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Emergency Surgery
Published in Tjun Tang, Elizabeth O'Riordan, Stewart Walsh, Cracking the Intercollegiate General Surgery FRCS Viva, 2020
Alastair Brookes, Yiu-Che Chan, Rebecca Fish, Fung Joon Foo, Aisling Hogan, Thomas Konig, Aoife Lowery, Chelliah R Selvasekar, Choon Sheong Seow, Vishal G Shelat, Paul Sutton, Colin Walsh, John Wang, Ting Hway Wong
A Meckel's diverticulum is a congenital abnormality of unknown cause. It is a true diverticulum and contains all layers of the intestinal wall. It results from incomplete obliteration of the vitelline duct in the embryo (the vitelline duct connects the GI tract of the embryo to the yolk sac before the placenta is functional). Due to its origin, a Meckel's diverticulum may contain gastric or pancreatic mucosa.
Kinetics and Metabolism
Published in Lars Friberg, Tord Kjellström, Carl-Gustaf Elinder, Gunnar F. Nordberg, Cadmium and Health: A Toxicological and Epidemiological Appraisal, 2019
Gunnar F. Nordberg, Tord Kjellström, Monica Nordberg
A more detailed localization of cadmium in the embryo was reported by Dencker56 using autoradiographic techniques. Cadmium was localized in the primitive gut wall and vitelline duct. The pattern of embryonic uptake was followed up over time. Uptake was found to stop abruptly at day 9 of gestation in the hamster (day 9.5 in the mouse). This is the time when the vitelline duct closes. Injections of relatively high doses of cadmium to hamsters have been reported to give rise to teratogenicity when they are given during the early period of gestation (Volume II, Chapter 11, Section VI.).
Ultrasound in the First Trimester
Published in Asim Kurjak, CRC Handbook of Ultrasound in Obstetrics and Gynecology, 2019
Asim Kurjak, Vincenzo D’Addario
From 7 weeks of menstrual age onward, it is possible to visualize, almost constantly, a 4-to 6-mm, round cystic structure lying adjacent to the fetus, corresponding to the secondary yolk sac (Figures 22 to 24).13 It derives from the primitive yolk sac which develops from the inner cell mass on the side opposite to the amniotic cavity (Figure 3). As a result of the enlargement of the amniotic cavity, and of the transverse folding of the embryo, part of the yolk sac is incorporated into the embryo at the midgut, and the resulting secondary yolk sac is connected to the embryo by the yolk stalk or vitelline duct (Figure 8). With the continuous expansion of the amnion, the elongated yolk sac is embedded into the mesoderm of the umbilical cord, and the yolk sac is pressed against the chorion by the expanding amniotic cavity (Figure 11). It may be found generally near the point where the umbilical cord is attached to the placenta, and it is sometimes possible to confirm its extraamniotic location by visualizing both the yolk sac and the amniotic membrane on the same scan (Figure 25).
Meckel's diverticulum in the adult: surgical treatment
Published in Acta Chirurgica Belgica, 2019
Ismael Mora-Guzmán, José Luis Muñoz de Nova, Elena Martín-Pérez
Meckel’s diverticulum (MD) is a true congenital diverticulum occurring in the distal ileum that is a remnant from the incomplete obliteration of the vitelline duct. The first report was in 1598 by Fabricius Hildanus [1], and later it was named by Johan Friederich Meckel who described the diverticulum’s anatomy and embryology in 1809 [2]. MD is the most common congenital anomaly of gastrointestinal tract, with general population prevalence around 2% [1]. MD is commonly asymptomatic, with a rate of complication of 4–6% [3]. Because of the rare incidence of complications from MD, majority of the publications have reported either small series or isolated cases. Surgical treatment is the best option for management of complicated diverticula, but prophylactic resection of asymptomatic MD incidentally discovered in adults remains still unclear [4–7].
Difference between right-sided and left-sided colorectal cancers: from embryology to molecular subtype
Published in Expert Review of Anticancer Therapy, 2018
Seung Yoon Yang, Min Soo Cho, Nam Kyu Kim
The endodermal gut tube created by body folding during the fourth week of gestation consists of a blind-ended cranial foregut, a blind-ended caudal hindgut, and a midgut open to the yolk sac through the vitelline duct [11]. The midgut forms the distal duodenum, jejunum, ileum, cecum, ascending colon, and proximal two-thirds of the transverse colon. The hindgut forms the distal third of the transverse colon, the descending and sigmoid colon, and the upper two-thirds of the anorectal canal. Just superior to the cloacal membrane, the primitive gut tube forms an expansion called the cloaca. During the fourth to sixth weeks, a coronal urorectal septum partitions the cloaca into the urogenital sinus, which will give rise to urogenital structures, and a dorsal anorectal canal [12]. As the right and left sides of the colon derive from different embryologic origins, anatomically, the proximal colon receives its main blood supply from the superior mesenteric artery with its capillary network being multilayered. The distal colon is perfused by the inferior mesentery artery. Between these two main sources, there is a watershed area located just proximal to the splenic flexure where branches of the left branch of the middle colic artery anastomose with those of the left colic artery. This area represents the border of the embryologic midgut and hindgut. Venous drainage of the colon largely follows the arterial supply with superior and inferior mesenteric veins draining both the right and left halves of the colon.
Meckel’s diverticulum in an adult with iron deficiency
Published in Baylor University Medical Center Proceedings, 2021
Gowthami Kanagalingam, Vrinda Vyas, Anuj Sharma, Divey Manocha
Meckel’s diverticulum is the result of an incomplete obliteration of the vitelline duct, which usually obliterates during the 6th to 10th week of gestation.1 The blood supply is derived by the right vitelline artery, which arises from the superior mesenteric artery.3 The rule of two is often applied for Meckel’s diverticulum, including prevalence of 2% in the general population, length of 2 inches, and 2 feet from the ileocecal junction.4 Two-thirds of patients have ectopic mucosa in the Meckel’s diverticulum, which is usually gastric mucosa, but pancreatic or colonic tissue can also be found.5