Surgical Resection of a Reversed Palmaris Longus Muscle Causing Chronic Exertional Compartment Syndrome in a Competitive Swimmer: A Case Report

The palmaris longus is a superficial muscle located on the volar side of the forearm. It usually arises from the medial epicondyle of the humerus and inserts into the palmar aponeurosis of the wrist. However, the palmaris longus is one of the most variable muscles in the human body. The most frequent anatomic variation is complete agenesis, which is found in up to 25% of the population.9,12 Other variations include reversed, duplicated, bifid, or hypertrophied palmaris longus muscles, which can be of clinical significance by causing effort-related pain with or without median or ulnar nerve paresthesia.1,3,4,11 According to the literature, treatment of these conditions consists of excision of the anomalous muscle, decompressive fasciotomy, median or ulnar nerve release, or a combination of the aforementioned.3 We report a case in which a reversed palmaris longus muscle caused exertional forearm pain without median or ulnar nerve paresthesia in an adolescent competitive swimmer. Treatment consisted of surgical excision of the anomalous muscle, which led to full relief of pain.