Presentation
Right-hand 4th and 5th fingers weakness for last few days. No trauma.
Patient Data





There is a small extra structure superficial to the ulnar nerve at the right elbow cubital tunnel. It shows an echopattern of a muscle. This muscle extends from the ulnar olecranon process to the humerus medial epicondyle. Complete flexion of the right elbow results in significant ulnar nerve compression by this accessory muscle. The ulnar nerve shows edema proximal and distal to the compression. There is no ulnar nerve mass lesion.
The contralateral left elbow was examined for comparison. There is no accessory muscle or ulnar nerve compression with elbow flexion.
Case Discussion
The case shows cubital tunnel syndrome due to an accessory muscle which is anconeus epitrochlearis.