What are the muscles of mastication? What nerve are they supplied by?
Temporalis Masseter Medial pterygoid Lateral ptergoid CNV3 - Mandibular division of trigeminal nerve
What are the attachments of the temporalis?
Coronoid process of mandible to temporal fossa
What are the attachments of the master?
Angle of the mandible to the zygomatic arch
What are the attachments of the lateral pterygoid?
Condyle of the mandible to ptyergotd plates of sphenoid bone
What are the attachments of the medial pterygoid?
Angle of the mandible (medial side) to pterygoid plates os of the sphenoid bone
Which is the only muscle of mastication responsible for opening the jaw (and not closing)
What is the CNS part of the course of the mandibular and maxillary division of the trigeminal nerve? (CN V2 and 3)
Attach to pons
What is the intracranial part of the course of the mandibular and maxillary division of the trigeminal nerve? (CN V2 and 3)
Inferior to the edge of the tentorium cerebella between the posterior and middle cranial fossae
What is the base of skull foramen part of the course of the mandibular division of the trigeminal nerve? (CN V3)
Through the foramen ovale in the sphenoid bone
What innervates the anterior (2/3) part of the tongue?
CN VII and CN V3
Which papillae are found on the anterior part of the tongue?
Foliate (taste buds)
Vallate (taste buds)
Fungiform (taste buds)
What innervates (brings taste and general sensation) the posterior part of the tongue?
CN IX (glossopharyngeal nerve)
What separates the anterior and posterior part of the tongue?
What is the CNS part of the course of the facial nerve? (CN VII)
Junction between pons and medulla
What is the intracranial part of the course of the facial nerve (CN VII)?
Directly into internal acoustic meatus in the posterior cranial fossa
What is the base of skull foramen part of the course of the facial nerve (CN VII)?
In through internal acoustic meatus
Out through stylomastoid foramen
What is the extracranial part of the course of the facial nerve? (CN VII)
Most fibres pass through stylomastoid foramen
The chords tympani (branch of CN VII) connects to the lingual nerve branch of?
CN VII parasympathetic axons supply (secretomotor) the?
Submandibular salivary gland and sublingual salivary gland
What provides general sensation to the superior half of the oral cavity (gingival oral vanity and palate)?
CN V2 (Maxillary division of trigeminal)
What provides general sensation so the inferior half of the oral cavity (gingiva of oral cavity and floor of the mouth)?
CN V3 (Mandibular division of the trigeminal)
The gag reflex is a protective reflex to prevent?
Foreign bodies entering the pharynx/larynx
The sensory part of the gag reflex is carried by nerve fibres within CN?
CN IX (Glossopharyngeal)
The motor part of the gag reflex is carried by nerve fibres within CN?
CN IX and CN X
Part of the reflex response to toughing the posterior wall of the _____ is to constrict the pharynx as the patient attempts to close it off as an entry point to the body
To numb the oral cavity for endoscopy, spraying local anaesthetic will “block” sensory action potentials in which cranial nerves?
Where does the CN V2 exit the base of the skull?
Foramen rotundam (Sphenoid bone)
What type of nerve supply does CN IX give?
Special sensory Sensory Motor Visceral afferent Parasympathetic
What is the CNS part of the course of the glossopharyngeal nerve (CN IX)?
What is the intracranial part of the course of the glossopharyngeal nerve (CN IX)?
Directly towards jugular foramen in the posterior cranial fossa
What is the base of the skull foramen part of the course of the glossopharyngeal nerve (CN IX)?
Junction between temporal bone and occipital bone - jugular foramen
What is the extracranial part of the course of the glossopharyngeal nerve (CN IX)?
Axons mainly pass to or from the tongue and palate
Posterior wall of oropharynx
Parasympathetic secretomotor to parotid salivary glands
The parotid gland crosses face secretes into mouth by which tooth?
Upper 2nd molar
The submandibular duct enters floor of mouth and secretes via?
The sublingual gland lays in floor of mouth and secretes via?
Several ducts superiorly
What are the three pairs of salivary glands?
What is the function of the extrinsic muscles of the tongue?
Change the position of the tongue during mastication, swallowing and speech
What is the function of the intrinsic muscle of the tongue?
