Ann Clin Neurophysiol.  2022;24(2):46-52. 10.14253/acn.2022.24.2.46.

A beginner’s guide to peripheral nerve ultrasound

• Seok JI

• KMID: 2535717
• DOI: http://doi.org/10.14253/acn.2022.24.2.46

Abstract

Ultrasonography is currently being developed as a tool for evaluating peripheral neuropathy. It is one of the painless and least-invasive methods of medical diagnostic testing that yields anatomic views of the nerves and their surrounding structures. Here I first describe the equipment settings and technique for nerve ultrasound along with typical sonographic findings for normal nerves. I then address frequently used parameters for nerve measurements that facilitate diagnoses of focal and generalized neuropathies.

Keyword

Ultrasonography; Peripheral nerves; Peripheral nervous system diseases

Figure

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  Fig. 1. The two types of ultrasound transducers specialized for musculoskeletal applications: linear array (A) and hockey stick (B).

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  Fig. 2. Normal sonographic anatomy of the median nerve at different levels. (A) The elbow was flexed to 80-90° with the forearm in full supination in a seated position. (B) Transverse image shows the median nerve (arrow) at the proximal tunnel (at the scaphoid-pisiform level). (C) The median nerve (arrow) lies between the flexor digitorum profundus and the flexor digitorum superficialis at the forearm. (D) The median nerve (arrow) lies close to the brachial artery (open arrowhead) at the distal third of the upper arm. BB, biceps brachii; Br, brachialis; H, humerus; fdp, flexor digitorum profundus; fds, flexor digitorum superficialis; fcr, flexor carpi radialis; S, scaphoid; P, pisiform; u, ulnar nerve; a, ulnar artery

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  Fig. 3. Normal sonographic anatomy of the ulnar nerve at different levels. (A) The elbow was flexed at 90° in a supine position. (B) Transverse image shows the ulnar nerve (arrow) at the proximal tunnel (at the scaphoid-pisiform level). The ulnar artery and nerve run lateral to the pisiform. (C) Transverse image shows the ulnar nerve (arrow) at the medial epicondyle-olecranon level. m, median nerve; a, ulnar artery; S, scaphoid; P, pisiform; O, olecranon; ME, medial epicondyle.

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  Fig. 4. Normal sonographic anatomy of the radial nerve at the spiral groove. (A) The elbow was flexed moderately with the forearm pronated in a seated position. (B) The radial nerve (arrow) lies in close contact with the humerus. t, triceps; br, brachialis; H, humerus.

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  Fig. 5. Normal median nerve. (A) Transverse cross-sectional view of the median nerve (arrow) at the distal wrist crease in a healthy participant. (B) The tracing method performed just inside the hyperechoic rim for measuring the cross-sectional area of the median nerve. fcr, flexor carpi radialis tendon; S, scaphoid; P, pisiform.

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  Fig. 6. Ultrasonographic images of the median nerve with full mobility. (A) At rest, the median nerve (arrow) is the most-superficial structure. (B) The median nerve (arrow) dives deep into the flexor tendon when the fingers and wrist are flexed. T, tendon; fpl, flexor pollicis longus; fcr, flexor carpi radialis.

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