Answer to 007’s Q
Correct answer is E. The location of the organs of the abdominal cavity, whether they are intraperitoneal or retroperitoneal, is a function of development. The gastrointestinal system, initially a tube, develops within the mesentery, and all possess a dorsal and ventral mesentery. In time, the tube rotates and some parts lose their dorsal mesentery. It is these organs that will ultimately be found in the retroperitoneal space, i.e., they lack a dorsal mesentery. In a cadaveric dissection, the retroperitoneal organs are not mobile, whereas the intraperitoneal organs are mobile and can be easily moved within a particular dissection field. Of the indicated structures, the caecum is often mistaken as being retroperitoneal. The ascending colon, descending colon, rectum and anal canal are retroperitoneal structures. The descending colon is often clearly visible in a dissection, but understand it is behind the retroperitoneum that may be quite transparent. Nevertheless, when trying to move the descending colon, it cannot be elevated unless the peritoneum is destroyed.
Answer to this question is based on material presented in lectures 7 of the Abdomen Lecture Series.
= Gall bladder
= Transverse colon
= Caecum
= Transverse colon
= Descending colon