Electroneuromyography (ENMG)

ENMG studies diseases of the peripheral nervous system and muscles. A common reason for an ENMG is a functional deficit due to local peripheral nerve damage that causes muscle weakness, somatosensory disorders or pain. Examples of these include back pain radiating down the leg (sciatica) and compression of the median nerve (carpal tunnel syndrome).

Other reasons for the examination include various myopathies (muscle diseases), generalised polyneuropathy, and diseases involving a neuromuscular junction or ion channel.

The examination usually consists of two parts: electroneurography and needle EMG. To examine nerve function, small electrodes are attached to the surface of the skin at the site of a muscle or sensory nerve. The nerve is then stimulated with small electric shocks. The test equipment measures the passage of the stimulus along the nerve.

To examine muscle function, the physician inserts a thin needle (size similar to an acupuncture needle) in the muscle being examined. The needle is used to record electrical activity in the muscle and related disturbances caused by diseases of the nervous system and muscles. 

Patient instructions for an ENMG examination (Hoito-ohjeet.fi)