Ultrasonography of peripheral nerves

Abstract

Over the last decade, neuromuscular ultrasonography has emerged as a useful tool for the diagnosis of peripheral nerve disorders. This article reviews sonographic findings of normal nerves, including key quantitative ultrasound measurements that are helpful in the evaluation of focal and possibly generalized peripheral neuropathies. It also discusses several recent articles outlining the evidence base for the use of this technology, as well as new findings in compressive, traumatic, and generalized neuropathies. Ultrasonography is well suited for use in electrodiagnostic laboratories, where physicians, experienced in both the clinical evaluation of patients and the application of hands-on technology, can integrate findings from the patient's history, physical examination, electrophysiological studies, and imaging for diagnosis and management.

Figure 1

On the left is a cross-sectional view of the median nerve (arrow) at the distal wrist crease in a healthy volunteer. The cross-sectional area of the nerve is 9 mm² and there is normal nerve echogenicity. On the right is the same view from an individual with carpal tunnel syndrome. The nerve is 19 mm² and very hypoechoic. T = flexor tendons and C = carpal bones.