Dynamic Ulnar Nerve Dislocation
 

Author: Steven Greenberg, MD, MS
Affiliation: CMC Sports Medicine
Co Author(s): David Price, MD
Senior Editor: Wesley Troyer, DO
Editor: Laura Mattson, DO

Clinical Vignette: 40 yo Male describing shock-like sensation, numbness, pain and weakness in the left forearm with preacher curls. Numbness extends into the medial hand. Further evaluation found symptoms recurred with hyperflexion or hyperextension.

Type of Probe Used: LA3-16AI Hockey-Stick transducer Positioned transverse and posterior on the right proximal upper extremity superior to the medial epicondyle.



Short axis view of the ulnar nerve at the level of the medial epicondyle, with elbow positioned in approximately 70-90 degrees of flexion. This image demonstrates the ulnar nerve (yellow), medial epicondyle (blue) and medial head of the triceps (red) in its usual configuration, with the nerve within the ulnar groove. In this region, there was focal enlargement of the ulnar nerve, with maximal cross sectional area of 15mm2 (normal <10mm2).


Short axis view of the ulnar nerve at the level of the medial epicondyle, with the elbow positioned in maximal flexion. Here the ulnar nerve is seen outside of the ulnar groove (dislocated), anterior to the medial epicondyle.
View Video

During dynamic ultrasound evaluation, the patient's elbow was flexed and the ulnar nerve was seen to dynamically dislocate out of the ulnar groove. With elbow extension, the nerve was seen to spontaneously reduce. During this assessment, the patient's typical symptoms were reproduced. In the attached video, we begin with the patient in a position of maximal elbow flexion, with the nerve already dislocated anterior to the medial epicondyle. With elbow extension, the nerve is then seen to relocate posterior to the medial epicondyle in its normal, anatomic position.

NOTE: For more information, please contact the AMSSM, 4000 W. 114th Street, Suite 100, Leawood, KS 66211 (913) 327-1415.
 

© The American Medical Society for Sports Medicine
4000 W. 114th Street, Suite 100
Leawood, KS 66211
Phone: 913.327.1415


Website created by the computer geek