Abdomen Anatomy Flashcards
What structure pierces the buccinator muscle?
Stensen’s (parotid) duct
Name the bones that make the hard palate?
Maxillary bone (anteriorly) Palatine bone (posteriorly)
The soft palate (uvulae) has 5 muscles. 4 of which are innervated by the vagus nerve what is the only muscle of the soft palate not innervated by the vagus nerve?
Tensor veli palatini muscle – Trigeminal nerve
What is the function of the tensor veli palatini?
Tenses the soft palate, flattens it and prevents food from entering the nasal cavity. (Tensor = tense, Veli = veil, Palatini = palate)
The tongue is divided into the anterior 2/3 and the posterior 1/3 by the ‘V’ shaped terminal sulcus. The foramen caecum lies at its apex. What is the embryological significance of this structure?
This was the site at which the embryonic thyroid gland originated before descending down into the neck. In some individuals, the duct connecting the duct to the thyroid (thyroglossal duct) does not obliterate
What nerve supplies the motor innervation to the tongue?
Hypoglossal nerve (CNXII)
What nerve gives the general + special sensation to the posterior 1/3 of the tongue?
Glossopharyngeal nerve (CNIX)
What nerve gives the general sensation to the anterior 2/3 of the tongue?
Trigeminal nerve (Specifically the lingual branch of V3)
What nerve gives the special (taste) sensation to the anterior 2/3 of the tongue?
Chorda tympani branch of the facial nerve (CNVII)
Name the 3 salivary glands?
Parotid, submandibular, and sublingual
Name the 3 structures travelling through the parotid gland?
1) External carotid artery 2) Facial nerve 3) Retromandibular vein
What is the innervation of the parotid gland?
Glossopharyngeal nerve (NOT FACIAL)
What are the 4 parasympathetic cranial nerves?
3 (Oculomotor), 7 (Facial), 9 (Glossopharyngeal), and 10 (Vagus)
What is the innervation of the submandibular and sublingual glands?
Facial nerve
The Parotid (Stensen’s) duct will pierce the buccinator and enter the oral cavity at what location?
Adjacent to upper second molar
What are the 3 divisions of the pharynx?
Nasopharynx, Oropharynx, Laryngopharynx
What are the borders of the nasopharynx?
Base of skull (Choanae) 🡪 Soft palate
What are the borders of the oropharynx?
Soft palate 🡪 Epiglottis
What are the borders of the laryngopharynx?
Epiglottis 🡪 Cricoid cartilage (C6)
What structure lies in the most posterior aspect of the nasopharynx and what structure does it sit close to?
Adenoids (pharyngeal tonsil)
Opening of the eustachian tube
What is the clinical correlate of the relationship between the adenoids and eustachian tube?
Enlarged adenoids can compress opening of the eustachian tube -> middle ear infection
What gives the sensory innervation to the nasopharynx?
Maxillary nerve (V2 of trigeminal nerve)
What two folds (of muscle) sit anterior and posterior to the palatine tonsil?
Palatopharyngeus (Sitting posterior, closer to the pharynx) and Palatoglossus (Sit anterior, closer to the glossus or tongue)
What is the sensory innervation of the oropharynx?
Glossopharyngeal nerve
What is the sensory innervation of the laryngopharynx?
Vagus nerve
What is the valleculae?
This is a space that sits anterior to the epiglottis – it is clinically relevant as food and foreign bodies can get caught here
What are the 4 constrictions of the oesophagus?
Importance of these constrictions?
As it crosses the: Arch of aorta, Left main Bronchus, Cricoid cartilage + Diaphragm (ABCD)
Most likely sites for a bolus of food to become trapped
Which part of the stomach is guarded by the lower oesophageal sphincter?
Cardia
Damage to the lower oesophageal sphincter predisposes you to which condition?
GORD 🡪 Barrett’s oesophagus
What is the pathophysiology behind Barrett’s oesophagus?
Reflux of gastric acid contents leads to metaplasia where the usual stratified squamous epithelium is replaced by the columnar epithelium you would usually see in the stomach. In about 10% of the patients with Barrett’s oesophagus, Dysplasia occurs (leading to oesophageal cancer)
The final portion of the stomach is named the pylorus and it controls the emptying of gastric contents into the duodenum. How may you get malfunctioning of the pyloric sphincter?