Modify the shape of the tongue during function
What are the four extrinsic muscles of the tongue?
Palatoglossus (attach to palate)
Styloglossus (from styloid process)
Genioglossus (from mandible)
Hypoglossus (from hyoid bone)
All the tongue muscles except the palatoglossus are innervated by?
CN XII (Hypoglossal)
Palatoglossus is innervated by?
The vagus nerve
What is the CNS part of the course of the hypoglossal nerve (CN XII)?
Via many rootlets that attach to the medulla oblongata
What is the base of the skull foramen part of the course of the hypoglossa nerve (CN XII)?
Hypoglossal canal (occipital bone, anterior wall of foramen magnum)
What is the extracranial part of the course of the hypoglossa nerve (CN XII)?
Descend in neck lateral to carotid sheath
At level of hyoid bone it passes anteriorly towards the lateral aspect of the tongue
Supplies most of the muscles of the tongue
The superior, middle and inferior constrictor muscles of the pharynx all?
The extrinsic muscles of the pharynx are ______ but…?
Can’t control the sequence
The extrinsic muscles of the pharynx are innervated by?
All the extrinsic pharynx muscles insert onto the?
The inner layer of muscle of the pharynx is _______ muscle?
What supplies the longitudinal muscles of the pharynx?
Mainly CN X and IX
What does innervation by CN X and IX do to the pharynx?
Elevate pharynx and larynx
—Attach to larynx
Contract to shorten pharynx
Raise the larynx to close over the laryngeal inlet
Which muscle prevents drooling and what is it innervated by?
The tongue pushes the bolus of food posteriorly towards the oropharynx - this is action is innervated by?
Cranial nerve XII
Cranial nerve X allows sequential contraciton of the _________________ to push the bolus inferiorly towards the oesophagus
Pharyngeal constrictor muscles
At the same time as pharyngeal constrictor muscle contraction the ____________ of pharyngeal muscle contracts to raise the larnyx, shortening the pharynx and closing off the laryngeal inlet to help prevent?
What innervates the inner longitudinal layer of pharyngeal muscles
CN IX and X
The initiation of swallowing is voluntary/involuntary?
What is the enteric nervous system?
Extensive system of nerves found only in walls of the GI tract ; acts completely independently but can be influenced by signals from the ANS
Sympathetic influence of the ENS leads to?
Slowed down peristalsis
Parasympathetic influence to the ENS leads to?
Sped up peristalsis
The oesophagus is the inferior continuation of the?
Where dies the oesophagus begin?
Inferior edge of the cricopharynxgeus muscle (vertebral level C6)
How many sphincters are there in the oesophagus?
What runs on the surface of the oesophagus to supply the smooth muscles within the walls?
The oesophageal plexus
The para and sympathetic fibres of the oesophageal plexus act to alter the rate of?
When does the oesophageal plexus terminate?
Cardia of the stomach
What causes the sphincter effect of the lower oesophageal sphincter?
Contraction of the diaphragm and intrabdominal pressure being slightly higher than intragastric pressure + the oblique angle at which the oesophagus enters the stomach
A hiatus hernia can lead to ___-like symptoms because of the decreased effectiveness of the LOS
Where does the stomach mainly lie?
Left hypochondriac, epigastric and umbilical region (when the patient is supine)
What is the Z line of the stomach?
Abrupt change in wall mucosa
What makes up the foregut?
Oesophagus to mid-duodenum
Liver and gall bladder
What makes up the midgut?
Midduodenum to the proximal 2/3rds of transverse colon 1/2 pancreas
What makes up the hindgut?
Distal 1/3 of transverse colon to proximal 1/2 of anal canal
What is guarding?
Anterolateral abdominal wall muscles contract to ‘guard’ the abdominal organs when injury threatens or peritonitis
Describe the peritoneum?
Thin, transparent, semi-permeable serous membrane that lines the abdomino-pelvic cavity and organs
Peritoneum is a continuous membrane; parietal on the _______; visceral ______
Engulfs the organs
Where is the peritoneal cavity?
Beween the visceral and parietal peritoneum
Blood, pus or faeces in the peritoneal cavity will cause sever and painful inflammation called?
