Numbness in the heel, medically known as paresthesia, is a sensory symptom indicating a disruption in the nervous system’s communication pathway. This sensation, often described as tingling, “pins and needles,” or a loss of feeling, occurs when the nerves relaying sensory information from the heel to the brain are irritated or compressed. The heel receives its sensory input primarily from branches of the tibial nerve, a major nerve running down the leg. Identifying the source of this disruption is the initial step toward finding relief, as the problem can originate near the foot or higher up the kinetic chain.
Localized Nerve Compression in the Foot and Ankle
The most frequent mechanical cause of heel numbness originates at the ankle, specifically within a narrow passageway called the tarsal tunnel. This tunnel is situated along the inside of the ankle, formed by the ankle bones and the flexor retinaculum, a strong band of connective tissue. The posterior tibial nerve and its branches pass through this tight space, making them susceptible to compression.
Compression of the posterior tibial nerve or its branches results in Tarsal Tunnel Syndrome (TTS). This compression can be caused by swelling from an ankle sprain, the presence of a bone spur or ganglion cyst, or structural abnormalities like fallen arches. The pressure disrupts electrical signals, presenting as numbness, tingling, or a burning sensation that often extends to the bottom of the foot and the heel.
A more localized form of entrapment affects the medial calcaneal nerve, a branch of the tibial nerve that provides sensation to the skin over the medial and posterior heel. This nerve can become entrapped between the tight fascia of the abductor hallucis muscle and the calcaneus (heel bone).
Repetitive trauma, excessive foot pronation, or scar tissue from injury can lead to this specific entrapment, causing localized pain and paresthesia in the inner heel area. This condition is sometimes referred to as Baxter’s nerve entrapment and is often misdiagnosed as plantar fasciitis.
Conditions Originating Outside the Foot
Heel numbness may also stem from a problem originating far from the foot, often involving the lower spine or a systemic health condition. A common proximal cause is radiculopathy, which is the compression or irritation of a nerve root as it exits the spinal column in the lower back. The L5 and S1 nerve roots contribute to the sciatic nerve, and compression at these levels can send neurological symptoms down the leg and into the heel.
Compression of the S1 nerve root is often associated with numbness, tingling, or pain that radiates down the back of the leg and into the outer or bottom portion of the foot, including the heel. This is commonly referred to as sciatica, typically caused by a herniated disc or spinal stenosis putting pressure on the nerve root.
Systemic diseases can damage nerves throughout the body, leading to peripheral neuropathy. Diabetes is the most common cause, as chronically high blood sugar levels damage the tiny blood vessels supplying the nerves. This damage typically affects the longest nerves first, leading to symmetrical numbness or tingling that begins in both feet, often involving the heel.
Other Systemic Causes
Other factors contributing to peripheral neuropathy include:
- Nutritional deficiencies, particularly a lack of Vitamin B12, which is necessary for maintaining healthy nerve function.
- Impairment of the protective myelin sheath surrounding the nerves, resulting in symptoms like burning or tingling in the feet.
- Certain medications, such as some chemotherapy drugs, which can damage nerve cells as a side effect.
Immediate Steps and Home Relief Measures
For temporary relief of heel numbness, immediate steps can be taken to alleviate pressure and reduce inflammation. Resting the foot and avoiding aggravating activities, such as prolonged standing or high-impact exercise, is advisable. Changing footwear to options that provide better arch support and cushioning can also reduce pressure on the nerves passing through the ankle.
Applying a cold pack to the ankle or heel area for short periods helps reduce localized swelling, which relieves nerve compression. Gentle stretching of the calf and foot muscles can improve flexibility and decrease tension on the posterior tibial nerve. These measures manage symptoms but do not address the underlying cause.
It is important to recognize “red flag” symptoms that necessitate immediate medical consultation. Sudden and severe onset of numbness, especially if accompanied by rapid weakness in the foot, requires urgent evaluation. The loss of bowel or bladder control alongside numbness is a sign of a severe neurological emergency. If numbness persists, worsens, or is accompanied by increasing pain, professional medical guidance is necessary to prevent long-term nerve damage.
Medical Evaluation and Treatment Approaches
A medical professional begins the diagnostic process using specialized electrodiagnostic tests to assess nerve function. A Nerve Conduction Study (NCS) measures the speed and strength of electrical signals traveling through the nerve, which can pinpoint the exact location and severity of nerve compression. This is often performed in conjunction with an Electromyography (EMG), which involves inserting a fine needle into the foot muscles to evaluate their electrical activity.
Imaging studies, such as X-rays or Magnetic Resonance Imaging (MRI), are utilized to visualize the anatomical structures around the heel, ankle, or spine. X-rays identify bone spurs or fractures, while an MRI provides detailed images of soft tissues, helping to reveal herniated discs or fluid collections that might be compressing a nerve. Blood tests are also performed to check for systemic causes, such as high blood sugar levels indicating diabetes or deficiencies in essential nutrients like Vitamin B12.
Conservative treatment is the initial approach for most cases of heel numbness. This includes prescribing custom orthotics to correct foot alignment and reduce mechanical stress on the tibial nerve. Physical therapy may be recommended to strengthen supporting muscles and improve gait mechanics. Nonsteroidal anti-inflammatory medications (NSAIDs) help manage pain and reduce inflammation contributing to nerve compression.
If conservative methods fail, interventional treatments are considered. Steroid injections can be administered directly into the tarsal tunnel to deliver potent anti-inflammatory medication, offering temporary relief. For confirmed entrapment cases that do not respond to injections, surgical decompression, such as a tarsal tunnel release, may be performed. This procedure involves cutting the tight flexor retinaculum to create more space, relieving pressure on the posterior tibial nerve and allowing it to heal.