1-6 Anatomy of the Supracolic Compartment Flashcards
What is the supracolic compartment?
Peritonealized area between the thoracoabdominal diaphragm and the transverse colon and its associated mesocolon
What are the contents of the supracolic compartment?
Contains the distal esophagus stomach, spleen, liver, gall bladder, and part one of the duodenum
What abdominal compartment is the transverse mesocolon in?
Since the transverse mesocolon straddles the pancreas, it is retroperitoneal and not in either the supra or infracolic compartment
What is the origin of the esophagus?
cricoid cartilage opposite CV6
What is the course of the esophagus?
- Neck: slightly to the left of the midline
- Upper thorax (TV4): midline
- Middle thorax (TV8): crosses to the left (anterior to aorta)
- Lower thorax (TV10): left of the midline to penetrate the diaphragm
What are the 4 sites of potential constriction for the esophagus?
- At the junction of the pharynx and esophagus, cricopharyngeus m. (upper esophageal sphincter)
- Aortic arch
- Left primary bronchus
- Esophageal hiatus
At what level does the esophagus pierce the diaphragm?
TV10
What ligament allows for independent movement of the esophagus and diaphragm during breathing?
phrenico-esophageal ligament
Attached to the margins of the esophageal hiatus via the phrenico-esophageal ligament (dorsal mesentery). It attaches to the esophagus both superior and inferior to the hiatus, allowing independent movement of the esophagus and diaphragm during breathing
At what level does the esophagus join the stomach?
TV11
What portion of the esophagus is peritonealized?
Mesoesophagus, in abdomen
Describe the right and left borders of the gastro-esophageal junction.
- Right border - continuous with the lesser curvature of the stomach
- Left border - separated from the fundus of the stomach by the cardiac notch
Describe the āz-lineā of the esophagus.
demonstrates an epithelial transitional zone (stratified squamous to simple columnar, aka, āZā line)
Is there a sphincter at the esophageal cardiac junction? What is this important in? What does it prevent?
Although not anatomic, a functional physiologic sphincter exists at the esophageal cardiac junction (L.E.S. lower esophageal sphincter) which appears to be important in regulating the entrance of food into the stomach and in preventing esophageal reflux
What is the arterial supply for the cervical, thoracic, and abdominal portions of the esophagus?
- Cervical portion: Inferior thyroid a.
- Thoracic portion: Branches from the bronchial aa. & from the aorta directly
- Abdominal portion: Esophageal branch of the left gastric a.
How is venous drainage of the esophagus accomplished? What kind of venous systems do the veins drain to?
- Esophageal submucosal veins are drained by venae comitantes of the arterial supply.
- These veins drain to both systemic (subclavian) and portal (azygos) venous systems
How is the stomach secured to the diaphragm? Posterior body wall? What vertebral level?
Fastened securely to the diaphragm superiorly (TV11) via the gastrophrenic ligament
inferiorly to the posterior body wall via its continuity with the retroperitoneal portion of the duodenum (LV1 - LV2)
Why is the stomach mobile? What structures allow it to be mobile?
the remainder of the stomach is only loosely secured by the omenta (greater and lesser), it is highly mobile, so much so, that when sufficiently filled may extend into the major pelvis
What are the curvatures of the stomach?
1) Greater: convex lateral border
2) Lesser: concave medial border
What are the external regions of the stomach?
1) Cardia: indefinite area around esophageal entrance
2) Fundus: portion more superior than cardia
3) Body: area between fundus and pyloric antrum
4) Pyloric portion
What 3 parts make up the pyloric portion of the stomach?
Pyloric antrum: expanded portion proximal to pyloric canal
Pyloric canal
Pylorus: thickened muscular portion forming sphincter between stomach and duodenum, located to the right of the midline at LV1 - LV2
What are the 2 notches present on the external stomach?
1) Cardiac: notch between junction of esophagus and fundus
2) Angular incisure: sharp angulation of lesser curvature at the junction of body and pyloric portion
What forms the pyloric sphincter?
Middle layer of smooth mm in the stomach wall: the inner circular layer
- the greatly thickened segment forms the pyloric sphincter
What are some prominent features of the internal mucosa of the stomach? What forms the gastric canal?