Intraperitoneal organs are almost completely covered in?
How mobile are intraperitoneal organs? List them
Liver, gallbladder, stomach, spleen, parts of SI
Organs with a mesentery are covered in?
Visceral peritoneum (wraps around the organ to form a double layer called the mesentery)
What defines retroperitoneal organs? List them
Only has visceral peritoneum on its anterior surface Located in retroperitoneum
Kidneys, adrenal gland, pancreas, ascending and descending colon
Mesentery usually connects?
Organs to the posterior body wall
What is omentum?
Double layer of peritoneum that connects stomach to adjacent organs
What is peritoneal ligaments?
Double layer of peritoneum that connect organs to one another on body wall
Mesentery has a core of?
Connective tissue with blood, lymph, nerve, lump nodes and fat
The mesentery proper is associated with?
The small intestine
What are the other types of mesentery besides the mesentery proper?
Transverse and sigmoid mesocolon
How many layers does the greater omentum have?
What is the macroscopic appearance of the greater momentum?
Hangs like an apron
What does the greater omentum attach to?
Attaches the greater curvature of the stomach to the transverse colon
How many layers does the lesser omentum have?
Where does the lesser momentum run?
Between the lesser curvature of the stomach and duodenum to the liver
What is the characteristic feature of the lesser momentum? What exists here?
Has a free edge
The omenta divide the peritoneal cavity into?
A greater and lesser sac
How do the greater and lesser sac communicate?
Via the mental foramen aka Foramen of Winslow
What makes up the portal triad?
Proper hepatic artery
Hepatic portal vein
Common bile duct
Inferiorly the peritoneum drapes over the superior aspect of the pelvic organs forming which pouches?
Males: retro-vesical pouch (aka Pouch of Douglas)
Females: vesico-uterine pouch/recto-uterine pouch
What is ascites?
Collection of fluid in the peritoneal cavity
What most commonly causes ascites?
Liver disease (cirrhosis causes portal hypertension)
Ascites can be drained by which procedures?
How can the pouch of Douglas be drained?
During abdo/para-cenesis a needle must be placed where? Why?
Lateral to the rectus sheath
Avoids the inferior epigastric artery (main supply to the abdominal wall)
Use USS guidance if available
Where do the inferior epigastric arteries arise from?
The external iliac medial to the deep inguinal ring
Between visceral and somatic pain; which is easy and which is hard to localise?
Somatic = easy to localise Visceral = hard to localise
What character is typical of visceral pain?
Dull, achy and nauseating
What character is typical of somatic pain?
Sharp and stabbing
What does colic pain indicate?
Organs within the abdominal cavity including visceral peritoneum are innervated by?
Visceral (sensory) afferents
ANS (can influence ENS)
The abdominal wall from skin to parietal peritoneum is innervated by (3)?
Sympathetic nerve fibres (no real parasympathetic supply)
Sympathetic nerves to the abdominal organs leave the spinal cord between?
T5 and L2
Sympathetic nerves to the abdominal organs leave the spinal cord between T5 and L2 and enter the _____.
How do they leave the sympathetic chains?
Sympathetic chains (bilaterally) They don't synapse - leave sympathetic chains within abdomino-pelvic splanchnic nerves and synapse at the pre vertebral ganglia which are located anterior to the aorta at the exit points of the major branches of the abdominal aorta.
Postsynaptic sympathetic nerves fibres pass from the pre vertebral ganglia (coeliac/SMA/etc.) onto the surface of?
The arterial branches of the abdominal aorta
The postsynaptic sympathetic nerve fibres from the pre vertebral ganglia (coeliac/SMA/etc.) take part in the ________ with other never fibres on arterial branches of the abdominal aorta
How do postsynaptic sympathetic nerve fibres pass from the pre vertebral ganglia to the smooth muscle and glands of the organ?
By hitching a ride to/away with the other nerve fibres in the periarterial plexuses on the surface of the arterial branches of the abdominal aorta
How are sympathetic nerves for the adrenal gland unique?
Leave spinal cord at T10-L1 and enter the abdominosplanchnic nerves.
Don’t synapse at the pre vertebral ganglia
Carried with periarterial plexus to the adrenal gland Synapse directly onto the cells
The vagus nerve pre-synaptic nerve fibres enter the abdominal cavity on the surface of the?
