Lecture 4 - Abdominal Viscera I Flashcards
2 parts of mouth in the digestive tract?
- Oral cavity
2. Pharynx
Esophagus region of abdomen?
Epigastric
How does the esophagus enter the abdomen? Vertebral level?
Through right crus of diaphragm at T10
Name of portion of stomach where esophagus enters? Location with regards to midline?
Cardial orifice of stomach, left of midline
Function of esophagus?
Connects pharynx to stomach
Vertebral levels of esophagus?
C6 to T11
Position of esophagus with regards to the midline?
Anterior aspect of vertebrae in midline => anterior and to the left laterally to be anterior to the thoracic aorta to enter the diaphragm
At what 4 locations can the esophagus be compressed/narrowed? What is at higher risk at these locations?
- Junction of esophagus and pharynx in the neck
- Aortic arch crossing over the esophagus in superior mediastinum
- Left main bronchus crossing over the esophagus in posterior mediastinum
- At esophageal hiatus in posterior mediastinum
Higher risk of swallowed objects getting lodged at these locations and if the object is corrosive it would cause more damage at these locations
Where do esophageal ruptures occur typically? Treatment?
Lower third of esophagus on the left
Treatment: urgent surgical repair
Only part of posterior mediastinum that lymphatically drains to abdomen?
Inferior 1/3rd of esophagus
What do we call the vagus nerves right before they become the anterior and posterior trunks on the esophagus?
Right and left vagal trunks
7 structures of the adult foregut?
- Esophagus (distal end)
- Stomach
- Duodenum (proximal half)
- Liver
- Gallbladder
- Pancreas
- Spleen
8 structures of the adult midgut?
- Duodenum (distal half)
- Jejunum
- Ileum
- Cecum
- Appendix
- Ascending colon
- Hepatic flexure of colon
- Transverse colon (proximal two-thirds)
5 structures of the adult hindgut?
- Distal third of the transverse colon
- Splenic flexure of colon
- Descending colon
- Sigmoid colon
- Rectum
Describe the surgical procedure of esophageal resection to treat cancer. What is this called?
Transthoracic esophagectomy:
- Patient is placed in supine position
- Laparotomy (surgical incision of abdomen) to assess evidence of disease in abdominal cavity
- Stomach is mobilized with preservation of right gastric and gastro-omental arteries
- Short gastric vessels and left gastric vessels are divided
- Pyloromyotomy is performed (incision in stomach on the pylorus, the furthest part of the stomach that connects to the duodenum)
- Abdominal wound is closed
- Patient is placed in left lateral position
- Right posterolateral thoracotomy is performed through 5TH INTERCOSTAL SPACE
- Azygos vein divided to provide full access to the whole length of the esophagus
- Stomach is delivered through the diaphragmatic hiatus
- Esophagus is resected and stomach is anastomosed to the cervical esophagus
How does esophageal cancer spread?
Submucosa or locoregional lymph nodes
When are most esophageal cancers diagnosed? Survival rate?
Late
Survival rate: 25% 5-year survival rate
What is the right side of the esophagus covered by?
Mediastinal pleura of right lung
Position of thoracic duct in regards to esophagus in posterior mediastinum?
- Inferior portion: right side
- Superior portion: left side
4 structures that are posterior to the esophagus at some point in the posterior mediastinum?
- Thoracic duct
- Hemiazygos veins
- Right posterior intercostal arteries
- Thoracic aorta (near diaphragm)
5 structures that are anterior to the esophagus at some point in the posterior mediastinum?
- Trachea
- Right pulmonary artery
- Left main bronchus
- LA
- Aortic arch
What arteries do esophageal arteries arise from? Where does each originate from?
CERVICAL segment:
1. Inferior thyroid arteries from thyrocervical trunks which come from the subclavian arteries
THORACIC segment:
2. Thoracic aorta
3. Right bronchial arteries
4. Right posterior intercostal arteries from thoracic aorta
ABDOMINAL segment:
5. Left gastric artery from celiac trunk MAINLY
6. Short gastric artery from splenic artery
7. Left inferior phrenic artery from abdominal aorta
What veins do esophageal veins drain into?
CERVICAL segment: 1. Inferior thyroid vein THORACIC segment: 2. Azygos vein 3. Hemiazygos vein 4. Accessory hemiazygos vein ABDOMINAL segment: portal system through: 5. Left gastric vein 6. Short gastric vein
Lymphatic drainage of esophagus? 9 types of nodes.
- Internal jugular lymph nodes
- Lower internal jugular lymph nodes
- Tracheal lymph nodes
- Tracheabroncheal lymph nodes
- Retrocardiac lymph nodes
- Infracardiac lymph nodes
- Posterior mediastinal lymph nodes
- Diaphragmatic lymph nodes
- Left gastric lymph nodes (inferior 1/3rd)
Innervation of esophagus?
Branches from vagus nerves and sympathetic trunks
Innervation of striated muscle in superior portion of the esophagus?
Branchial efferents from vagus nerves
Innervation of smooth muscle fibers in inferior portion of the esophagus?
Preganglionic fibers that are parasympathetic visceral efferents and synapse in the myenteric and submucosal plexuses of the enteric NS in the esophageal wall
Sensory innervation of esophagus? Which ones are responsible for transmitting pain information to the CNS?
