Sural Neuropathy – When Nerve Damage Affects the Outer Foot

Tingling, burning, or numbness around the outer ankle or the edge of the foot may be signs of sural neuropathy – a condition involving injury to the sural nerve. This purely sensory nerve is often affected by accidents, surgical procedures, or pressure from the outside. In many cases, imaging techniques such as high-resolution ultrasound help to precisely localize the damage.

What is the sural nerve?

The sural nerve is a sensory nerve that supplies the outer side of the foot and the lateral heel. It is typically formed by the joining of two nerves:

The medial sural cutaneous nerve, originating from the tibial nerve
The lateral sural cutaneous nerve, branching from the common peroneal nerve

The sural nerve then runs superficially along the back of the calf, passes behind the lateral ankle, and continues toward the lateral foot. Because of its superficial course, the nerve is particularly vulnerable to injuries and surgical complications.

Schematic illustration of the left lower leg and foot with the course of the sural nerve added. — The sural nerve runs superficially along the lower leg toward the outer edge of the foot. This image shows its typical course in the left leg.

Symptoms: What do patients notice?

Damage to the sural nerve can cause symptoms such as:

Tingling or burning at the outer edge of the foot or heel
Numbness or altered skin sensation (hypesthesia)
Pain when the affected area is touched, sometimes in the form of a sharp, electrical sensation

Cartoon-style schematic illustration of the left lower leg and foot with marked pain area, indicating possible sural nerve involvement or sural neuropathy. — Sural nerve pain on the outer edge of the left foot – the red area illustrates the typical discomfort zone in sural neuropathy, often described as burning, tingling, or stabbing.

The symptoms often occur after an injury, strain, or procedure – but in some cases, the exact trigger remains unclear.

Common causes

Sural neuropathy can occur after:

Trauma (e.g., ankle sprain, fracture)
Surgical procedures near the lateral ankle, Achilles tendon, or foot
External pressure (e.g., tight footwear or casts)
Scarring or adhesions from wound healing

In rare cases, the nerve may also be compressed by anatomical structures or space-occupying lesions.

Neuroma formation

In some cases, the sural nerve is partially or completely severed during an injury or surgery. At the site of damage, a neuroma may form – a benign overgrowth of nerve fibers due to misguided healing. This can lead to a distinct trigger point, where even light touch provokes intense, shooting pain. Neuromas can occur anywhere along the nerve’s course, including its contributing branches.

Schematic illustration of a thickened nerve with a knot and lightning symbol indicating a painful. — A painful neuroma can form when nerve fibers grow back disorganized after injury. The lightning symbol represents the typical shooting pain.

How is sural neuropathy diagnosed?

Clinical examination

A detailed examination can reveal:

Tenderness or pain when pressing along the nerve path
Localized trigger points
Decreased sensation at the outer foot or heel

A positive Tinel’s sign (a sharp pain when tapping over the nerve) may indicate nerve irritation. However, in cases with partial injury or altered skin condition, these signs may be less clear.

Imaging with high-resolution ultrasound

Because the sural nerve runs close to the skin, ultrasound is particularly well suited for its examination. This non-invasive technique allows real-time visualization of the nerve and its surrounding structures – all without radiation or contrast agents.

Illustration of a high-resolution ultrasound probe for visualizing peripheral nerves. — High-resolution probes can help visualize fine nerve structures in detail.

Ultrasound can help detect:

Nerve swelling or thickening
Scar tissue or adhesions
Entrapment by surrounding tissues
Formation of a neuroma
Reduced nerve mobility or altered elasticity

Even small branches, such as the lateral calcaneal branch, can be visualized with appropriate settings.

Neurophysiological testing

Electrophysiological techniques such as nerve conduction studies (NCS) play a rather limited role in the diagnosis of trauma-related sural neuropathy. Especially in cases of partial nerve injury accompanied by pain symptoms or soft tissue trauma with swelling, these methods often do not provide clearly interpretable results.

Neurophysiological testing may, however, be used for differential diagnostic purposes.

Treatment options

Treatment depends on the location and cause of the structural nerve damage. Options may include:

Protective measures (e.g., avoiding pressure or friction)
Specialized footwear or padding
Physical therapy or desensitization
Ultrasound-guided nerve infiltration
In selected cases, referral to a nerve specialist may be considered for further evaluation and surgical planning

Schematic illustration of a personalized treatment plan with a central symbol surrounded by medical options. — Every treatment plan should be tailored to the symptoms and needs of the individual.

Summary

Sural neuropathy is a rare but often distressing condition affecting the outer foot. It frequently occurs after injuries or operations and may cause burning, tingling, or pain.

A careful clinical assessment and targeted imaging – especially with high-resolution ultrasound – are essential for diagnosis. They help identify the exact location and extent of nerve damage and assist in determining the next steps in care.

Disclaimer: The information provided on this page is for general informational purposes only and does not constitute medical advice. It is not a substitute for personal consultation, examination, or treatment by a physician or other qualified healthcare professional. No guarantees of healing or cure are made. While we strive for accuracy and completeness, we cannot guarantee that all content is up to date or free from errors, and we accept no liability for any inaccuracies.