The vagus nerve travels into ___________ around the abdominal aorta
The vagus nerve supplies parasympathetic nerve fibres to what in the abdomen?
Abdominal organs up to the distal end of the transverse colon
Pelvic splanchnic nerves (S2,3,4) presynaptic parasympathetic nerve fibres innervate?
Smooth muscle/glands of the descending colon to the anal canal (Supply genitalia and descending colon)
(RHYME): S2, 3, 4 keep..
…your guts off the floor
Where does foregut pain tend to be felt?
In the epigastric region
Where does midgut pain tend to be felt?
Where is hindgut pain usually felt?
Foregut structures enter the spinal cord at approx.?
Midgut structures enter the spinal cord at approx.?
Hindgut structures enter the spinal cord at approx.?
Somatic motor sensory and sympathetic nerves supplying the abdominal body wall are conveyed within?
Thoracoabdominal nerves 7-11th intercostal nerves
The 7th to 11th intercostal nerves travel anteriorly, then leave the intercostal spaces in the plane between?
The internal oblique and transversus abdominus as thoraco-abdominal nerves
Where do subcostal nerves leave the spinal cord?
T12 anterior ramus
Where do Iliohypogastric nerves leave the spinal cord?
Half of the L1 anterior ramus (suprapubic)
Where to Ilioinguinal nerves leave the spinal cord?
Half of the L1 anterior ramus(pubic)
How does pain from an appendicitis usually present?
Usually initially dull, aching pain in the umbilical region As an appendicitis worsens, the appendix will start to irritate the right iliac fossa
Why is pain from an appendicitis usually initially dull, aching pain in the umbilical region
Because visceral afferents from midgut organs enter the spinal cord between T8-T12 (appendix is T10 = umbilicus)
List the parts of the SI and LI?
Duodenum, jejunum, ileum
Caecum, appendix, ascending, transverse, descending, sigmoid
The liver, spell, gallbladder, pancreas and small intestine all produce?
Bilirubin and bile
What is bilirubin?
Normal by-product of the breakdown of red blood cells
What is jaundice (icterus)?
Yellowing of the sclera and skin caused by an increase in blood levels of bilirubin
Where does RBC breakdown mainly occur?
In the spleen
Bilirubin is used to form ___ in the liver
Bile is important for?
The normal absorption of fats from the SI
Contributes to pancreatic enzymes in digesting food in the SI
What is the function of the liver?
Other metabolic functions
What is the surface anatomy of the liver?
Mainly located in the RUQ
Protected by ribs 7-11
What happens to the position of the liver during inspiration?
The liver is inferior to?
The right hemiödiaphragm
How is the gallbladder anatomically related to the liver?
It is posterior and inferior to the liver
The hepatic flexure is _____ to the liver
The right kidney, adrenal gland, IVC and abdominal aorta are _____ to the liver
The stomach is ______ at the ______ side of the liver
What are the 4 anatomical lobes of the liver?
Caudate lobe (superior)
Quadrate lobe (inferior)
Which of the lung lobes contains a bare area?
What is meant by a “bare area”?
Not touched by any peritoneum = pure liver parenchyma
What is the falciform ligament?
A remnant of ventral mesentary
What is the round ligament?
A remnant of the umbilical vein
The porta hepatis is closely associated with the gallbladder at _______ aspect
How many functional divisions of the liver are there?
Why can individual functional lobes be removed from the liver?
Because each lobe has a branch of the hepatic artery, hepatic portal vein and bile drainage (to bile duct) and venous drainage (to IVC)
The hepatic veins directing deoxygenated blood from the liver come tiger as _ veins before entering the IVC
What does the portal triad contain?
Hepatic portal vein
Hepatic artery proper
The portal triad runs within which ligament?
The hepato-duodenal ligament
The coeliac trunk is the ___ midline branch of the aorta
Is the coeliac trunk intra or retroperitoneal?
Where does the coeliac trunk leave the abdominal aorta?
The coeliac trunk trifurcates into?
Left gastric artery
Common hepatic artery
The common hepatic artery branches into? then becomes?
