Question 1#

A 74-year-old man with biopsy-proven rectal adenocarcinoma is undergoing a low anterior resection. Which layers must be stapled through when resecting the distal portion of resection specimen?

A. Mucosa, submucosa, circular muscle layer, longitudinal muscle layer, and serosa

The wall of the colon and rectum are made of five separate layers: mucosa, submucosa, circular muscle layer, longitudinal muscle layer, and serosa. The mid and lower rectum lack serosa so this layer would not be stapled through if the surgeon were stapling through the mid or lower rectum.

Question 2#

Which layer of muscle joins together to form the internal anal sphincter?

A. Circumferential muscle layer

The inner circular muscle joins to form the internal anal sphincter. The subcutaneous, superficial, and deep external sphincter surrounds it. The deep external anal sphincter is an extension of the puborectalis muscle.

Question 3#

A 24-year-old woman with medically refractory ulcerative colitis decides to undergo a total colectomy. During this procedure, where would it be most appropriate to look for the inferior mesenteric vein in order to ligate it? 

A. Look for the inferior mesenteric artery; the veins of the colon usually parallel with the corresponding arteries

The inferior mesenteric vein does not run with the inferior mesenteric artery. Instead, it travels cranially in the retroperitoneum over the psoas and then posterior to the pancreas to join the splenic vein. The vein is often ligated at the inferior edge of the pancreas during a colectomy. 

Question 4#

An anatomy class is dissecting out the rectum. What are the correct fascial arrangements that they will encounter during this dissection?

A. The presacral fascia separates the rectum from the presacral venous plexus and the pelvic nerves; Waldeyer fascia extends forward and downward and attaches to the fascia propria at the anorectal junction. Denonvilliers fascia separates the rectum from the prostate and seminal vesicles in men and from the vagina in women

The presacral fascia separates the rectum from the presacral venous plexus and the pelvic nerves. The rectosacral fascia ( Waldeyer fascia) extends forward and downward and attaches to the fascia propria at the anorectal junction. Anteriorly, Denonvilliers fascia separates the rectum from the prostate and seminal vesicles in men and from the vagina in women.

Question 5#

Choose the correct definition of intestinal malrotation:

A. At the 4th week of gestation the midgut herniates through the abdominal cavity, rotates 270° clockwise around the superior mesenteric artery and then travels to its resting place in the abdomen during the 10th week

During the 6th week of gestation, the midgut herniates out of the abdominal cavity and rotates 270° counterclockwise around the superior mesenteric artery and travels to its resting position in the 10th week of gestation. Failure of the midgut to rotate and return to the abdominal cavity during the 10th week of gestation results in intestinal malrotation.