The hand is the most complex part of the human body, involved in skilled movements and fine handling of objects. The human hand can be easily modulated to carry out certain compound movements with great precision, as per our need. Complex skilled movements require the hand to be placed and held in various anatomical positions. As a result, the entire framework of the human hand is supplied with an abundance of highly branched and anastomosing arteries which provides adequate blood supply [1,2].

The earliest evidence of anatomical study on the vascular system of the hand dates back to the 16th century. Andreas Vesalius, in his publication, 'De Humani Corporis Fabrica' described the arterial supply of the hand. However, in his study, he did not specifically mention the presence of superficial and deep palmar arches. In 1961, Coleman and Anson [1] reported the presence of superficial and deep palmar arches in a study carried out on 650 cadavers. Furthermore, this was also later confirmed by Gellman et al., wherein they stated that both arterial arches were present in all their cases [2].

The arterial supply of the hand is by both, ulnar and radial arteries. The terminal parts of the ulnar and radial arteries on reaching the palmar aspect of the hand anastomose with each other to form superficial and deep palmar arches. The superficial branch remains to be a direct continuation of ulnar artery and forms the main contribution of the superficial palmar arch (SPA). The arch is eventually completed by one of the branches of the radial artery. The superficial palmar arch then gives four branches. One of which happens to be a proper branch to the little finger medially, and the other three are common digital arteries. These common digital arteries then further subdivide in pairs along the web spaces to form the proper palmar digital arteries. These all put together supply the medial three and a half fingers of the hand [3].

The human hand is supplied mainly by the superficial palmar arch (SPA) and deep palmar arch (DPA). The SPA forms a vascular arcade across the palm. The SPA can be classified into 'complete' and 'incomplete' SPA, depending on the presence or absence of anastomosis between the vessels forming the SPA [2]. The most classical form of SPA is the 'complete radio-ulnar' type, which is usually formed between the superficial branch of ulnar artery and is completed by a branch of the radial artery [1].

Anatomical variations have been observed with SPA and its contributing arteries which have been reported in literature [4,5]. It has been suggested that certain regulatory factors like hemodynamic forces, availability of oxygen and nutrient requirements during angiogenesis play a role in determining the arterial pattern at the time of foetal development. It should be also noted that the arterial patterns are highly reproducible and therefore genetic basis for the occurrence of such variations should not be undermined [6].

With the advent of microvascular surgeries for revascularization of the hand, replantations, grafting of various parts of the limbs and correcting deformities, knowledge of the arterial variations of the hand is essential for carrying out successful hand surgeries. More recently, radial arterial grafts are being used in bypass surgeries. The presence of a complete palmar arch and its proper identification are necessary in order to extract the radial artery [7]. Although there are many previous studies on SPA, they are most often done on dissected embalmed cadavers which make it hard to distinguish the minute branches of SPA. To bridge the gap, the present study aims in executing a meticulous dissection to find out the frequency of variations in SPA patterns using coloured silicone gel injection technique.

The patterns of the superficial palmar arch were categorized based on the classification established by Coleman and Anson [1] (Table 1).

Out of the 20 dissected hands, 19 hands (95%) exhibited a complete superficial palmar arch (Group I), while 1 hand (5%) presented an incomplete arch (Group II). Among the 19 complete arches, 18 hands (94.7%) were Type A (classical radio-ulnar arch, Figure 3), and 1 hand (5.3%) was Type B (ulnar-derived arch, Figure 4). The single incomplete arch was Type F (non-anastomosing radio-ulnar type, Figure 5) (Table 2).

Bilateral asymmetry was noted in two cadavers: in one cadaver, the right hand had a complete SPA of Type B and the left hand had Type A; in another cadaver, the right hand had an incomplete SPA of Type F and the left hand had a complete SPA of Type A.

The human hand is endowed with a rich anastomotic network mainly contributed by the superficial palmar arch and deep palmar arch [1,2]. The 95% prevalence of complete arches observed in the present study closely matches previous reports by Jose et al. (96%) [9], Suma et al. (95%) [10], Ramakrishnan et al. (92%) [8], Bilge et al. (86%) [12], and Joshi et al. (82%) [11] (Table 3), while contrasting with series reporting higher incomplete arch frequencies (e.g., Sarkar et al. 55% [13], Fazan et al. 52% [14], Valeria et al. 47.5% [15], and Sullivan & Mitchell 46.8% [16]).

In terms of subtypes, the classical radio-ulnar Type A predominated (90.0% overall, 94.7% of complete arches), corroborating Madhyastha et al. (93.75%) [17] and Suma et al. (95%) [10]. The non-anastomosing radio-ulnar Type F was the most frequent incomplete variant. Bilateral asymmetry in two cadavers confirms observations by Bilge et al. [12].

Clinical implications of these vascular variants are substantial. Free arterial anastomosis ensures rapid collateral healing but creates severe hemorrhagic risk during palmar incisions or drainage of localized pus [18]. Knowledge of arch completeness is imperative prior to radial artery harvesting in coronary artery bypass grafting (CABG) or during reconstructive microvascular limb and hand surgery [7].

The use of RTV 116 silicone compound via vascular injection technique facilitated clear visualization of the superficial palmar arch and its fine digital ramifications. A high prevalence of complete arches (95%), predominantly of classical radio-ulnar Type A (90%), was identified alongside instances of bilateral anatomical asymmetry. Detailed appreciation of palmar arterial variations is essential for safe hand surgery, pus drainage, and radial artery graft harvesting.