Hypertrophy of the Pyloric sphincter leading to pyloric stenosis. Seen in paediatrics with the classic ‘projectile vomiting’ and the ‘olive shaped mass’ on abdominal palpation
Which part of the duodenum is the only part to be intraperitoneal?
First (superior) part. Parts 2-4 are retroperitoneal
On the second part of the duodenum we find the major and minor duodenal papillae. What structures open up here?
Major duodenal papillae – Ampulla of Vater/Hepatopancreatic ampulla.
Minor duodenal papillae – accessory pancreatic duct
The Ampulla of vater/Major duodenal papillae marks the beginning of which portion of the gut?
Midgut
What is the blood supply to the uncinate process + head of the pancreas?
Pancreatoduodenal artery 🡪 gastroduodenal 🡪 common hepatic N.B the pancreatoduodenal A can also be subdivided into the anterior + posterior divisions with the posterior division coming off the SMA. This is beyond the scope of the session.
What is the blood supply of the neck body and tail of the pancreas?
Splenic artery
Most duodenal ulcers occur posteriorly (95%) and can often lead to haemorrhage. The reason for this is that they can erode into a blood vessel that runs posteriorly to the duodenum. Name this artery?
Gastroduodenal artery
At what vertebral level does the Coeliac trunk (the blood supply to the foregut) come off of the abdominal aorta?
T12
What are the 3 branches of the coeliac trunk?
1) Common Hepatic 2) Left gastric 3) Splenic
What is the sympathetic innervation to the stomach and foregut?
Greater splanchnic nerve (T5-T9)
How does the rotation of the stomach affect the position of where the left and right vagus nerve sits?
As the stomach rotates over to the right-hand side of the body 🡪 Left vagus nerve sits anteriorly to the stomach, right vagus nerve sits posteriorly to the stomach
Which lobe of the liver sits adjacent to the gallbladder?
Quadrate lobe
The liver develops within what structure?
Ventral mesogastrium
Which ligament separates the right and left lobe of the liver?
Falciform ligament
The falciform ligament continues as what structure?
Ligamentum teres (round ligament)
What was the round ligamentum embryological remanent?
Umbilical vein
The ligamentum venosum is adjacent to the caudate lobe of the liver. What was the name of this structure during embryonic development?
Ductus venosum
What was the function of the Ductus venosum?
A vessel that connected the umbilical vein to the IVC. This allows the venous circulation to bypass the hepatic circulation and go straight to the IVC
Name the portal triad?
Proper Hepatic Artery, Common Bile duct, Hepatic portal vein
Name the two portions of the lesser omentum?
Hepatogastric ligament + Hepatoduodenal ligament
What runs within the free edge of the lesser omentum (aka the hepatoduodenal ligament)?
Portal triad
What manoeuvre can be used to interrupt the blood flow to the liver when operating on it?
Pringle’s manoeuvre – Place a clamp over the hepatoduodenal ligament
What two arteries provide the blood supply to the liver + include the contributions?
1) Hepatic portal vein (75%) 2) Hepatic artery (25%)
What veins unite to form the hepatic portal vein?
Splenic vein + Superior mesenteric vein
Recall that a surgeon’s fingers can be passed behind the lesser omentum. As you insert your digit you need to pass through a foramen (or opening) called the Epiploid/Omental foramen. State the boundaries of the epiploic foramen?
Roof: Caudate lobe of the liver. Floor: Duodenum (1st part). Posterior border: IVC. Anterior border: Hepatoduodenal ligament
What organ is attached onto the posterior layer of the greater omentum?
Transverse colon
Why is it referred to as the abdominal policeman?
It can wrap around areas of inflammation, limiting infection spread. N.B The downside of this is that it provides the perfect route for cancers to spread through the abdomen
What is the embryological remnant of the median umbilical ligament?
Urachus. The median umbilical ligament attaches from the anterior surface of the bladder (apex) to the umbilicus. In utero it was the urachus and functioned to empty the foetal bladder
What is the embryological remnant of the median umbilical fold?
Umbilical artery
What travels within the lateral umbilical fold?
Inferior epigastric vessels
Which part of the pancreas is intraperitoneal?
Tail
What is the relationship between the SMA/SMV and the uncinate process?
The vessels run anterior to the uncinate.
