APC1 Flashcards
What is the course of the oesophagus?
Begins C6, continuous with laryngopharynx
Lies in superior and posterior mediastina
Enters abdomen at T10 through muscular part of diaphragm (left of midline) - sling of muscle originating from right crus encircles oesophagus at this point
Short intra-abdominal course before entering stomach
What structures is oesophagus related to?
Anteriorly - the posterior surface of the liver
Posteriorly - left crus of the diaphragm
Closely related to descending aorta – first on its right side, and then in front of it.
Enters thorax slightly left of median plane, more left as it descends - around T7, begins to pass from medial side of descending aorta to front of it;
Oesophagus even more left than the aorta before it pierces the diaphragm.
What contributes to the sphincteric action of the oesophago-gastric junction?
Sling of muscle from right crus
Short intra-abdominal course
Tone in smooth muscle of oesophageal wall
Flap of mucous membrane where oesophagus and stomach meet
Folds of mucous membrane at lower end of oesophagus
What is the blood supply of the oesophagus?
Upper third: inferior thyroid artery and veins, deep cervical nodes
Middle third: branches from thoracic aorta, azygos system, superior and posterior mediastinal nodes
Lower third: branches from left gastric artery, left gastric vein (tributary of portal vein), nodes along left gastric artery –> coeliac nodes at origin of celiac artery
Where are the constrictions of the oesophagus?
Through cricopharyngeus
Posterior to arch of aorta and left primary bronchus
Through the diaphragm
These are sites where foreign bodies can lodge, and can be difficult to pass esophagoscope
Strictures form here after drinking caustic substances as delay in moving substances
What is the nerve supply of the oesophagus?
Sympathetic: sympathetic trunk and splanchnic nerves
Parasympathetic: vagus nerves branch and contribute to oesophageal plexus on its anterior surface
Left vagus nerve becomes anterior vagal trunk, right vagus nerve becomes posterior vagal trunk
Recurrent laryngeal nerves (branches from the vagus nerve) supply upper part of oesophagus
What does the abdominopelvic cavity consist of?
Abdomen proper and pelvic cavity
Continuous at pelvic inlet
How is the abdomen divided into 9 regions?
Upper horizontal plane: TRANSPYLORIC
(1/2 between jugular notch and upper border pubic symphsis, lower border L1)
or SUBCOSTAL
(10th costal margin + L3 body)
Lower horizontal = TRANSTUBERCULAR
(L5, through iliac tubercles)
Vertical = MIDCLAVICULAR
(mid clavicle –> midway between ASIS and pubic tubercle)
Where does large intestine lie?
Ascending colon: lies on PAW mainly in right lumbar region
Descending colon: similar position, left lumbar
Transverse: suspended from PAW via peritoneum, traverses abdomen - hangs down into umbilical region or even lower
Sigmoid: left iliac region (fossa) and hypogastric region
Where do the liver, spleen and pancreas lie?
Liver: right hypochondrium, epigastric, part of left hypochondrium
Spleen: left hypochondrium beneath left dome of diaphragm - outer convex surface is separated from the posterior parts of the 9-11th ribs by the diaphragm and costodiaphragmatic recess of the pleural cavity
Pancreas: within C loop of duodenum and lies with axis directed from right to left, towards spleen
What is the greater omentum?
Large, apron-like fatty fold lies anterior to small intestines, ultimately attached to PAW
Transverse colon attached to posterior surface
What is the duodenojejunal flexure?
Point where small intestine disappears behind PAW (follow it all the way up) - where C shape of duodenum becomes jejunum (retroperitoneal duodenum –> intraperitoneal jejunum)
Jejenum comes forward as is wrapped in peritoneum
What is the name of the junction between small and large intestine?
Ileocaecal junction
What is the caecum?
Right iliac region - dilated portion of large intestine
Vermiform appendix near its apex
What is the right colic flexure?
Hepatic flexure
Point where: ascending colon (right lumbar region) becomes is continuous with transverse colon
Right colic (hepatic) flexure
adjacent to liver
right kidney lies posteriorly
What us the left colic flexure?
Splenic flexure
Transverse colon becomes continuous with descending colon
What are retroperitoneal organs?
S: suprarenal (adrenal) gland A: aorta/IVC D: duodenum (second and third part) P: pancreas (except tail) U: ureters C: colon (ascending and descending - not caecum) K: kidneys E: (o)esophagus R: rectum
What is the peritoneum?
Peritoneal cavity?
Serous membrane, lines walls of APC and invests abdominopelvic organs
Cavity: space between adjacent serous surfaces of peritoneum (doesn’t contain organs) &contains small amount of peritoneal fluid
- closed sac in male
- in female - open to exterior due to arrangement of ovaries and fallopian tubes
What is peritoneal fluid?
Small volume of fluid within peritoneal cavity derived from tissue fluid (therefore plasma)
Fairly rapid turnover of fluid which is absorbed by peritoneal cells
Provides lubrication so that mobile abdominal viscera may move freely
What is the dorsal mesogastrium?
Double layer of peritoneum - suspends gut tube from posterior wall in the embryo
Stomach, small intestine and parts of large intestine retain this
Adult: completely invested by peritoneum and suspended away from the posterior abdominal wall by double layer of peritoneum