The thoracic surface anatomy of adult black South Africans: A reappraisal from CT scans.

Surface landmarks or planes taught in anatomy curricula derive from standard anatomical textbooks. Although many surface landmarks are valid, clear age, sex, and population differences exist. We reappraise the thoracic surface anatomy of black South Africans. We analyzed 76 (female = 42; male = 34) thoracoabdominal CT-scans. Patients were placed in a supine position with arms abducted. We analyzed the surface anatomy of the sternal angle, tracheal, and pulmonary trunk bifurcation, azygos vein termination, central veins, heart apex, diaphragm, xiphisternal joint, and subcostal plane using standardized definitions. Surface anatomy landmarks were mostly within the normal variation limits described in previous studies. Variation was observed where the esophagus (T9) and inferior vena cava (IVC) (T8/T9/T10) passed through the diaphragm. The bifurcations of the trachea and pulmonary trunk were inferior to the sternal angle. The subcostal plane level was positioned at L1/L2. The origin of inferior mesenteric artery was mostly inferior to the subcostal plane. Sex differences were noted for the plane of the xiphisternal joint (P = 0.0082), with males (36%) intersecting at T10 and females (36%) intersecting at T9. We provide further evidence for population variations in surface anatomy. The clinical relevance of surface anatomical landmarks depends on descriptions of normal variation. Accurate descriptions of population, sex, age, and body type differences are essential. Clin. Anat. 29:1018-1024, 2016. © 2016 Wiley Periodicals, Inc.

The horseshoe kidney: Surgical anatomy and embryology.

Horseshoe kidneys are a common, yet enigmatic, renal malformation. This review critically appraised the literature surrounding the embryology, etiology and clinical anatomy of horseshoe kidneys. The systematic literature search produced 104 articles, and 56 primary and further secondary references. There were several etiological theories regarding horseshoe kidneys. The established view was that during ascent, the kidneys come into close apposition as they pass through an arterial fork. Another possible mechanism related to lateral flexion of the trunk or rotation of the caudal embryo; the association of asymmetrical horseshoe kidneys with a number of vertebral conditions supported this hypothesis. More recent animal models implicated the notochord and sonic hedgehog signaling. Furthermore, it has been suggested that the isthmus may be the result of ectopic mesenchymal tissue. Surgical anatomy of the horseshoe kidney is complex, due to variability in location, orientation and blood supply. Both arterial and venous anatomy is highly variable. This raised the question of whether anomalous blood supply is the cause or result of abnormal renal position. In the majority of cases, the isthmus contained functional renal parenchyma. In over 90% of cases, fusion between the kidneys occurred at the lower pole. Despite commonly being quoted as 'held back by the inferior mesenteric artery' at L3, in reality the isthmus was only found immediately inferior to this in 40% of cases.

Surface anatomy and anatomical planes in the adult turkish population.

Surface anatomy and anatomical planes are widely used in education and clinical practice. The planes are largely derived from cadaveric studies and their projections on the skin show discrepancies between and within anatomical reference textbooks. In this study, we reassessed the accuracy of common thoracic and abdominopelvic anatomical planes using computed tomography (CT) imaging in the live adult Turkish population. After patients with distorting pathologies had been excluded, CT images of 150 supine patients at the end tidal inspiration were analyzed. Sternal angle, transpyloric, subcostal, supracristal and pubic crest planes and their relationships to anatomical structures were established by dual consensus. The tracheal bifurcation, azygos vein/superior vena cava (SVC) junction and pulmonary bifurcation were usually below the sternal angle while the concavity of the aortic arch was generally within the plane. The tip of the tenth rib, the superior mesenteric artery and the portal vein were usually within the transpyloric plane while the renal hila and the fundus of the gallbladder were below it. The inferior mesenteric artery was below the subcostal plane and the aortic bifurcation was below the supracristal plane in most adults. Projectional surface anatomy is fundamental to medical education and clinical practice. Modern cross-sectional imaging techniques allow large groups of live patients to be examined. Classic textbook information regarding anatomy needs to be reviewed and updated using the data gathered from these recent studies, taking ethnic differences into consideration.

The mucosal folds at the pancreaticobiliary junction.

PURPOSE: The structure and function of the mucosal folds in the terminal bile and pancreatic ducts and hepatopancreatic ampulla are poorly characterised. The distribution, muscularity, and innervation of these folds were investigated. METHODS: The pancreaticobiliary junction was excised from ten cadavers (five male, 66-90 years) and examined histologically by serially sectioning (4-µm thickness) along the length of the terminal bile and pancreatic ducts from the tip of the major duodenal papilla. Three surgical specimens (two male, 63-72 years) were also evaluated. Sections were stained with haematoxylin and eosin, anti-actin (smooth muscle), anti-S100 (innervation), and anti-cholecystokinin (CCK)-A receptor antibodies. ImageJ software was used to compare relative radial fold projection and semi-quantitatively assess the smooth muscle and nerve content. In one additional cadaver specimen, folds were examined by scanning electron microscopy. RESULTS: Mucosal folds in the terminal bile duct were arranged circumferentially in a lattice-like arrangement and were distributed over an average distance of 7.3 mm along the terminal bile duct compared to 4.2 mm along the pancreatic duct (P = 0.001), projected further into the lumen, and were more densely innervated than those in the terminal pancreatic duct. Folds in both ducts contained smooth muscle which was more prominent in folds nearest to the major duodenal papilla. Mucosal folds in cadaver and surgical specimens showed no evidence of CCK-A receptor immunoreactivity. CONCLUSIONS: This study demonstrates that the mucosal folds of the terminal bile and pancreatic ducts contain muscle and nerve fibres, suggesting an active rather than purely passive function.

The arterial supply of the major duodenal papilla and its relevance to endoscopic sphincterotomy.

BACKGROUND AND STUDY AIMS: Arterial bleeding from the major duodenal papilla is an uncommon but potentially life-threatening complication of endoscopic sphincterotomy. We investigated the arterial blood supply of the papilla to determine whether there might be a safer region for sphincterotomy. METHODS: Arteries supplying the major duodenal papilla were studied in 19 cadaver pancreaticoduodenal specimens (nine male, mean age 81 years, range 64 - 97 years) using a combination of microdissection and histology. The number, origin, caliber, and distribution of arteries within 5 mm of the major duodenal papilla were recorded. RESULTS: A total of 98 papillary arteries were identified by microdissection giving a mean of 5.2 arteries (range 3 - 9) per specimen. Papillary arteries originated from three sources: communicating arteries and the posterior and anterior pancreaticoduodenal arcade arteries. The majority of arteries were related to the antero-superior and postero-inferior quadrants of the major duodenal papilla, both at their point of entry into the duodenal wall or bile/pancreatic ducts (microdissection) and in their distribution 5 mm from the tip of the papilla (histology). The combined 10 and 11 o'clock segments of the papilla (as viewed endoscopically) contained only 10 % and 11 % of all papillary arteries on microdissection and histology, respectively, with seven of 19 specimens having no arteries in this region. CONCLUSIONS: This study documents for the first time the distribution of papillary arteries around the circumference of the major duodenal papilla. Arterial bleeding complicating endoscopic sphincterotomy might be reduced by incising the papilla in the 10 - 11 o'clock region rather than the currently recommended 11 - 1 o'clock position.