Two muscular variations in the elbow associated with the anterior interosseous nerve

Abstract

The coexistence of different muscular-neurovascular variations is of significant clinical importance. A male cadaver, 76 years old at death, was subjected to routine anatomical dissection; the procedure was performed for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz. The right forearm and hand were dissected using standard techniques according to a strictly specified protocol. The presence accessory head of the flexor pollicis longus may potentially compress the anterior interosseous nerve. The present case report describes a rare variant of the ulnar head of the pronator teres, characterized by two independent bands (i.e., two proximal attachments). The main band originates from the coronoid process and the second originates from the tendon of the biceps brachii. This type of attachment could potentially affect the compression of the ulnar artery running between the two bands. Additionally, the accessory head of the flexor pollicis longus was observed, which started on the medial epicondyle; its coexistence with a high division median nerve creates a potential pressure site on the anterior interesosseous nerve.

Keywords: Anterior interosseous nerve; Case report; Flexor pollicis longius; Median nerve; Pronator teres.

Fig. 1.

1 Complete view of the forearm. Right forearm. Anterior view. Visible accessory head of the flexor pollicis longus. AHFPL accessory head of the flexor pollicis longus. PT pronator teres muscle AIN anterior interosseous nerve. 2 Proximal part of the forearm. Anterior view of the right forearm. BM brachialis muscle BB biceps brachii AHFPL accessory head of the flexor pollicis longus PT pronator teres muscle