When the muscular layers are contracted the mucosa displays longitudinally oriented folds call rugae (Magenstrassen - stomach streets)
Located predominantly along the lesser curvature; forms gastric canal (temporarily visible during swallowing)
What does the anterior side of the stomach contact?
Anterior abdominal wall
Diaphragm
Left lobe of the liver
What does the superior side of the stomach contact?
diaphragm
What is the stomach bed?
Posteriorly and inferiorly, referred to as the stomach bed - area related to the stomach that directly ācradlesā it, including retroperitoneal structures behind the posterior wall of the omental bursa.
What 6 structures are found in the stomach bed?
a. Left hemidiaphragm
b. Spleen
c. Body and tail of pancreas
d. Superior pole of left kidney
e. Left suprarenal gland
f. Splenic artery
g. Transverse mesocolon
h. Left colic flexure
What is the largest single mass of lymphatic tissue in the body?
The spleen
Where is the spleen located? What mesentery is it associate with? What ribs?
Located in the left upper quadrant within the dorsal mesentery suspended between the greater curvature of the stomach and the diaphragm at ribs 9, 10, 11.
Is the spleen normally palpable? Why?
The spleen normally does not extend inferior to the costal margin and therefore is not palpable through the abdominal wall. (Needs to be at least 3X normal size to palpate: splenomegaly)
What is relative size, weight and shape of the spleen? (Probably a low yield card.)
- Normal weight range 100 250 gm (ave. 150 gm)
- Wedge shaped or tetrahedral, shape depending on:
- Distribution of vessels within
- Fullness of surrounding organs, i.e. stomach, transverse colon. - Surfaces
- Lateral surface: smooth and convex
- Medial surface: triangular and somewhat concave; location of hilum
- Note: Anterior border, between anterior and posterior surface is deeply notched
- Apex: directed superiorly and medialward
Base: inferior
What contacts the hilum of the spleen?
hilum is on medial surface, contact by tail of pancreas
What does the lateral surface of the spleen contact?
Lateral: contacts diaphragm inferior & medial to the costodiaphragmatic recess
What does the inferior surface of the spleen contact?
Inferior: base rests on phrenicocolic ligament (Sustentaculum lienis L. to prop, to hold upright)
What is the function of the duodenum?
Function: absorption of nutrients; site of openings of hepatopancreatic ducts for the addition of digestive enzymes and bile
How was the duodenum named?
Named for its length - approximately twelve finger breadths (25 cm)
What are the 4 parts of the duodenum, in order?
- Superior
- Descending
- Horizontal
- Ascending
What are the relationships of the duodenum to other structures in the abdomen?
1) Anterior: gallbladder and quadrate lobe of the liver
2) Posterior: common bile duct, gastroduodenal artery and portal vein
3) Superior: neck of the gallbladder and cystic duct
4) Inferior: head of the pancreas
Where does the second part of the duodenum go? What does it receive?
Descends anterior to the right lateral border of LV 1, 2, 3
Retroperitoneal
Receives the common bile duct and main pancreatic duct
What does the anterior portion of the descending duodenum contact?
right lobe of the liver, gall bladder, transverse colon and its mesocolon, coils of small intestine
What does the posterior portion of the descending duodenum contact?
hilum of the right kidney, right renal vessels, right ureter,right psoas major, IVC
What does the medial portion of the descending duodenum contact?
head of the pancreas, gastroduodenal a., common bile duct and main pancreatic duct
What is the level and compartment of the horizontal duodenum?
Runs horizontally from right to left across LV3
retroperitoneal
What does the anterior portion of the horizontal duodenum contact?
superior mesenteric vessels and coils of the small intestine and the root of the mesentery
What does the posterior portion of the horizontal duodenum contact?
psoas major, IVC, Aorta, right gonadal vessels and right ureter
What does the superior portion of the horizontal duodenum contact?
head of the pancreas
What is the course and level of the ascending portion of the duodenum?
Retroperitoneal (except for extreme terminal end)
Ascends along the left side of the aorta to LV2
Turns abruptly, becomes peritonealized and joins the jejunum
What ligament secures the duodenal-jejunal flexure?
