Anatomy GIT overview-Witwer (Exam 2) Flashcards
Foregut= (contains)
Esophagus; Fundus,
Body, and Antrum of Stomach, Pylorus,
Duodenal bulb and Proximal Descending
Duodenum.
Midgut=
Distal Descending Duodenum,
Transverse Duodenum, and Ascending
Duodenum, Jejunum, Ileum, Cecum,
Ascending and Proximal Transverse Colon
Hindgut=
Distal Transverse Colon,
Descending Colon, Sigmoid Colon,
And Rectum
Embryological Rotation and Fixation of the Foregut, Midgut, and Hindgut
- the foregut rotates _____
- the midgut rotates _______
- clockwise (stomach)
- midgut–> counterclockwise
Embryological Rotation and Fixation of the Foregut, Midgut, and Hindgut:
-Then the bowel is fixed into position, either ____ or _______
intra or retroperitoneal.
Normally, the Stomach and Duodenal bulb are ________, the Descending and Transverse Duodenum are _______
intraperitoneal
retroperitoneal.
The Jejunum and Ileum are _________
Intraperitoneal.
the cecum is intra or retroperitoneal?
The Cecum can be either intra or retroperitoneal
Ascending and descending colon are ______
retroperitoneal
transverse colon and sigmoid colon are _______
intraperitoneal
Rectum is _______
extraperitoneal
Describe the Normal Rotation of the midgut (slide where Witwer wrote out the steps)
- Midgut loop has a cranial limb and a caudal limb
- Midgut loop rotates around the axis of the **superior mesenteric artery
- Midgut loop rotates first 90 degrees to bring the cranial limb to the right & caudal limb to the left during the physiological hernia
- the cranial limb of the midgut loop elongates to form the intestinal coiled loops (jejunum and ileum).
- This rotation is counterclockwise and it is completed to 270 degrees, so after reduction of physiological hernia it rotates to about 180 degrees
Where is the ligament of treitz located?
**LUQ
-if the ligamentum of treitz IS NOT there, you know you had a malrotation. This causes the small bowel to be on the right (when it should be on the left) and you have a thing called Ladd’s band. It pinches the arteries and veins and you get increased edema and blockage of the vessels. You end up with arterial infarction and DEAD bowel. Tx: they go in and cut the Ladd’s band, and reattach the bowel to where it SHOULD be
Intestinal Malrotation with Midgut Volvulus:
-Clinical Sx?
- **billious vomiting
- Hemodynamic instability
- Abdominal distension
(Pts present with: bilius vomiting!!! because the bile duct from the liver comes in and inserts on the lesser curve side of the duodenum. Bile gets in their (its an emulsifier) and it breaks down the fat cells –any time you see bilius vomiting: you know the obstruction is distal to where the common bile duct enters the duodenum )
Intestinal Malrotation with Midgut Volvulus:
Associated congenital defects?
- congenital diaphragmatic hernia
- Congenital heart disease (heterotaxy syndrome)
- Omphalocele
Intestinal Malrotation with Midgut Volvulus:
-management/tx?
*surgical (Ladd procedure)
2 times when you get a malrotation of the midgut Volvulus:
- when you’re a year old or 2 OR after 50 yo
- *high risk for associated congenital defects
- Tx: management= surgical (Ladd Procedure)
Creation of the Peritoneal Cavities and Mesenteries
The complex folding and changes described above during development create the peritoneal cavity and its subcomponents–> the Lesser Sac (Omental Bursa) and the Greater Sac
The Greater Omentum is created from?
the greater curve of the stomach
The Vitelline duct:
- is a remnant of?
- present in __% of the population
- the yolk stalk that is in the area of the umbilicus and attached to the small bowel
- 2%
The Vitelline duct can persist as a _____
*Meckel’s Diverticulum–> and become inflammed, hemorrhage, intussuscept, obstruct or ulcerate
(Normally the vitelline duct disappears in ppl–> if it remains it persists as meckel’s diverticulum)
*Meckel’s diverticulum: KNOW. These PPl have gastric fluid in there and they can present with GI bleeding.
Normally the mesenteric root goes from the left upper abdomen to the _____
right lower abdomen
Note Gastrosplenic and
Splenorenal ligaments and
the Porta Hepatis
?
Is the entire liver covered by peritoneum?
There is a bare area of the liver= that’s NOT covered with peritoneum
Glisson’s capsule=
has lot’s of pain fibers, so when it’s stretched its painful
–Behind the liver is the lesser omentum and the omental bursa
-bigest no no in surgery– you never transect the ____
common bile duct cuz it DOES not heal
Lesser omentum= attachment b/w the stomach and the ____
liver
pouch of douglas=
retrouterin pouch or vesicoretro pouch (in males)
–pus and cancer ends up in those pouches
Right posterior retroperitoneal space=
Morrison’s pouch!!!! KNOW!
=subhepatic posterior recess- behind liver, most dependent space- where ascites/tumors will go. It’s Intraperitoneal
Groin is a weak area in the anterior abdominal wall secondary to the descent of the ________
gubernaculum
—>inguinal hernias
(Gubernaculum= “governs the descent of the testicle” . Hernias can occur in this area)
Hernias can also occur in which areas?
- umbilical
- femoral
- para-umbilical
- incisional
- spigelian
- internal (obturator, greater sciatic, and piriformis) areas
–MC hernias are inguinal hernias**
Muscles of anterior abdominal wall are innervated generally in patterns reflected by:
the dermatomes
How do inguinal hernias form?
There is a weakness in the anterior abdominal wall secondary to the gubernaculum and descent of the Testes and Round Ligament
notes: (There are direct inguinal hernias and indirect
-guys are more prone to getting hernias
-note the superficial inguinal ring: spermatic cord comes through it
-external oblique muscle orientation= “putting something in your pocket”
-transverse abdominus= deepest muscle
-linea alba= “white line in the middle of the 6 pack”
-we uncover the inguinal canal
-inguinal ligament goes form the in anterior interior iliac crest to the
-internal oblique, there is the inguinal ligament and deep to that is the external canal with the spermatic cord
NEED TO KNOW THIS ANATOMY
Indirect Inguinal Hernia=
indirect hernia: comes from the deep inguinal ring and down the inguinal canal and out the superficial inguinal ring (ductus deferens=
Direct Inguinal Hernia=
goes straight out and there’s weakness In the inguinal triangle (or hasselbach’s triangle!!!
Hasselbach’s triangle=
- hasselbach’s traiangle= lateral border of the rectus abdominus, inferior epigastric vessels and iliopubic tract, located superior to the inguinal ligament.
- where 2 types of hernias MC form (indirect and direct hernias)
Abdominal Innervation:
-Which nerves innervate the abdomen?
Extensive nerve plexes supply abdomen – Solar Plexus