The kidneys receive a rich segmental arterial supply from the renal arteries, which usually arise from the abdominal aorta. Each renal artery typically divides into anterior and posterior divisions, giving rise to five segmental arteries—apical, upper, middle, lower, and posterior—that supply distinct renal segments (Mchonde, 2025). These arteries are end arteries with minimal collateral circulation, making their preservation essential during surgical and interventional procedures (Rani et al.,2014).

The apical and upper segmental arteries are particularly important as they supply the upper pole of the kidney, a region frequently involved in procedures such as partial nephrectomy and renal transplantation (Munusamy et al.,2026). Variations in their origin and branching pattern—such as common trunks or direct origin from the renal artery or aorta—are common and clinically significant, as they may lead to ischemia or surgical complications if unrecognized (Ueda et al.,2026).

With the increasing use of nephron-sparing and minimally invasive techniques, detailed knowledge of these vascular variations is crucial for effective surgical planning and improved outcomes. However, focused studies specifically addressing apical and upper segmental artery variations remain limited.

Therefore, the present study aims to evaluate the morphological variations of the apical and upper segmental branches of the renal artery using dissection and corrosion cast methods and to assess their surgical significance.

A descriptive cross-sectional anatomical study was conducted on 100 adult human kidneys of both sexes. Of these, 82 kidneys were obtained from embalmed cadavers during routine dissection in the Department of Anatomy, and 18 fresh kidneys were procured from the mortuary for corrosion cast preparation. Prior to removal, renal arteries were carefully examined for the presence of accessory or supernumerary branches arising from the abdominal aorta or adjacent vessels. The kidneys were then dissected along with their renal arteries for detailed study. Inclusion Criteria • Adult human kidneys obtained from cadavers and fresh specimens • Kidneys with intact renal artery and segmental branches • Specimens suitable for dissection or corrosion cast preparation Exclusion Criteria • Kidneys with damaged or disrupted renal vasculature • Specimens showing gross pathological changes (tumors, severe infection, trauma) • Previously dissected or mutilated kidneys • Specimens with inadequate preservation or incomplete casting The apical and upper segmental arteries were studied with respect to their origin, branching pattern, and variations using the following methods: 1. Dissection Method (n = 82) The kidneys were washed to remove preservative fluid, and the renal capsule was carefully removed. The renal parenchyma was dissected in a piecemeal manner under water to expose the segmental branches of the renal artery (Sampaio et al.,1992). The apical and upper segmental arteries were identified and traced to determine their origin and branching pattern. Variations were recorded systematically. Each specimen was labelled, documented, and photographed. The dissected specimens were preserved in 5% formalin for further analysis. 2. Corrosion Cast Method (n = 18) Fresh kidneys were washed thoroughly and flushed with saline to remove blood and debris. The renal artery was cannulated, and silicone-based casting material was injected until complete filling of the arterial tree was achieved. The specimens were left undisturbed for adequate setting of the material and subsequently immersed in diluted hydrochloric acid to corrode the surrounding soft tissue. The resulting arterial casts were retrieved, washed, dried, and examined (Cicekcibasi et al.,2005). The morphology and variations of the apical and upper segmental arteries were recorded and photographed. Statistical Analysis: The observed variations were categorized into different types and expressed as frequency and percentage.

The apical segmental renal artery exhibited considerable variation in its origin among the 100 specimens examined. Nine distinct patterns were identified. The most common origin was from the renal artery along with other segmental branches (Type 2, 25%) and least frequent patterns included origin from the abdominal aorta either independently (Type 8, 2%) or in association with upper and posterior segmental arteries (Type 9, 1%). The detailed distribution of the observed variations is presented in Table 1.

Table 1: Variations in the Origin of the Apical Segmental Renal Artery Observed in Dissection and Corrosion Cast Specimens (n = 100)

The upper segmental renal artery demonstrated six distinct patterns of origin in the 100 specimens studied. The most common pattern was origin from the anterior division of the renal artery (Type 1, 30%) and the least common origin from the abdominal aorta along with apical and posterior segmental arteries (Type 6, 1%). The detailed distribution of these variations is shown in Table 2.

Figure 1: Specimen showing type 2 apical segmental artery by dissection method (12) & luminal cast method (98)

Table 2: Variations in the Origin of the Upper Segmental Renal Artery Observed in Dissection and Corrosion Cast Specimens (n = 100)

Figure 2: Specimen showing type 1 upper segmental renal artery by dissection method (2) & luminal cast method (90)

The present study demonstrated that Type 2 apical segmental renal artery, arising directly from the renal artery along with other segmental branches, was the most common pattern (25%), followed by Type 4, originating from or along the upper segmental artery (20%), and Type 1, arising from the anterior division of the renal artery (19%). These findings indicate considerable variability in the origin of the apical segmental artery and suggest that independent branching from the renal artery or formation of common trunks with adjacent segmental arteries is more frequent than a simple origin from the anterior division.

The findings of the present study differ from those of Graves (1954), who reported Type I as the predominant pattern (43.03%), followed by Types II and III (23.03% each). Similarly, Kher et al. (1960) observed Type II as the most common pattern (51.66%), while Type I accounted for 45.28% of cases and Type III was absent. Chatterjee and Dutta (1963) also found Type I to be the most frequent pattern (42.2%), followed by Type IV (29.7%). In contrast, Raghavendra et al. (2012) reported Type IV as the predominant pattern (29.7%), followed by Type III (25%) and Type II (22%), highlighting substantial inter-study variation. Serov (1959) identified Type I as the most frequent arrangement, whereas Mishra et al. (2015) reported a relatively lower incidence of all major patterns, with Type II (16.3%) being the most common.

