Three in one - unusual palmaris longus muscle anatomical variation.

Abstract

The palmaris longus muscle (PLM) is one of the most variable muscles in human body, pre-senting a wide range of morphological variants such as reversed course, biventer muscle, bi-furcated tendon or total agenesis. Their clinical impact is particularly important in diagnosis and treatment of carpal tunnel syndrome and reconstructive surgery. We present a case of PLM including a previously undescribed combination of variations. A routine dissection of male cadaver aged approximately 60 demonstrated a biventer muscle, with superior and inferior belly being interrupted by a long tendon. The inferior belly passed deep to the flexor retinaculum and its terminal tendon connected to flexor digitorum superfi-cialis tendon for 5th finger. The clinical importance of variations found have been described separately, including unsuita-bility of biventer muscles for tendon reconstruction and increased risk for developing carpal tunnel syndrome in patients with PLM tendon passing deep to the flexor retinaculum. In conclusion, as another variation of PLM is described, it is crucial to bear in mind the poten-tial morphological types of the muscle in diagnosis and treatment of patients, especially in surgery of the hand and forearm.