Deep peroneal nerve entrapment, also known as anterior tarsal tunnel syndrome, primarily manifests as nerve-type pain and sensory disturbances in the foot, often leading to discomfort and functional limitations.
Understanding Deep Peroneal Nerve Entrapment
The deep peroneal nerve is a branch of the common peroneal nerve that runs down the front of the leg and into the top of the foot. It provides sensation to the web space between the first and second toes and controls muscles that help lift the foot and toes. When this nerve becomes compressed or entrapped, typically near the ankle or on the top of the foot, it can lead to a variety of symptoms.
Key Signs and Symptoms
The signs and symptoms of deep peroneal nerve entrapment can vary in intensity and presentation but commonly involve pain and altered sensation.
Pain Characteristics
A hallmark symptom of deep peroneal nerve entrapment is nerve-type pain in the foot. This pain is often described as:
- Location-specific: Typically felt over the top of the foot, most notably between the first and second metatarsal bones.
- Spontaneous and Sporadic: The pain can occur suddenly and intermittently, without a clear trigger.
- Disproportionate: Patients often describe this pain as not proportional to the objective clinical findings, meaning the intensity of discomfort can be high even if visible signs of injury are minimal.
- Burning or Aching: Beyond sharp pain, some individuals may experience a burning sensation or a deep ache.
Sensory Changes
Compression of the deep peroneal nerve can also lead to changes in sensation along its distribution:
- Numbness: A loss of feeling, particularly in the web space between the first and second toes.
- Tingling (Paresthesia): A "pins and needles" sensation.
- Burning Sensation: A feeling of heat or burning, sometimes described as nerve irritation.
Motor Weakness (Less Common but Possible)
While less common in mild cases, prolonged or severe entrapment can affect the motor function of the nerve, potentially leading to:
- Weakness in Toe Extension: Difficulty lifting or extending the big toe.
- Mild Foot Drop: In very severe or chronic cases, there might be a subtle weakness in ankle dorsiflexion, leading to a slight drag of the foot.
Aggravating Factors
Symptoms may be exacerbated by:
- Activity: Prolonged walking, running, or standing can worsen pain.
- Tight Footwear: Shoes that are too tight or restrictive over the top of the foot can increase compression on the nerve.
- Repetitive Motion: Activities that involve repeated ankle dorsiflexion or foot pronation.
Common Deep Peroneal Nerve Entrapment Symptoms
| Symptom | Description | Typical Location |
|---|---|---|
| Pain | Nerve-type, spontaneous, sporadic, often disproportionate to findings. | Top of the foot, especially between 1st and 2nd toes |
| Numbness | Loss of sensation. | Web space between 1st and 2nd toes |
| Tingling | "Pins and needles" sensation. | Web space between 1st and 2nd toes |
| Burning Sensation | Feeling of heat or burning. | Top of the foot or specific web space |
| Motor Weakness | Difficulty extending the big toe (dorsiflexion). | Affects toe and foot movement |
Diagnosis and Clinical Findings
Diagnosing deep peroneal nerve entrapment often involves a physical examination, assessing the range of motion, muscle strength, and sensation in the foot. Imaging studies like MRI or nerve conduction studies may be used to confirm the diagnosis or rule out other conditions. The "disproportionate" nature of the pain compared to clinical findings is a key characteristic that can guide diagnosis.
Understanding these signs and symptoms is crucial for early recognition and appropriate management of deep peroneal nerve entrapment, helping to alleviate discomfort and prevent further nerve damage. For further information on peripheral nerve conditions, consult resources like the Mayo Clinic or National Institute of Neurological Disorders and Stroke (NINDS).