What vessel supplies the neck, body, and tail of the pancreas?
Splenic artery
The common bile duct arises from what two structures?
Common hepatic duct + cystic duct
Where does the spleen develop embryologically?
Dorsal mesogastrium
Between which ribs does the spleen lie?
9th – 11th
What is the difference between an Omphalocele and Gastroschisis?
Omphalocele – viscera fails to retract back and lies outside of the abdominal wall but is covered in peritoneum. Gastroschisis: intestines extend through abdominal wall + not covered in peritoneum
What is the ligament of Treitz and why is it clinically important?
Ligament of Treitz goes from Duodenal jejunal flexure 🡪 Underside of the diaphragm. It is used to demarcate an upper from a lower GI bleed
What structure is found on the inside of the jejunum and ileum to provide surface area to the bowel?
Plicae circularis
The arterial arcades and vasa recta are vessels that come off the SMA (travelling within the mesentery) that lie close to the bowel. Describe the appearance of the Arcades and vasa recta in the jejunum?
Few arterial arcades, long vasa recta
Describe the appearance of the arterial arcades and vasa recta in the ileum?
More arcades, short vasa recta
Peyer’s patches are the resident immune cell in the gut – are they seen in the jejunum or ileum most commonly?
Ileum
What is a Meckel’s diverticulum?
Failure of the vitelline duct (a congenital duct connection the embryonic gut to the umbilicus) to obliterate
What is it called when one piece of bowel slips inside or ‘telescopes inside’ another piece of bowel?
Intussusception
Inguinal hernias are more common in which sex?
Males – 20x more common, due to the descent of the testes through the inguinal canal.
What structure prevents backflow of gut contents from the caecum to the small bowel?
Ileocaecal valve
The appendix comes off the caecum. What is the most common lie of the appendix?
Retrocaecal
The appendicular artery supplies the appendix. From which artery does it arise?
Ileocolic artery 🡪 From SMA (as it is midgut)
Where is McBurney’s point?
Location that classically corresponds to the location of the appendix. Lies in the Lateral 1/3 between the ASIS and umbilicus
What is the blood supply of the ascending colon?
Right Colic Artery 🡪 SMA
Where does the midgut transition into the hindgut?
Two-thirds distally along the transverse colon
What are the main branches of the SMA?
Jejunal + ileal arteries, Ileocolic artery, Middle Colic + right colic artery
Where does the lymphatic drainage of the midgut go?
Cisterna Chyli (a dilated sac that collects lymph from the abdomen before draining into the thoracic duct)
At what vertebral level do you find the cisterna chyli?
L1
What is the sympathetic supply to the midgut?
Lesser thoracic splanchnic nerve
What is the parasympathetic supply to the midgut?
Vagus nerve
What is the classic pattern of pain seen in appendicitis?
Initially begins as umbilical pain 🡪 later radiates to the right iliac fossa (due to concept of referred pain)
What are the 3 gross morphological features that you see in the large bowel that you do not see in the small bowel?
- Haustra (the sacculated appearance of the bowel) 2. Taeniae Coli – 3 longitudinal bands of muscle that run across the bowel 3. Omental/epiploic appendages – tags of peritoneum filled with fat
What is diverticular disease?
An outpouching of the mucosa of the colon. If this outpouching gets inflamed we get diverticulitis
What two features of the rectum are designed to maintain continence?
- Transverse rectal folds (thickenings of the circular muscle in the rectal wall) 2. Ampulla (distal portion of the rectum that is dilated)
The peritoneum is reflected from the rectum onto the uterus (female) and bladder (men). What do we call these reflections?
Rectovesical pouch (men) + rectouterine pouch (women)
Where does the hindgut formally end?
Dentate/Pectinate line
What type of epithelium lies above and below the dentate line?
Columnar above (as above is the rectum (gut) and Stratified squamous below (as it is the anus below)
What is the arterial supply above the dentate line?
Superior rectal artery 🡪 IMA (Hindgut)
What is the arterial (+ venous) supply below the dentate line?
Middle and inferior rectal artery
What is the marginal artery of Drummond?
An artery that comes off the IMA and travels to the splenic flexure where it supplies the ‘watershed’ area where the foregut circulation (SMA) meets the hindgut (IMA) circulation. It will anastomose with the SMA and act as a collateral supply if one of these arteries was to be blocked.
