Bilateral anatomical variations of the hand. A case report

The anatomical complexity of the upper extremity is reflected in the vast array of structural variation and anomalies that can be observed. Variations and developmental anomalies have been reported in the vasculature, innervation, or musculoskeletal structures of the limb. While anomalies tend to involve multiple structures, variations tend to be more subtle and restricted to individual structures with limited physiological impact. Routine dissection of the hands of a female cadaver revealed bilateral anatomical variations. Firstly, the palmaris longus had multiple distal tendinous insertions bilaterally. Secondly, Berrettini type nervous communications were observed bilaterally between the common digital branches of the ulnar nerves and medial common digital branches of the median nerves. Finally, vascular supply for both hands displayed a number of anomalies of the radial and ulnar arteries. In the right hand, there was a small midline anastomosis between the radial and ulnar arteries while it was absent in the left hand, leading to an incomplete superficial palmar arch. In both hands, the location and pattern of arterial supply rendered the vessels vulnerable to injury and occlusion. Absence of collateral blood supply between the ulnar and radial arteries in the left hand, as well as the superficial location of the superficial palmar radial arteries made the hands of this individual particularly susceptible to ischemic injury. Vascular abnormalities of this nature are routinely screened for prior to procedures of the hand. Anatomical variations of the vasculature, innervation and musculature of the hand and wrist are common. This case displays a unique accumulation of such variations in both hands of a cadaveric specimen. • A cadaveric dissection revealed that thetendon of the palmaris longus muscles present multiple and variable insertions bilaterally. • The radial arteries followed an unusually superficial pathway over the thenar eminences. • The arterial pattern of the left hand was supplied by an incomplete superficial palmar arch.