A notable observation in the present study was the relatively high frequency of common trunk formations (Types 5 and 7), which together accounted for 19% of specimens. These findings support earlier observations that renal arterial segmentation is highly variable and that fusion or persistence of embryonic vascular channels may result in shared origins of adjacent segmental arteries. Furthermore, direct origin of the apical segmental artery from the abdominal aorta (Types 8 and 9) was observed in only 3% of specimens, indicating that such variants are uncommon.

As far as upper segmental artery was concerned, it exhibited six distinct patterns of origin. The most frequent pattern was Type 1 (origin from the anterior division of the renal artery), observed in 30% of specimens, followed closely by Type 2 (origin from the renal artery with other segmental branches) in 28%. Together, these two patterns accounted for 58% of all specimens, indicating that the anterior division and the main renal artery represent the predominant sources of the upper segmental artery. These findings are broadly comparable with those of Chandragirish et al. (2014), who reported Type I superior segmental arteries in 28% of cases. However, the incidence of Type II in the present study (28%) was substantially higher than the 12% reported by Chandragirish et al. Similarly, Type III (common origin with the apical segmental artery) was observed in 20% of our specimens compared with 14% in their study, whereas Type IV showed a lower incidence (10%) than the 20% reported by them.

A notable difference was observed in the occurrence of Type VI, representing origin from the abdominal aorta along with apical and posterior segmental arteries. Chandragirish et al. reported this pattern in 23% of specimens, whereas it was encountered in only 1% of the present series, indicating marked population-based variation in the prevalence of this rare vascular arrangement. Earlier classical studies by Graves and Chatterjee et al. similarly documented substantial variability in the origin of the superior segmental artery. Graves reported a combined incidence of 43.3% for patterns corresponding to Types I and II, while Chatterjee et al. documented 42.2%. The present study demonstrated a higher combined incidence of 58%, reinforcing the predominance of these two branching patterns.

The present study revealed considerable anatomical variation in the origin of the apical and upper segmental renal arteries. While the majority of arteries originated from the renal artery or its anterior division, several less common patterns, including common trunks and direct aortic origins, were also observed. These findings highlight the complexity of renal vascular anatomy and underscore the importance of preoperative vascular evaluation. Awareness of such variations is essential for renal transplantation, partial nephrectomy, and other nephron-sparing procedures to reduce surgical complications and preserve renal function.

1. Mchonde G. Variant Right Renal and Adrenal Arterial Supply with Associated Clinical and Embryological Perspectives. Cureus. 2025;17(12): e99558. Published 2025 Dec 18. doi:10.7759/cureus.99558
2. Rani N, Singh S, Dhar P, Kumar R. Surgical importance of arterial segments of human kidneys: an angiography and corrosion cast study. J Clin Diagn Res. 2014;8(3):1-3. doi:10.7860/JCDR/2014/7396.4086
3. Munusamy, Kumaresan; Achuthan, Sangeetha1; Saikarthik, Jayakumar2; Saraswathi, Ilango3,4. Computed Tomographic Investigation of the Upper Segmental Renal Artery and its Relation with the Major Calyx among Renal Donors: A Radiological Study and Review. Journal of the Anatomical Society of India 75(1):p 48-53, Jan–Mar 2026. | DOI: 10.4103/jasi.jasi_145_25
4. Ueda Y, Nemoto W, Hosoda R, et al. Common trunk branching from the renal artery to the diaphragm, adrenal gland, and testis: a case report with embryological hypotheses by observation. Anat Sci Int. 2026;101(1):97-101. doi:10.1007/s12565-025-00829-2
5. Sampaio FJB, Passos MA. Renal arteries: anatomic study for surgical and radiological practice. Surg Radiol Anat. 1992;14(2):113–117. doi:10.1007/BF01627604
6. Cicekcibasi AE, Ziylan T, Salbacak A, Seker M, Buyukmumcu M, Uysal II. A detailed study of the renal artery in human cadavers and a review of the literature. Folia Morphol (Warsz). 2005;64(2):111–118.
7. Graves FT. The anatomy of intrarenal arteries and its application to segmental resection of the kidneys. Br J Surg. 1952; 42:132-140.
8. Kher GA, Bhargava I, Makhni FS. Internal branching of the renal artery. Indian J Surg. 1960; 22:563-579.
9. Chatterjee SK, Dutta AK. Anatomy of the intrarenal distribution of renal arteries of the human kidney.
10. Raghavendra V, Manjappa P, Telkar A. Renal apical segmental artery variations and its surgical importance. J Clin and Diag Research 2012;6(4):561-563.
11. Serov VV. Segmental arterial distribution in the human kidney. Urology. 1959; 24:6.
12. Mishra GP, Bhatnagar S, Singh B. Anatomical Variations of Upper Segmental Renal Artery and Clinical Significance. J Clin Diagn Res. 2015;9(8):AC01-AC3. doi:10.7860/JCDR/2015/12326.6280
13. Chandragirish S, Nanjaiah CM, Shirur SY, Saheb SH. Study on variations of posterior division of renal artery. Int J Anat Res. 2014;2(4):709–711. doi:10.16965/ijar.2014.532.
14. Graves F T. The aberrant renal artery [synopsis]. Proc of soc of med 1957: 50: 368-370.
15. Chatterjee S K and Dutta A K. Anatomy of the intrarenal distribution of renal arteries of the human kidneys. J of Ind Med Assoc 1963; 40: 155-162.