Visceral afferents in :
- Vagus nerves
- Sympathetic trunks***
- Splanchnic nerves***
Are the visceral afferents from the vagus nerves involved in the relay of pain recognition?
NOPE
What are the 2 trunks formed by the esophageal plexus?
Trunks formed by the esophageal plexus just above the diaphragm:
- Anterior vagal trunk on anterior surface of esophagus mainly from fibers from left vagus nerve forming several smaller trunks
- Posterior vagal trunk on posterior surface of esophagus mainly from fibers from right vagus nerve forming a single trunk
These continue through the diaphragm
Are glands, liver, and pancreas embryological outgrowths of the digestive tract?
YUP
Describe the strength of the lower esophageal sphincter compared to the pyloric sphincter or sphincter of Oddi. Clinical significance?
WEAK, but the esophageal hiatus provides some additional strength
If the stomach is herniated through the esophageal hiatus, this extra support is lacking and the patient will experience GERD
What is the eaten apple sign?
Esophageal cancer on a CXR
What does the lining of the stomach form when it is empty?
Folds = rugae
Volume the stomach can hold?
~1/2 gallon
Effect of HCl on meat?
Softens connective tissue
What is the most dilated portion of the GIT?
Stomach
Regions of abdomen that stomach occupies?
- Epigastric
- Left hypochondrium
- Umbilical
4 regions of stomach? Describe each.
- The cardia, which surrounds the opening of the esophagus into the stomach
- The fundus of the stomach, which is the area above the level of the cardial orifice below the diaphragm
- The body of the stomach, which is the largest region of the stomach
- The pyloric part, which is divided into the pyloric antrum and pyloric canal and is the distal end of the stomach
What is the pyloric constriction?
External mark of pylorus on stomach
2 parts of pylorus?
- Pyloric sphincter
2. Pyloric orifice
Surface anatomy of pyloric orifice?
Just to the right of midline in transpyloric plane (L1)
What attaches to the greater curvature of stomach?
Point of attachment for the gastrosplenic ligament, the greater omentum, the gastrocolic ligament, and the gastrophrenic ligament
What attaches to the lesser curvature of stomach?
Point of attachment for the lesser omentum
What is the cardial notch of the stomach?
Superior angle created when the esophagus enters the stomach between esophagus and fundus of stomach
What is the angular incisure/notch of the stomach?
A bend on the lesser curvature where the body and pyloric antrum meet
What is the greater curvature of the stomach?
Longer, convex border
What is the lesser curvature of the stomach?
Shorter, concave border
Blood supply of stomach? Where does each arise from?
- Right gastric artery – variable in origin – usually branches off hepatic artery proper
- Left gastric artery – arises directly from celiac trunk
- Right gastroepiploic artery – 1 of 2 terminal branches of gastroduodenal artery
- Left gastroepiploic artery – arises from splenic artery
- Short gastric arteries (4-5) – arise from splenic artery (FUNDUS)
- Posterior gastric artery – arises from splenic artery BUT not always present
Other name for right/left gastroepiploic artery?
Right/left gastro-omental artery
Lymphatic drainage of stomach?
Celiac lymph nodes since follows arteries to stomach, which all branch directly or indirectly from the celiac trunk
3 structures located anterior to the stomach?
- Left liver lobe
- Anterior body wall
- Diaphragm
2 structures located posterior to the stomach?
- Pancreas
2. Spleen
Arteries along lesser curvature of stomach?
Right and left gastric arteries
Arteries along greater curvature of stomach?
Right and left gastro-omental arteries
What is a trichobezoar?
Hair stuck in the stomach
Changes in diameter of small intestine throughout its course?
Narrowing
Beginning and end of duodenum?
- Beginning: pylorus
2. End: duodenojejunal junction
Vertebral levels of duodenum? What does this correspond to?
L1 to L3
L1 is halfway between jugular notch and pubic area
4 parts of duodenum? Describe each along with their vertebral level. Which one is the longest?
- The superior part (L1): extends from the pyloric orifice of the stomach to the neck of the gallbladder, is just to the right of the body of vertebra L1, mostly horizontal
- The descending part (L2/L3): curves around head of pancreas, just to the right of midline and extends from the neck of the gallbladder to the lower border of vertebra L3
- The inferior part (L3)=horizontal part: longest section, crossing the IVC, the aorta, and the vertebral column
- The ascending part (L2/L3): upward on, or to the left of, the aorta to approximately the upper border of vertebra L2 and terminates at the duodenojejunal flexure
Overall shape of duodenum?
C shaped
Where do most duodenal ulcers occur?
Superior first part of it
2 other names for superior part of duodenum?
The ampulla or duodenal cap
5 structures posterior to duodenum?
- Bile duct
- Gastroduodenal artery
- Portal vein
- IVC
- Right kidney
What is the major duodenal papilla?
Common entrance for the bile and pancreatic ducts in the descending part of the duodenum
What passes the anterior surface of the descending part of the duodenum?
Transverse colon
What is the minor duodenal papilla? Where is it located with regards to the major duodenal papilla?
Entrance for the accessory pancreatic duct
Just above the major duodenal papilla
Location of right kidney with regards to duodenum?
Posterior to descending part of duodenum
What 2 structures pass anteriorly to the horizontal part of the duodenum?
- Superior mesenteric artery
2. Superior mesenteric vein.
Other name for horizontal part of duodenum?
Inferior part