Hepatic artery proper
The splenic artery has a _______ course along the _____ border of the pancreas
Is the spleen intra- or retroperitoneal?
Where is the spleen?
What are the anatomical relations of the spleen?
Splenic flexure inferiorly
Left kidney medially
Major blood supply to the stomach comes from?
The right and left gastric arteries and right and left gastro-omental arteries
Where do the right and left gastric arteries anastomose?
Along the junction of the lesser curvature and lesser omentum of the stomach
Where do the right and left gastro-omental arteries anastomose?
Along the junction of the greater omentum and greater curvature of the stomach
Blood supply to the liver comes from?
Right and left hepatic arteries
The right and left hepatic arteries are branches of?
The hepatic artery proper
Histologically, the liver consists of?
Hexagonal iver lobules with a central vein at the centre and an interlobular portal triad at each corner
What does the interlobular portal triad consist of?
Branch of the HPV, branch of HA and biliary duct
> Both the hepatorenal recess (Morrison’s pouch) and the sub-phrenic recess are located within the?
The hepatorenal recess is one of the lowest parts of the peritoneal cavity when the patient is?
Pus in the sub-phrenic recess can drain into the _____ when the patient is bedridden
The HPV drain blood from where into the liver for 1st pass metabolism
Fore, mid and hindgut
The HPV is formed by?
The splenic and superior mesenteric vein
The IVC is retroperitoneal and drained cleaned blood from the ________ into the right atrium
Anatomically how are the portal triad structures arranged anterior to posterior?
What is the function of the gallbladder?
Store and concentrate bile between meals
The gallbladder lies on the ______ aspect of the liver (often firmly attached) and ____ to the duodenum
Bile flows in and out of the gall bladder via?
The cystic duct
Blood supply to the gall bladder comes from the?
In 75% of people the cystic artery is a branch of the?
Right hepatic artery
The right cystic artery is located in the?
Cystohepatic triangle (of Calot)
What makes up the triangle of Calot (aka cystohepatic triangle)
Common hepatic duct
Inflammation of the gallbladder/cystic duct can follow irritation from or impaction of a?
The gall bladder is part of the ____-gut?
Visceral afferents from the gall bladder enter the spinal cord at?
Early pain from cholyangitis will develop in the ______
Where can pain from cholyangitis arise besides the epigastrium?
Hypochondrium +/- pain referral to the right shoulder as a result of anterior diaphragmatic irritation
What is a cholecystectomy?
Surgical removal of the gallbladder
What are the parts of the pancreas?
The head of the pancreas is surrounded by?
C-shaped curve of the duodenum
What are the 4 parts of the duodenum?
For each of these parts state whether they are intra- or retroperitoneal.
Superior (intra) with duodenal cap
What is the start and end of the duodenum?
The duodenum secretes _____ and ______ into the blood
Pain from duodenal ulcers to to present in which region?
What is found posterior to the pancreas?
Right kidney and adrenal gland IVC Bile duct Abdominal aorta Superior mesenteric vessels (start at head of pancreas) Left kidney and adrenal gland Part of portal venous system
What is found anterior to the pancreas?
What is found superoposteriorly to the pancreas?
What are the exocrine functions of the pancreas?
Acinar cells release digestive enzymes into the pancreatic duct
What are the endocrine functions of the pancreas?
Islets of Langerhans secrete insulin and glucagon into the blood stream
The bile duct travels _____ to the superior part of the duodenum to a grove in the posterior aspect of the ____ where it joins with pancreatic duct to form the?
Ampulla of Vader/Hepatopancreatic ampulla
The ampulla of Vater/hepatopancreatic ampulla drains into the duodenum via?
The major duodenal papila
It is possible to have accessory pathways of the pancreatic duct into the duodenum via?
Minor duodenal papillae
Where are the 3 points of flow control of bile?
Bile duct sphincter
Pancreatic duct sphincter
Sphincter of Oddi
What does ERCP stand for?
Endoscopic retrograde cholangiopancreatography
What is ERCP used for?
To study the pancreas and biliary tree
Jaundice is caused by?
Increased levels of bilirubin in the blood
What are extra-hepatic causes of jaundice?
