APC1

Question 1

What is the course of the oesophagus?

Answer 1

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

Question 2

What structures is oesophagus related to?

Answer 2

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.

Question 3

What contributes to the sphincteric action of the oesophago-gastric junction?

Answer 3

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

Question 4

What is the blood supply of the oesophagus?

Answer 4

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

Question 5

Where are the constrictions of the oesophagus?

Answer 5

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

Question 6

What is the nerve supply of the oesophagus?

Answer 6

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

Question 7

What does the abdominopelvic cavity consist of?

Answer 7

Abdomen proper and pelvic cavity

Continuous at pelvic inlet

Question 8

How is the abdomen divided into 9 regions?

Answer 8

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)

Question 9

Where does large intestine lie?

Answer 9

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

Question 10

Where do the liver, spleen and pancreas lie?

Answer 10

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

Question 11

What is the greater omentum?

Answer 11

Large, apron-like fatty fold lies anterior to small intestines, ultimately attached to PAW

Transverse colon attached to posterior surface

Question 12

What is the duodenojejunal flexure?

Answer 12

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

Question 13

What is the name of the junction between small and large intestine?

Answer 13

Ileocaecal junction

Question 14

What is the caecum?

Answer 14

Right iliac region - dilated portion of large intestine

Vermiform appendix near its apex

Question 15

What is the right colic flexure?

Answer 15

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

Question 16

What us the left colic flexure?

Answer 16

Splenic flexure

Transverse colon becomes continuous with descending colon

Question 17

What are retroperitoneal organs?

Answer 17

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

Question 18

What is the peritoneum?

Peritoneal cavity?

Answer 18

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

Question 19

What is peritoneal fluid?

Answer 19

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

Question 20

What is the dorsal mesogastrium?

Answer 20

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

Question 21

What occurs in the duodenum, ascending and descending and colon and rectum? (peritoneum)

Answer 21

They come to lie in contact with PAW, double layer of peritoneum is wholly or partially absorbed, leaving viscera with coating of peritoneum on their anterior or anterolateral surfaces only

Lower part of rectum and whole anal canal have no peritoneum associated

Question 22

What is the ventral mesogastrium?

Answer 22

Double layer of peritoneum derived from septum transversum (caudal foregut [stomach] region of embryo possess this)

Dorsal mesogastrium reflected on to PAW, ventral reflected onto AAW - stomach therefore completely suspended by peritoneum between the anterior and posterior walls

Question 23

Where do the spleen and liver develop?

Answer 23

Spleen: dorsal mesogastrium
Liver: vetral mesogastrium

Question 24

What are lines of peritoneal reflection?

Answer 24

Points at which double layers spread out to become continuous with parietal peritoneum

Question 25

Where is the stomach situated?

Answer 25

Empty - left hypochonrdium and epigastrium Varies in size, shape, position depending on volume of contents and posture and physique of individual Lies partly undercover of lower left ribs

Question 26

What are the two relatively fixed parts of the stomach?

Answer 26

Cardiac orifice - inferior to diaphragm where oesophagus joined Pyloric orifice - stomach continuous with duodenum, to right of midline at L1

Question 27

What are the curvatures of the stomach?

Answer 27

Lesser: cardiac orifice --> pylorus Angular notch on lowest part of lesser curvature (incisura angularis) - permanent feature of the stomach Greater: left of cardiac orifice --> over dome of fundus --> inferior part of pylorus

Question 28

What are the parts that the stomach is divided into?

Answer 28

Fundus: dome-shaped above cardiac orifice level (projects superiorly and left, below left dome of diaphragm) - in upright position usually full of gas -> X-ray identification Body: cardiac orifice level --> angular notch level Pyloric part = - proximal pyloric antrum - distal tubular pyloric canal or pylorus - surrounded by thick layer of circular smooth muscle - pyloric sphincter

Question 29

Describe peritoneum of the stomach (derivatives)

Answer 29

Continuous with derivatives of the ventral and dorsal mesogastria (embryonic mesenteries attach caudal foregut to anterior wall and PAW) 1) Part of VENTRAL mesogastrium which extended between lesser curvature and liver develops into LESSER OMENTUM 2) Part extended between liver and AAW develops into FALCIFORM LIGAMENT 3) DORSAL mesogastrium has three derivatives: greater omentum, GASTROSPLENIC ligament (greater curvature --> spleen) and LIENORENAL ligament (spleen ---> PAW)

Question 30

What are rugae?

