Focal Nerve Entrapment

Focal Nerve Entrapment or Nerve Compression Syndrome (also known as compression neuropathy) is a medical condition caused by direct pressure on a nerve. It is known colloquially as a trapped nerve. The symptoms affect just one particular part of the body, depending on which nerve is affected.


Symptoms include tingling, numbness, and/ or a burning sensation in the area of the body affected by the corresponding nerve. These experiences may occur directly following insult or may occur several hours or even days afterwards. A nerve may be compressed by prolonged or repeated external force, such as sitting with one's arm over the back of a chair (radial nerve), frequently resting one's elbows on a table (ulnar nerve), or an ill-fitting cast or brace on the leg (peroneal nerve). Part of the patient's body can cause the compression and the term entrapment neuropathy is used particularly in this situation. The offending structure may be a well-defined lesion such as a tumour (for example a lipoma, neurofibroma or metastasis), a ganglion cyst or a haematoma. Alternatively, there may be expansion of the tissues around a nerve in a space where there is little room for this to occur, as is often the case in carpal tunnel syndrome. This may be due to weight gain or peripheral oedema (especially in pregnancy), or to a specific condition such as acromegaly, hypothyroidism or scleroderma and psoriasis. Some conditions cause nerves to be particularly susceptible to compression. These include diabetes, in which the blood supply to the nerves is already compromised, rendering the nerve more sensitive to minor degrees of compression.


A focal nerve entrapment can usually be diagnosed confidently on the basis of the symptoms and signs alone. However, Nerve Conduction Studies (NCS) are helpful in confirming the diagnosis, quantifying the severity, and ruling out involvement of other nerves (suggesting a mononeuritis multiplex or polyneuropathy). A scan is not usually necessary, but may be helpful if a tumour or other local compressive lesion is suspected.



If you or someone you know suffers or suspects they may have focal nerve entrapment and are looking for a specialist neurologist, please feel free to contact Synapse Neurology for a consultation.