The duodenal jejunal flexure is attached via a fibromuscular band, the suspensory muscle of the duodenum (Ligament of Treitz), to the posterior body wall in the area of the right crus of the diaphragm near the esophageal hiatus.
What does the anterior portion of the duodenum contact?
left side of the root of the mesentery and coils of small intestine
What does the posterior portion of the duodenum contact?
aorta, left gonadal vessels and left psoas
What does the medial portion of the duodenum contact?
head of the pancreas - uncinate process
What surface modifications of the duodenum increase surface area?
Villi - microscopic
Plica circularis - macroscopic circular folds of mucosa and submucosa (2nd -4th part)
Greater duodenal papila
What is the duodenal bulb?
Due to the lack of internal mucosal folds, the first part of the duodenum is thin- walled. Because of this it is easily visualized through the use of radiopaque material and therefore radiologists refer to this area as the duodenal bulb or cap.
What does the anterior duodenum contact?
1) Gall bladder (1st & 2nd portions)
2) Transverse mesocolon (2nd portion)
3) Superior mesenteric vessels (3rd portion)
What does the posterior duodenum contact?
1) Gastroduodenal artery (1st portion; second portion medially)
2) Common bile duct (1st portion; 2nd portion medially)
3) Hilum of right kidney (2nd portion)
4) Right ureter (2nd & 3rd portions)
5) IVC (2nd & 3rd portion)
6) Aorta (4th portion)
What does the exocrine portion of the pancreas do?
elaborates digestive enzymes secreted directly into the gut
What does the endocrine portion of the pancreas do?
elaborates hormones important in sugar metabolism (insulin, glucagon) which are secreted into the blood
What is the location of the pancreas? Is it retroperitoneal?
Except for tail, completely retroperitoneal (posterior to omental bursa)
Lies transversely across the posterior abdominal wall, from duodenum to spleen, posterior to the stomach (forms a significant portion of the stomach bed)
Where is the uncinate process of the pancreas? What vessels does it contact?
inferior hook shaped process which lies in contact posteriorly with the aorta and is crossed anteriorly by the superior mesenteric vessels
What structures does the anterior portion of the pancreatic head contact?
pylorus, transverse mesocolon, and coils of the small intestine
What structures does the posterior aspect of the pancreatic head contact?
grooved by the superior mesenteric vessels
What vessels contact the neck of the pancreas?
posterior - superior mesenteric vessels
vein receives the splenic vein, makes portal vein
What vessels frequently courses through the body of the pancreas?
Splenic artery
What portion of the pancreas is peritonealized?
The tail
What organ does the tail of the pancreas contact?
the spleen
- the hilum of the spleen
What 4 spatial relationships should you be aware of in regards to the anterior pancreas?
1) Stomach & pylorus
2) SMA & V over uncinate process
3) Transverse mesocolon
4) Small intestine
What 7 spatial relationships should you be aware of in regards to the posterior pancreas?
1) Common bile duct
2) IVC
3) Portal vein
4) Aorta
5) Right renal a. & renal vv.
6) Splenic a. & v.
7) LV 1, 2
What is the another name for the main pancreatic duct?
Duct of Wirsung
Where does the main pancreatic duct join the bile duct?
Joins the common bile duct at the hepatopancreatic ampulla
Where does the common bile duct join the duodenum?
Opens into the distal one third of the second portion of the duodenum via the greater duodenal papilla
What is an accessory pancreatic duct called? Where does it empty into the duodenum?
Called a duct of Santorini
It usually opens proximal to the greater duodenal papilla on the posterior wall of the second part of the duodenum via the lesser duodenal papilla.
Highly variable, present in ~15% of population
What is the largest gland in the body? What does it produce?
the liver
produces bile, stores nutrients, deaminates amino acids, detoxes crud, forms ammonia
Where is the porta hepatis? What passes through it? What is the attachment?
located at the center of the visceral surface
marks the entrance and exit of such structures as the hepatic arteries, portal vein, the hepatic bile ducts, nerves of the hepatic plexus and lymphatics of the liver
surrounded by the attachment of the lesser omentum
Where is the ligamentum teres hepatis/round ligament of the liver?
immediately to the left of the porta hepatis