Obstruction of the biliary tree (gallstones/carcinoma) leading to back-up of bile to the liver and overspill in the blood
Blockage of the ampulla can causes bile to be diverted into the pancreas leading to?
Where is pancreatitis pain felt?
Epigastric and umbilical region
+ Patient’s back
Acute pancreatitis can be caused by?
Gall stone obstruction leading to reflux of bile and pancreatic juice into the main pancreatic duct
What is Grey-Turner’s and Cullen’s sign of acute pancreatitis? What is the cause?
Vascular haemorrhage can cause blood accumulation in the retroperitoneal space
Grey-Turner’s sign = right +/- left flank
Cullen’s sign = around umbilicaus via falciform ligament
Where does the jejunum begin?
At the duodenaljejunal flexure
Where does the ileum end?
At the ileocaecal junction
Which, of the jejunum and ileum, is thicker and heavier?
Which, of the jejunum and ileum, has more fat?
Which, of the jejunum and ileum, is more vascular?
Which, of the jejunum and ileum, has sparse folds?
Which, of the jejunum and ileum, contains Peyer’s Patches?
What is the arterial supply to the jejunum/ileum?
SMA via ileal and jejunal arteries
Where does the SMA leave the aorta?
What drains the jejunum/ileum?
The jejunum/ileal veins drain into the?
The SMV drains into the?
The vascular supply to the jejunum and ileum travels within the?
The SMA and SMV are located ____ to the neck of the pancreas
The SMA and SMV travel ________ to the uncinate process to enter the mesentery proper
Fat digestion is aided by _______. With chylomicrons they are absorbed into specialised lymphatic vessels in the SI called?
Lacteals travel through lymphatics and enter the venous system at?
Left venous angle
Lymph vessels tend to travel alongside?
Minor blood supply to the stomach comes from?
Posterior gastric arteries
Short gastric arteries
What ducts form to make the bile duct?
Common hepatic duct
Where does the bile duct drain?
Into the 2nd part of the duodenum
What are the main groups of lymph vessels draining the abdomen and where soecifically do they drain?
Lumbar (kidneys, posterior abdominal wall, pelvis, lower limbs)
How many paracolic gutters are there between the lateral edge of the ascending/descending colon and the abdominal wall?
The paracolic gutters are part of the _______ and are potential sites for ____
Pus or fluid collection
What are omental appendices of the colon?
Small pouches of the peritoneum filled with fat and situated along the colon, but are absent in the rectum
What are the teniae coli of the colon?
3 distinct longitudinal bands of thickened smooth muscle, running from the caecum to the distal end of the sigmoid colon
The 3 bands of the teniae coli of the colon come together at the caecum to form?
What are haustra?
Small pouches formed by sacculation; because the tenure coli are shorter than the intestine, the colon becomes sacculated between them forming hasutra
The caecum and appendix both lie in the?
Right iliac fossae
The appendiceal orifice is located?
On the posteromedial wall of the wall of the caecum
The appendiceal orifice corresponds to _______ on the anterior abdominal wall approximately ___ of the way between the _____ to _______-
ASIS (anterior superior iliac spine)
McBurney’s point is the theoretical area of?
Maximal tenderness of appendicitis
The appendix is typically located?
Behind the caecum (position is variable)
Where does the sigmoid colon lie?
In the LIF
The long sigmoid mesocolon gives the sigmoid colon a?
Considerate degree of mobility
What is the risk associated with the considerate degree of mobility of the sigmoid colon?
Risk of twisting during embryological development (sigmoid volvulus) resulting in bowel obstruction and infarction if untreated
The abdominal aorta is a midline retroperitoneal structure anterior to vertebral bodies and left to the?
What are the midline branches of the abdominal aorta and at which vertebral level do they come off?
Coeliac trunk - T12
SMA - L1
IMA - L3
What are the lateral branches of the abdominal aorta and at which vertebral level do they come off?
Left/right renal artery - L1
Gonadal arteries - L2
Lumbar arteries - L4
What do the lumbar arteries supply?
The posterolateral body wall
The bifurcation of the abdominal aorta into the iliac arteries occurs at which vertebral level?
The common iliac arteries divide into?
