Peripheral nerve ultrasound uses high-resolution sonography to image the morphology of peripheral nerves, detecting nerve entrapment, traumatic injury, tumors, and inflammatory neuropathy. The real-time, dynamic capabilities of ultrasound complement electrodiagnostic studies (EMG/NCS) by providing structural correlates to functional abnormalities.
Sonographers assess nerve cross-sectional area (CSA), echogenicity, and fascicular pattern at multiple levels along the nerve course. Carpal tunnel syndrome is the most common application — an enlarged median nerve CSA at the wrist inlet is a diagnostic criterion. Other studied nerves include the ulnar nerve at the elbow, the common peroneal nerve at the fibular neck, and the femoral nerve. Nerve sheath tumors (schwannomas, neurofibromas) and post-traumatic neuromas are also imaged.
Nerve ultrasound is a specialized application typically performed by sonographers with RDMS or MSK credentials and additional training in neuromuscular sonography. It is offered at academic medical centers, neurology departments, and electrodiagnostic labs. Demand is growing as ultrasound guidance for nerve blocks, carpal tunnel injections, and perineural hydrodissection becomes standard practice.