Answer 30

Numerous folds in the interior of the stomach - occur due to folding of mucous membrane and underlying submucosa In life, mucous membrane is very vascular Four or five constant longitudinal rugae are normally present along the lesser curvature of the stomach Rugae seen elsewhere in stomach usually flatten out when stomach is distended

Question 31

What is the blood supply of the stomach derived from?

Answer 31

Celiac artery (artery of embryonic foregut, short, arises immediately below diaphragm at T12) Three branches: left gastric, splenic, common hepatic

Question 32

What is the left gastric artery?

Answer 32

Passes superiorly and left, across the PAW, to point where peritoneum is reflected from inferior surface of diaphragm on to oesophagus Gives branches to lower third of oesophagus Descends along lesser curvature, between layers of lesser omentum: supplies anterior & posterior surfaces of stomach by small branches

Question 33

What is the splenic artery?

Answer 33

Tortuous course across posterior abdominal wall to supply spleen (passes between two layers of lienorenal ligament) Runs along top of pancreas and supplies it After supplying spleen at hilum --> SHORT GASTRIC arteries and LEFT GASTROEPIPLOIC artery Short gastric arteries: supply fundus via gastrosplenic ligament Left gastroepiploic: along greater curvature (between two layers of greater omentum) - supplies anterior and posterior surfaces of stomach and GREATER OMENTUM by small branches

Question 34

What is the common hepatic artery?

Answer 34

Three branches: hepatic artery proper (supplying liver), RIGHT GASTRIC artery and GASTRODUODENAL artery Right gastric: between two layers of lesser omentum and ascends along lesser curvature to supply anterior and posterior surfaces by small branches - anastomoses with left gastric artery Gastroduodenal artery: passes posterior to superior (first) part of duodenum and gives rise to RIGHT GASTROEPIPLOIC and SUPERIOR PANCREATICODUODENAL arteries

Question 35

What are the branches of the gastroduodenal artery?

Answer 35

Right gastroepilploic: passes along greater curvature between two layers of greater omentum, supplying anterior and posterior surfaces of stomach and greater omentum by small branches - anastomoses with left gastroepiploic artery Superior pancreaticoduodenal: supplies head of pancreas and foregut region of duodenum (midgut part = superior mesenteric)

Question 36

Which arteries gain access to intraperitoneal stomach by using the retroperitoneal region of the duodenum as an entrance, then passing between layers of peritoneum (the omenta)

Answer 36

Right gastric | Right gastroepiploic

Question 37

What is the venous and lymphatic drainage of the stomach?

Answer 37

Venous via veins accompanying corresponding arteries --> directly into hepatic portal vein OR via one of its tributaries Four main groups of lymph nodes: LEFT GASTRIC, PYLORIC, PANCREATICOSPLENIC, RIGHT GASTROEPIPLOIC Lymph vessels runs with arteries of the stomach and drainage pattern similar to arterial distribution (but obviously flowing in other direction) All lymph eventually drains to celiac nodes around origin of celiac artery (as stomach = foregut structure)

Question 38

What is the sympathetic supply of the stomach? What is its function?

Answer 38

Fibres arise from segments T6-T9 and pass through diaphragm as the greater splanchnic nerves Synapse in celiac ganglia, within the celiac plexus Post-ganglionic fibres pass with blood vessels to stomach Efferents vasoconstict the gastric blood vessels, inhibit gastric musculature and secretory glands, stimulate the pyloric sphincter Afferent autonomic fibres primarily concered with pain travel with sympathetic pathways

Question 39

What is the parasympathetic supply of the stomach? What is its function?

Answer 39

Left and right vagus nerves become anterior and posterior vagal trunks as they pass through the diaphragm to supply stomach Anterior trunk and posterior trunk supplies anterior and posterior surface of stomach by number of smaller branches - Some branches contribute to the celiac plexus (prevertebral autonomic plexus found at origin of celiac artery) Vagal fibres stimulate gastric secretion, contraction of gastric musculature, relaxation of the pyloric sphincter Hepatic branches derived from both vagal trunks and pass between layers of lesser omentum to join hepatic plexus Afferent fibres travelling within the vagus concerned with reflex activity in response to mechanical and metabolic stimuli

Question 40

Describe stomach surface anatomy

Answer 40

Cardiac orifice behind 7th costal cartilage (left of midline) Pyloric orifice on transpyloric plane (right of midline) Highest point of fundus = 5th intercostal space Greater curvature extends downwards and left as fat as 10th costal cartilage, before turning medially to reach pylorus Lowest part of the curving path of lesser curvature marked by angular notch (incisura angularis), which lies just left of the midline

Question 41

Where does the duodenum lie?

