot that helps extend the toes. The medial branch continues forward across the top of the foot, traveling close to the first tarsometatarsal joint, and eventually supplies sensation to the web space between the big toe and the second toe.2PubMed. The deep peroneal nerve in the foot and ankle: an anatomic study That small sensory patch is the nerve’s only skin territory, which is why damage higher up in the leg tends to show up mostly as muscle weakness rather than widespread numbness.
Foot Drop and the Deep Peroneal Nerve
The most dramatic consequence of deep peroneal nerve injury is foot drop, the inability to lift the foot during walking. People with foot drop develop a characteristic high-stepping gait, swinging the leg outward or hiking the hip to keep the toes from dragging. Injury to the common peroneal nerve, which feeds both the deep and superficial branches, is the most frequent nerve injury in the lower extremity and disrupts motor control to the ankle dorsiflexors, toe extensors, and foot evertors.3PubMed Central. Gait Improvements After Peroneal or Tibial Nerve Transfer in Patients with Foot Drop: A Retrospective Study When only the deep branch is affected, you lose dorsiflexion and toe extension but keep the ability to evert (turn outward) the foot, because eversion is supplied by the superficial peroneal nerve. That distinction helps clinicians figure out exactly where the damage is.
Common causes of deep peroneal nerve injury include fractures near the knee or ankle, compression from tight casts or boots, habitual leg crossing, prolonged squatting, and surgical complications. One less obvious cause is anterior compartment syndrome, where swelling inside the tight muscle compartment of the front of the leg squeezes the nerve. Even in cases without obvious trauma, compartment pressure can rise enough to impair nerve conduction significantly. In one reported case of spontaneous anterior compartment syndrome, nerve conduction testing showed the signal through the deep peroneal nerve had slowed dramatically and the muscle response had dropped to a fraction of normal.4PubMed. Spontaneous non-traumatic anterior compartment syndrome with peroneal neuropathy and favorable outcome
Anterior Tarsal Tunnel Syndrome
While most people have heard of carpal tunnel syndrome in the wrist, fewer know that a similar compression problem can affect the deep peroneal nerve at the ankle. Anterior tarsal tunnel syndrome occurs when the nerve gets pinched as it passes under the inferior extensor retinaculum on the front of the ankle. The “tunnel” has the retinaculum as its roof and the bones of the foot (talus and navicular) as its floor, with four tendons, an artery, a vein, and the nerve all crowded inside.5Archives of Physical Medicine and Rehabilitation. Anterior tarsal tunnel syndrome: report of two cases
People with this condition typically report pain or odd sensations on the top of the foot, often worse at night. Depending on which branch is compressed, they may notice numbness in the web space between the first and second toes, weakness or wasting of the extensor digitorum brevis muscle on top of the foot, or both.6PubMed. The anterior tarsal tunnel syndrome Tight shoes, high-heeled footwear, bone spurs from arthritis, and ganglion cysts are common culprits. In partial forms of the syndrome, only the motor or only the sensory branch gets compressed, which can make diagnosis tricky because the presentation does not match the full textbook picture.
Treatment often starts with removing the source of compression: loosening shoe lacing, changing footwear, or using padding over the dorsum of the foot. When conservative measures fail, surgical release of the retinaculum can relieve the pressure. Because the condition is relatively rare and sometimes confused with other causes of foot pain, it tends to be underdiagnosed.
An Anatomical Variant That Matters Clinically
Roughly one in five people has an extra nerve branch called the accessory deep peroneal nerve. A meta-analysis pooling data from over 6,000 lower limbs found the accessory branch in about 19% of cases, though the number varies depending on whether cadaveric dissection or electrical testing was used.7Clinical Neurology and Neurosurgery. Prevalence of the accessory deep peroneal nerve: A cadaveric study and meta-analysis Electrodiagnostic studies in clinical populations have found rates between about 12% and 15%.8PubMed Central. Prevalence of accessory deep peroneal nerve in referred patients to an electrodiagnostic medicine clinic9PubMed Central. Prevalence of Accessory Deep Peroneal Nerve in Sample of Bosnia and Herzegovina Subjects: an Electrophysiological Study The variant seems equally common in men and women, and when it is present, it is more often found on one side than both.
