Background. Branching pattern of inferior mesenteric artery (IMA) and pattern of vascular supply to the left colon and rectosigmoid areas, though important during colorectal surgery, display ...interethnic variations. Further, these regions have notable vascular “weak points” reported to be highly susceptible to ischemic colitis. This study aimed at evaluating the branching pattern of IMA in a black African population. Materials and Methods. Fifty-seven formalin-embalmed cadavers (28 Male, 27 Female) were studied. The length, branching pattern, and diameter of IMA at its origin were recorded. Results. IMA mean length and diameter at origin were 30.57±10.0 mm and 4.10 ± 0.9 mm, respectively. IMA most frequently branched into left colic artery and a common sigmoid trunk in 23 cases while the classical branching pattern was observed in only 7 cases. Colic marginal artery was absent at the splenic flexure and sigmoid colon in 7 and 5 cases, respectively. Arc of Riolan was observed in 9 cases. Conclusion. Branching pattern of IMA shows variations from the previously reported cases which might help account for some of the untoward outcomes observed following colon surgery. An angiographic study to further delineate functionality of the arterial anastomoses in this region is recommended.
Background. Topography of the appendix influences its mobility, degree of mobilization of the cecum, and need for additional muscle splitting during appendectomy. Although appendectomy is a common ...surgical procedure, there is a paucity of data on its topography in black Africans. Methods. The position and length of the appendix and relation of the appendicular base with spinoumbilical line were determined in 48 cadavers obtained from the Department of Human Anatomy, University of Nairobi, Kenya. Results. The commonest appendicular types in males were retrocecal 10 (27%) while in females was subileal 4 (36.4%). The average length of the appendix was 76.5 ± 23.6 mm. The base of the appendix was located along, below, and above the spinoumbilical line in 25 (52.1%), 9 (18.8%), and 14 (29.2%) cases, respectively. Conclusion. The topography of appendix in Kenyans shows variations from other populations. Knowledge of these variations is important during appendicectomy.
Introduction. Histologic changes which occur in the tunica adventitia during initiation, progression, and complications of atherosclerosis are seldom reported. This study aimed at describing the ...features of atherosclerosis in the tunica adventitia of two of the commonly afflicted arteries, namely, left anterior descending coronary and common carotid in black Kenyans. Materials and Methods. Specimens from 108 individuals 76 males and 32 females, mean age 34.6 were processed for paraffin embedding. Seven micron thick sections were stained with Mason’s trichrome and Haematoxylin/Eosin and examined with a light microscope. Results. Features of atherosclerosis were present in the tunica adventitia of 14.8% of left anterior descending arteries and 11.1% of common carotid arteries. Increase in adventitial thickness was associated with increased density of vasa vasora in 8.3% of both arteries. In the left anterior descending and common carotid arteries, 6.5% and 3.7% of cases, respectively, the tunica adventitia thickened without intimal hyperplasia. Conclusion. Features of atherosclerosis occur in the tunica adventitia of coronary and carotid arteries in over 10% of the black Kenyans studied. These features often precede the intimo medial changes. Tunica adventitia should therefore be prioritized in evaluation for atherosclerosis, in individuals at risk. This may enhance early detection and intervention.
Tunica adventitia was previously considered an inert fibrous layer only involved in nutritional and physical support of the arterial wall. Recent studies reveal that it is an important dynamic layer ...actively involved in the regulation of vascular structure, function, response to injury and disease processes especially atherosclerosis. Many anatomical studies on arteries, however, still make only peripheral reference to it, without elucidating its detailed structure. Knowledge of the latter is important in understanding pathobiology and interventional approaches to atherosclerosis. This review, therefore, aims at consolidating contemporary literature on the structure and clinical significance of the arterial tunica adventitia. Google literature search was done using the key words tunica adventitia combined with: artery, aorta, cells, cell types, collagen, elastic fibres, vasa vasora, lymphatics, nerves, atherosclerosis. There is overwhelming evidence that the tunica adventitia comprises multiple types of collagen and elastic fibres arranged in various directions, a wide variety of cells including fibroblasts, smooth muscle, pericytes, myofibroblasts, leukocytes, mononuclear phagocytic, defence, mesenchymal stem and mast cells; vasa vasora including microvasculature, lymphatics and neural elements. The exact cellular, fibre composition and orientation vary between various arteries and regions of the same vessel. Its components are involved in the initiation, progression and complications of atherosclerosis. In conclusion, the tunica adventitia is an active dynamic layer which, besides mechanical and nutritive functions; has metabolic, regulatory and defence roles that are critical in arterial homeostasis and atherosclerosis. Vascular studies should always include detailed analysis of the biology of the tunica adventitia.Key words: Tunica adventitia, cells, fibres, vessels, nerves, atherosclerosis
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