A Gantzer muscle may be associated with weakness of which nerve?

The Gantzer muscle, which is an anatomical variant commonly found as a belly of the flexor pollicis longus muscle, is believed to be innervated by the anterior interosseous nerve. This nerve is a branch of the median nerve and primarily supplies the deep muscles of the forearm, including the flexor pollicis longus, flexor digitorum profundus, and pronator quadratus.

When there is an anatomical variation like the Gantzer muscle, it may exert unusual mechanical pressure or anatomical changes that can impact the function of the anterior interosseous nerve. Therefore, individuals with a Gantzer muscle may subsequently experience weakness in the muscles innervated by this nerve, particularly affecting activities that require flexion of the thumb and the index finger.

Understanding this relationship is crucial for recognizing why the anterior interosseous nerve is linked to the Gantzer muscle. In clinical practice, this knowledge can guide diagnostic approaches to nerve weaknesses, especially in cases where atypical muscle anatomy is detected.