This matters because the accessory branch takes a detour behind the outer ankle bone (the lateral malleolus) before reaching the extensor digitorum brevis muscle. In about four out of five people who have it, the accessory nerve supplies some or all of the motor input to that muscle.10Clinical Neurology and Neurosurgery. Prevalence of the accessory deep peroneal nerve: A cadaveric study and meta-analysis If a clinician is testing the deep peroneal nerve by stimulating it at the ankle and recording from the extensor digitorum brevis, a person with this variant can produce confusing results: the muscle response to stimulation below the ankle may be unexpectedly small, because part of the nerve supply arrives through a different route. Recognizing the variant avoids misdiagnosing a healthy nerve as damaged.
How the Nerve Is Tested
Electrodiagnostic testing, primarily nerve conduction studies, is the standard method for confirming deep peroneal nerve problems. The test involves delivering a small electrical stimulus to the nerve at a specific point and recording the muscle response it produces. For the deep peroneal nerve, the standard recording site is the extensor digitorum brevis muscle on the top of the foot. The stimulation point is typically about 8 centimeters above that muscle, roughly a centimeter to the outside of the tibialis anterior tendon, between the tendons that extend the big toe and the smaller toes.11Annals of Rehabilitation Medicine. Optimal Stimulation Site for Deep Peroneal Motor Nerve Conduction Study Around the Ankle: Cadaveric Study
The clinician looks at two main measurements: how long the signal takes to travel from the stimulation point to the muscle (the distal latency) and how large the muscle’s electrical response is (the amplitude). A prolonged latency suggests slowed conduction, often from compression or demyelination. A reduced amplitude suggests fewer nerve fibers are getting the signal through, which may indicate more severe damage. An evidence-based review of electrodiagnostic techniques supports their use in patients with suspected peroneal neuropathy, though the review noted that the overall quality of the available research was moderate.12PubMed. Practice parameter: utility of electrodiagnostic techniques in evaluating patients with suspected peroneal neuropathy: an evidence-based review
In cases where standard testing at the ankle produces a weak or absent response, and the accessory deep peroneal nerve variant is suspected, the examiner can stimulate behind the lateral malleolus to check whether an alternative nerve pathway is supplying the muscle. Without that step, a normal variant could be mistaken for nerve disease.
Surgical Risks to the Nerve
Because the deep peroneal nerve runs across the front of the ankle and top of the foot, it sits in the path of several common surgical procedures. Anterior ankle arthroscopy, for instance, requires creating portals (small incisions) on the front of the ankle, and the nerve can be nicked, stretched, or caught up in scar tissue. In one retrospective review of arthroscopy cases, deep peroneal nerve injuries occurred in about 3% of procedures, with the injuries ranging from temporary entrapment in postoperative adhesions to neuroma formation to more significant axonal damage.13Journal of the Foot and Ankle. Peroneal nerve injuries during anterior ankle arthroscopy
The nerve is also at risk during surgery for Lisfranc (midfoot) injuries, particularly when hardware placed during the initial repair needs to be removed later. One study found that deep peroneal nerve injury after hardware removal for Lisfranc injuries was more common than during the original surgery. Among patients who had nerve injury from the initial fixation, the rate of injury following hardware removal climbed to 23%, though for patients whose nerves were intact after the first surgery, the rate of new injury at hardware removal was closer to 15%. About seven in ten of those nerve injuries persisted at more than a year of follow-up.14PubMed. Deep Peroneal Nerve Injury Following Hardware Removal for Lisfranc Joint Injury These numbers are worth knowing if you are weighing whether to have midfoot hardware removed: the nerve injury risk is real, though most affected patients still reported being at least partially satisfied with their outcomes.
Nerve Blocks and Pain Management
The deep peroneal nerve is one of five nerves that get blocked when performing a complete ankle block for surgery or pain control. Blocking it numbs the web space between the first and second toes and affects motor control of the dorsiflexors. Traditionally, clinicians locate the nerve using surface landmarks, feeling for the pulse of the anterior tibial artery and injecting nearby. Ultrasound guidance has become popular for nerve blocks throughout the body, but for the deep peroneal nerve at the ankle, one randomized study found that ultrasound sped up the onset of the block without improving its overall success rate compared to the landmark technique.15Regional Anesthesia & Pain Medicine. Ultrasound Does Not Improve the Success Rate of a Deep Peroneal Nerve Block at the Ankle
Diagnostic nerve blocks have a separate and growing role. For patients with chronic foot pain, particularly from midfoot arthritis, a targeted injection around the deep peroneal nerve can help determine whether the nerve itself is a significant pain generator. In a retrospective review of ultrasound-guided diagnostic blocks, pain relief was reported in the majority of cases, and among patients who went on to surgical neurectomy (cutting the nerve), most experienced lasting improvement.16PubMed. Ultrasound-guided diagnostic deep peroneal nerve blocks prior to potential neurectomy: a retrospective review The review also highlighted that the nerve’s position relative to the artery is not as predictable as anatomy textbooks suggest: while it was most often lateral to the artery, it was found in several other positions, reinforcing why image guidance is helpful when targeting the nerve higher up in the leg.
