Bilateral incomplete superficial palmar arch

Introduction Superficial palmar arch (SPA) is the dominant vascular structure of the hand and is mainly formed by the anastomosis of ulnar artery (UA) with superficial branch of radial artery (RA), or arteria radialis indicis or arteria princeps pollicis from RA. A classical type of SPA is described as direct continuity between UA and superficial branch of RA confirms the presence of collateral supply in hand [1]. An incomplete arch has an absence of communication or anastomosis between the vessels constituting the arch [2]. Knowledge in variation of vascular pattern of hand gained more importance in microsurgical techniques, reconstructive hand surgeries, preoperative screening of RA harvesting for myocardial revascularization and also in arterial interventions that include RA cannulation and RA forearm flap. In an incomplete SPA, UA do not anastomose with the RA or median artery (MA) and fails to reach the thumb and index finger. There were 4 main types of arch according to Coleman. Type A: Both superficial palmar branches of UA and RA take part in supplying the palm and fingers, but in doing so fail to anastomose and seen in 3.6% of cases. Type B: Only the UA forms the SPA, but the arch is incomplete in sense it does not supply thumb & index finger, and seen in 13.4% of cases. Type C: Superficial vessels receive contribution from both UA & MA, but without anastomosis, and seen in 3.8% of cases. Type D: RA, UA & MA all give origin to superficial vessels but do not anastomose and seen in 1.1% of cases. The present study belongs to type A, a rare and complex bilateral type [3]. Type A incomplete SPA leads to an increased vulnerability to digital ischemic changes following trauma or RA harvesting or RA interventions, and hence prior screening of presence of viable collateral circulation in hand is highly recommended [4]. This variation also assumes importance in obstruction of arteries at the level of wrist occurring in hypothenar hammer syndrome and in connective tissue diseases [3].