During routine dissection, of the right upper limb of a 70 years old donated embalmed male cadaver in the Department of Anatomy, K.J. Somaiya Medical College, Sion, Mumbai, India, we observed an additional muscle slip of flexor carpi ulnaris with incomplete superficial palmar arch. The additional belly originated from the lower part of the flexor carpi ulnaris muscle and crossed ulnar nerve, ulnar vessels and median nerve. The additional belly merged with the flexor retinaculum. The superficial palmar arch was formed alone by the ulnar artery on medial side but there was no contribution from the radial artery on the lateral side. The pattern of nerves and vessels in the forearm was normal. The variation was unilateral and the left upper limb was normal. The photographs of the additional muscle slip of flexor carpi ulnaris with incomplete superficial palmar arch were taken for proper documentation. The awareness of additional muscle slip of flexor carpi ulnaris is clinically important for surgeons dealing with entrapment or compressive neuropathies, orthopaedicians operating on the fractures of radius or ulna or both and plastic surgeons who are using the flexor carpi ulnaris muscle pedicle flap to improve blood supply and soft tissue coverage at the non union site of the proximal ulna for restoration of elbow function. A lack of knowledge of such type of variations might complicate surgical repair. The knowledge of variations of vascular pattern of hand gained more importance in microsurgical techniques, reconstructive hand surgeries, preoperative screening of radial artery harvesting for myocardial revascularization and also in arterial interventions that include radial artery cannulation and radial artery forearm flap.