Adductor accessorius - An unusual supernumerary adductor muscle of thigh

The knowledge of variant anatomy of medial compartment of thigh is extremely important in surgical procedures requiring obturator nerve block. The nerve block is also recommended for providing additional analgesia following major knee surgeries and for relieving painful adductor muscle spasm. The interfascial injection technique is commonly followed in ultrasound guided obturator nerve block. For this procedure it is imperative to identify the adductor muscles on sonography to inject the anesthetic solution in the intermuscular fascial planes. The presence of an additional muscle can prove useful in myocutaneous flap surgeries for reconstruction especially of perineum. We hereby report a case of such an anomalous supernumerary adductor muscle present between adductor brevis and proximal part of adductor magnus, in an adult Indian male cadaver, recorded during routine dissection in Department of Anatomy, Vardhman Mahavir Medical College and Safdarjung Hospital. The muscle was innervated by the posterior division of obturator nerve. The morphology, embryological basis and clinical aspects are also discussed.