Anatomic Variations of the Palmaris Longus Muscle

The palmaris longus muscle exhibits significant anatomical variance compared with other muscles of the upper extremity. The most frequent variation is complete absence of the muscle, but a number of other variations exist. These variations include reversed, duplicated, bifid, or hypertrophied palmaris longus muscles. Many authors have reported the variations in case reports and described them using their own terms. In this case report and review of literature, we aim to consolidate the current knowledge regarding the anatomic variations of the palmaris longus muscle and its clinical relevance.