Answer 41

Commences at pyloroduodenal junction to right of midline at about L1 - lies in epigastric and umbilical regions Mostly retroperitoneal therefore relatively fixed in position In direct contact with PAW

Question 42

What is the first part of the duodenum? What is it in contact with?

Answer 42

1st = Superior part Starts at pylorus and passes posterosuperiorly to right under cover of the liver and gallbladder Proximal portion not retroperitoneal but enclosed by lesser omentum Remainder is retroperitoneal Bile duct, gastroduodenal artery and hepatic portal vein pass behind the retroperitoneal portion

Question 43

What is the second part of the duodenum? What is it in contact with?

Answer 43

2nd = descending Arches around head of pancreas Entirely retroperitoneal and separated by loose CT from the fat and fascia covering the hilar region of the right kidney BILE duct opens with MAIN PANCREATIC duct into posteromedial aspect, at MAJOR DUODENAL PAPILLA - marks the junction between embryonic foregut and MIDGUT Sometimes an accessory pancreatic duct opens into the duodenum proximal to the major papilla at the MINOR PAPILLA

Question 44

What is the third part of the duodenum? What is it in contact with?

Answer 44

3rd = horiztonal Completely retroperitoneal Passess transversely across PAW at about L3 Superior mesenteric vessels cross anterior surface

Question 45

What is the fourth part of the duodenum? What is it in contact with?

Answer 45

4th = ascending Passess superiorly to level of L2, anteriorly and to the left of the aorta At duodenaljejunal flexure the duodenum bends anteriorly, and is continuous with the jejunum - hence the flexure marks the start of the intraperitoneal jejunum

Question 46

How does the duodenum appear in a radiograph using fluid containing barium salts? Why?

Answer 46

First part = smooth area called duodenal cap | Remainder - barium broken up by the PLICAE CIRCULARES, giving it an irregular appearance

Question 47

Radiological appearance of carcinoma and peptic ulcer?

Answer 47

??

Question 48

Describe the interior of the duodenum | How can it be visualised?

Answer 48

Mucous membrane is thick First part smooth but remainder thrown into numerous circular folds - the plicae circularis - functional significance = villi and microvilli to increase surface area for absorption Visualised by endoscope or indirectly using radiography (ingest radio-opaque medium - barium salts = barium meal)

Question 49

What is the blood supply to the duodenum?

Answer 49

Proximal duodenum (originates from foregut) receives blood from the celiac artery, distal duodenum (originates the midgut)= superior mesenteric artery Gastroduodenal artery ---> SUPERIOR PANCREATICODUODENAL artery - supplies proximal Part of duodenum distal to major duodenal papilla supplied by INFERIOR PANCREATICODUODENAL artery (branch of superior mesenteric) (Pancreaticoduodenal arteries are very small - don't need to identify them)

Question 50

What is the venous drainage of the duodenum?

Answer 50

Drainage via SUPERIOR MESENTERIC, SPLENIC veins or directly into HEPATIC PORTAL vein (note: no gastroduodenal vein)

Question 51

What is the lymphatic drainage of the duodenum?

Answer 51

Lymphatic vessels follow the arteries Anterior vessels drain into PANCREATICODUODENAL nodes of the SUPERIOR and INFERIOR PANCREATICODUODENAL ARTERIES - Then drains to PYLORIC nodes of the GASTRODUODENAL artery, then CELIAC nodes Posterior vessels drain directly into SUPERIOR MESENTERIC nodes

Question 52

Surface anatomy of duodenum?

Answer 52

- Retroperitoneal structure - position relatively fixed - Lies in epigastric and umbilical regions - Surface markings can be projected onto anterior abdominal wall (vertebral levels and costal cartilages) 1st: commences at pyloroduodenal junction to right of midline at about L1 (8th costal cartilage?) 2nd: (down past 10th costal cartilage?) 3rd: passes transversely across PAW at about L3 4th: passes superiorly to level of L2, anteriorly and to the left of the aorta (about 9th costal cartilage?)