Rehabilitation and Electrical Stimulation for Foot Drop
When foot drop results from deep peroneal nerve injury, the first line of treatment is often an ankle-foot orthosis, a brace that holds the foot in a neutral or slightly lifted position so the toes clear the ground during walking. These work well mechanically, but they can be bulky and uncomfortable, and they do not actively engage the muscles.
Functional electrical stimulation (FES) offers an alternative. A small device sends an electrical signal to the deep peroneal nerve or the tibialis anterior muscle during the swing phase of gait, producing a contraction that lifts the foot at the right moment. A large randomized trial comparing FES applied to the peroneal nerve against a standard ankle-foot orthosis in people with chronic foot drop after stroke found that the two approaches produced equivalent improvements in walking speed and quality of life.17PubMed. The effects of peroneal nerve functional electrical stimulation versus ankle-foot orthosis in patients with chronic stroke: a randomized controlled trial Some patients prefer FES because it feels more natural and allows greater ankle mobility during daily activities.
Implantable microstimulators have also been tested. In a case study, a small implanted device stimulating the deep peroneal nerve and tibialis anterior produced enough foot lift to match toe clearance on the patient’s unaffected side.18PubMed. Functional electrical stimulation using microstimulators to correct foot drop: a case study While implantable technology is not yet routine, it points toward a future where stimulators could sit inside the body and activate automatically during walking without external electrodes or cuffs.
When the Nerve Does Not Recover
If the deep peroneal nerve has been severely damaged and does not regenerate on its own, more involved surgical options come into play. Nerve decompression, which surgically opens the tissue around a compressed nerve, can help in cases where the nerve is intact but squeezed. For common peroneal nerve decompression, research has identified factors associated with worse sensory outcomes: a higher body mass index and a delay of more than about 500 days between injury and surgery were both linked to lower odds of regaining normal sensation.19PubMed Central. Outcomes of Common Peroneal Nerve Decompression The takeaway is that earlier intervention tends to produce better results, though motor recovery was less predictable and the study could not identify clear predictors for it.
Tendon transfers represent a salvage option when nerve recovery is not expected. In this procedure, a functioning tendon (typically the posterior tibial tendon, which is powered by a different nerve) is rerouted to do the job of the paralyzed dorsiflexors. The trade-off is that the transferred tendon cannot replicate perfectly normal motion, and rehabilitation is lengthy, but it can eliminate the need for a permanent brace. Because outcomes from primary nerve repair remain uncertain, tendon transfers often end up as the definitive treatment for long-standing foot drop.20Thieme Connect / Indian Journal of Plastic Surgery. Tendon Transfers in Foot Drop
The Nerve in Diabetic Neuropathy
Diabetes adds another layer of vulnerability. Chronically elevated blood sugar damages small blood vessels throughout the body, including those that supply peripheral nerves. When a nerve already suffering from diabetic damage passes through a tight anatomical space, the combination of metabolic injury and mechanical compression can accelerate the loss of function. Surgical decompression at known entrapment sites in diabetic limbs is thought to work by relieving pressure on nerves whose blood supply and internal transport mechanisms are already compromised, allowing partial recovery of nerve fiber health and signal transmission.21World Neurosurgery. Surgical Nerve Decompression at Lower Extremity for Diabetic Neuropathy: A Systematic Review and Meta-Analysis of Time-Dependent Pain, Sensory Recovery, Amputation, Ulcer Recurrence, and Balance
For patients with diabetic neuropathy, protecting the deep peroneal nerve is not just about maintaining toe-lifting strength. Loss of sensation on the top of the foot, combined with the broader sensory deficits of diabetic neuropathy, increases the risk of unnoticed injuries and ulcers. Restoring even partial sensation through decompression can have practical value beyond what the nerve’s small sensory territory might suggest, because every bit of protective feeling in the foot helps people avoid wounds that can spiral into serious complications.