Sigmoid volvulus demonstrates geographical, racial, and gender variation. This autopsy study was undertaken to establish morphological differences of the sigmoid colon and its mesocolon in which the length and other characteristics were assessed. A total of 590 cadavers were examined (403 African, 91 Indian, and 96 White). Length and height of the sigmoid colon and mesocolon were significantly longer in Africans, and mesocolon root was significantly narrower in Africans. Mesocolic ratio for Africans, Indians, and Whites was 1.1 ± 0.8, 1.8 ± 0.7, and 1.9 ± 1.0, respectively. Africans had a significantly high incidence of redundant sigmoid colon with the long-narrow type and suprapelvic position predominating (P = 0.003); the opposite applied to the classic type. There was no difference in sigmoid colon length, mesocolon height, and width between males and females in all population groups. Among Africans, the long-narrow type was more common in males, and the classic and long-broad types were more common in females. Splaying of teniae coli and thickening of the mesentery were more common in Africans. Tethering of the sigmoid colon to the posterior abdominal wall was less common in Africans compared with other population groups. In conclusion, the sigmoid colon was longer, and the sigmoid mesocolon root was narrower in Africans compared with the other population groups, and the sigmoid colon had a suprapelvic disposition among Africans. In Africans, the sigmoid colon was longer in males with a long-narrow shape. These differences may explain geographical and racial differences in sigmoid volvulus.
African patients had the longest combined length of the rectum and sigmoid colon translating into a long sigmoid colon. They also had the highest number of redundant sigmoid colon. This may explain the high incidence of sigmoid volvulus in African patients.
SUMMARY:The morphology of the sphenoid air sinuses is variable amongst populations. The variation in terms of the morphology of this air sinus is particularly important in cranial base surgery. This study aimed to illustrate the three dimensional (3D) morphology of the sphenoid air sinus across ages 1 to 25 years in a South African population. The frequency of the sphenoid sinus characteristics viz. its presence, shape and septa was observed in 3D reconstructed sphenoid sinus models. The sample (n=480 patients) consisted of 276 males and 204 females, 1-25 years and of two population groups viz. black African and white. The sphenoid air sinus was present in (442/480) 92.1 % on the right and in (441/480) 91.9 % on the left. The sphenoid air sinus was absent in 7.9 % and 8.1 % on the right and left sides respectively. Of those present, six different shapes were identified in the anterior/coronal view. Overall, the main shape identified in the anterior view, was quadrilateral on the right (n=243; 50.6 %) and left (n=238; 49.6 %). There was no association between the shape anteriorly and sex or population groups. However, three forms in the lateral view viz. sellar, presellar and conchal types were documented. The main shape identified was the sellar type on both sides (45.2 % R; 49 % L). Laterally, there was an association between shape and sex, on the left side only, and, between the population groups (p<0.05). Intersinus septa were observed in 90.2 % and located predominantly central in 55.4 %. The maximum amount of partial intrasinus septa observed was up to 7 septa. An in depth analysis and classification of the three dimensional form of the sphenoid air sinus according to age 1-25 years was documented in this study. This study proposed a classification of the air sinus utilizing its three dimensional form. The classification illustrated how the air sinus developed within the sphenoid bone and grows into its surrounding parts in both a lateral and posterior direction.
The origin of the sigmoid colon is considered constant as is the V-shaped attachment of the sigmoid mesocolon attachment. This study was undertaken to establish anatomical variations in the level of origin of the sigmoid colon (590 autopsies; 403 Africans, 91 Indians, and 96 Whites), and the shape of the attachment of the sigmoid mesocolon (211 autopsies, 127 Africans, 47 Indians, and 37 Whites) in different population groups. The low-level origin was significantly less common among Africans compared with the other population groups (P = 0.003) and the high-level origin was significantly more common in Africans (P = 0.003). A midlevel origin was similar in all three groups. The shape of the mesocolon attachment was either straight (94), inverted U-shaped (79), or inverted V-shaped (38). The straight shape was more common in Whites (Whites vs. African and Indian P = 0.003), and the U-shape more common in Africans (African vs. Whites P = 0.042). The distribution of the V-shape was similar. There are anatomical variations in the level of origin of the sigmoid colon from the descending colon as well as in the shape of the attachment of its mesocolon. These variations are population based.
The extradural supraodontoid space lies anteriorly at the craniocervical junction (CCJ) between the alar ligaments and foramen magnum. It occupies the space between the tectorial and atlanto-occipital membranes. A variety of benign and traumatic lesions may result in neurological compression here with harmful effects. Decompression by the transoral surgical approach often provides relief from these effects. Knowledge of the detailed microanatomy of this space is fragmentary. The purpose of this study was to identify the boundaries and contents of this space by microdissection. Twenty-three en bloc preserved adult cadaveric specimens of the CCJ were dissected to identify the boundaries and contents of the supraodontoid space. The posterior bony elements of the CCJ were removed to enable microdissection (Zeiss DXE Microscope 4-40x) from the tectorial membrane (TM) forwards. The cave-like space faced posteriorly. It had a roof which extended into a wall (anterior atlanto-occipital membrane), a floor (superior surface of the alar ligament), and a mouth covered by the TM. The apical ligament and a thin lining membranous fatty layer divided the cave into a pair of symmetrical halves. The contents, from dorsal to ventral, lay deep to a thin subtectorial membrane. These were the superior fasciculus of the cruciate ligament, a fat-ensheathed knot of plexiform veins (which communicated with the surrounding CCJ vertebral venous plexuses), an arterial arcade between the veins, a pair of fat pads, and branches of the sinuvertebral nerves of the CCJ (lying on the floor). No synovial membrane was found. Knowledge of the anatomy of the apical cave may be of some assistance in transoral (extra- and transdural) surgical approaches to the anterior CCJ region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.