What is the parasympathetic supply of the hindgut?
Pelvic splanchnic nerve (S2-S4). Remember parasympathetic outflow is cranial and sacral. Sympathetic is thoracolumbar.
What is the sympathetic supply to the hindgut?
Lumbar splanchnic nerve
When we have patients with cirrhosis the scarring obstructs blood flow going through the liver. In turn we develop portal hypertension which causes blood to back up through the portal circulation. What signs may we see as a result of this?
- Splenomegaly (blood backs up into the splenic vein) 2. Oesophageal varices (due to dilation of gastric veins) 3. Anorectal varices (dilation of superior rectal veins) 4. Caput medusa (epigastric vein dilation)
In which type of Jaundice (pre-hepatic, hepatic, post-hepatic) do you develop pale stools and dark urine?
Post-hepatic
Explain the above phenomenon?
Bilirubin gives the pigment to the urine (yellow) and stool (brown). When a stone obstructs the biliary tree it prevents bilirubin from entering the duodenum and the rest of the gut 🡪 pale stools. As this bilirubin sits in the biliary tree behind the stone it is eventually absorbed into the bloodstream 🡪 into the glomerulus 🡪 filtered out from the kidney into the urine causing dark urine
What do we call a condition where you have a stone in the cystic duct/gallbladder that leads to inflammation due to superimposed infection?
Acute Cholecystitis
What sign is positive in acute cholecystitis?
Murphy’s sign
Cancer of the pancreatic head can cause what sign involving the biliary system?
Obstructive jaundice due to compression of the biliary tree
Where would you begin palpation for an enlarged spleen?
Right iliac fossa
What vertebral levels do the kidneys lie at?
T12-L3
What structures enter the hilum of the kidney going from anterior to posterior?
Renal Vein, Renal Artery, Renal Pelvis
What do we call the outermost portion of the renal parenchyma?
Renal cortex (medulla forms the inner aspect)
At what level does the renal artery come off the abdominal aorta?
L1
What do we call the first branching vessels off the renal arteries?
Segmental arteries
What are the vessels supplying the kidney after the segmental arteries?
Lobar arteries
What epithelium lines the ureter?
Stratified transitional epithelium
The ureter passes over which muscle?
Psoas major
In males what does the ureter pass underneath?
Vas deferens
In females what does the ureter pass underneath?
Uterine artery
What are the retroperitoneal structures?
SADPUCKER Organs: Suprarenal gland, Aorta/IVC, Duodenum (2-4), Pancreas (except tail), Ureter, Colon (ascending/descending), Kidney, Oesophagus, Rectum
What are the 3 anatomical constrictions of the ureter?
- Ureteropelvic junction (where renal pelvis becomes the ureter) 2. Where ureter crosses the external iliac artery 3. Ureterovesical junction (where the ureter enters the bladder)
What is the clinical significance of these constrictions?
Most likely sites of renal stone formation and obstruction
What form of imaging is most appropriate for renal stones?
Non-Contrast CT KUB (Kidney, ureter, bladder) – contrast appears as white on a CT. This would be the same colour as a potential stone making it difficult to appreciate the presence of one.
What is the classic pattern of pain associated with renal stones?
Loin to groin pain
What is the blood supply to the ureter?
- Renal artery 2. Gonadal artery 3. Common iliac artery 4. Internal iliac artery
What structure attaches onto the apex of the bladder?
Median umbilical ligament
What is the name of the muscular layer of the bladder?
Detrusor muscle
The bladder is supplied by branches of the internal iliac. What are the names of the two branches that supply the bladder in men?
- Superior vesical (from umbilical) and 2. Inferior vesical
In women what artery replaces the inferior vesical artery?
Vaginal artery
What is the parasympathetic nerve that innervates the bladder?
Pelvic splanchnic nerve (S2-4)
What is the function of the parasympathetic nerves on the bladder and internal urethral sphincter?
Overall effect: Micturition 🡪 relaxation of internal urethral sphincter + contraction of detrusor muscle
What is the sympathetic nerve that supplies the bladder?
Inferior hypogastric plexus (T10 🡪 L2 – thoracolumbar outflow)
What epithelium lines the bladder?
Transitional cell (same as for the ureter)