External and internal iliac arteries
What are the branches of the SMA (in order)
Inferior pancreaticoduodenal (pancreas/duodenum) Middle colic artery (transverse colon) Right colic artery (ascending colon) Ileocolic branches (ascending colon) Appendicular (runs within mesoappendix)
What do the ileocolic branches of the SMA give off?
Jejunal and ileal arteries
What is a noticeable difference between the jejunal and ideal arteries’ vasa rectae and arcades?
The jejunal arteries have longer vasa rectae and larger & fewer arcades than the ileal arteries
What is the marginal artery of Drummond (aka juxta-colic artery)?
Arterial anastamoses between the SMA and IMA
Whatis function of the marginal artery of Drummond?
Help prevent ischaemia of the intestines by providing collateral routes for blood flow
The rectum and anal canal are perfused by?
The superior rectal artery (branch of IMA)
The inferior rectal artery supplies?
The perineum, genitalia and rectum
What is the pectinate line?
Division of upper 2/3rds of the anal canal and lower 1/3rd
The pectinate line is the site of border between which arteries?
Superior, middle and inferior rectal arteries
At the pectinate line there are anastamoses between which vessels?
Superior, middle and inferior rectal arteries
What are the two venous systems?
Portal and systemic venous system
The hepatic portal vein drains blood from ______- to the liver for first pass metabolism
Fore, mid and hindgut
The splenic vein drains from ______ to _______
Foregut structures to hepatic portal vein
The SMV drains blood from ______ to ______
Midgut structures hepatic portal vein
The IMV drains blood from ______ to _______
Hindgut structures to splenic vein
Porto-systemic anastomoses consist of?Varices/enlargement of these vessels is the result of?
Small collateral valve-less veins
What are the anastomoses at the distal end of the oesophagus?
Inferior part drains into the HPV
Superior part drains into azygous vein
What are the anastomoses at the skin around the umbilicus?
Connection between para-umbilical veins (to HPV along round ligament of liver) and epigastric veins (to caval system)
What are the anastomoses at the rectum/anal canal?
Rectum and superior anal canal (superior rectal vein) drain into IMV
Inferior part of GI tract (middle and inferior rectal veins) drains into internal iliac veins
What can cause portal hypertension?
Liver pathology (cirrhosis) +/- tumour compressing the HPV leading to reversal of blood flow (varicosed collateral veins)
What is the clinical presentation of portal hypertension?
Caput medusa dilated paraumbilical and epigastric veins)
Prolapse of rectal varicose can lead to?
What is haematemesis? What are the two main causes?
Peptic ulcer in stomach/ duodenal wall erodes
Bleeding from oesophageal varices
What are the branches of the inferior mesenteric artery in order?
Left colic artery (descending colon)
(Branch of sigmoid: superior rectal artery)
Where are the three sites of porto-systemic anastomosis in the GI tract?
At the distal end of the oesophagus
Skin around the umbilicus
Rectum/anal canal (and descending colon)
Visceral afferents from the rectum send _____ signals to the brain
What can affect faecal contience?
Neural (dementia, stroke, MS, trauma) pathology
Age-related natural nerve degeneration
Consistency of stool
Where is the pelvic cavity?
Between the pelvic inlet and pelvic floor (within bony pelvis)
What separates the pelvic cavity and perineum?
The pelvic diaphragm
The pelvic cavity is ______ with the abdominal cavity
What makes up the pelvic floor?
The levator ani muscle
The levator ani muscle forms the musculo-fascial inferior part of?
The pelvic cavity
Openings in the pelvic floor allow which structures to pass through into the perineum?
The sigmoid colon becomes the rectum at the _______ junction at vertebral level?
Rectum becomes anal canal anterior to the ____ just before passing through _______ muscle
Tip of the coccyx
The walls of the rectal ampulla can relax to?
Accomodate faecal material
What is the difference in macroscopic appearance of the rectum between when its empty and full?
Goes from S-shape to straight
The superior rectum is covered by?
The rectouterine/-vesicle pouch lies ____ to the superior rectum
The prostate gland/vagina lies ___ to the ________ rectum
What makes up the levator ani muscle?
Puborectalis (swing around rectum and attaches to pubis on either side)
Pubococcygeus (pubic bone - coccyx)
Ileococcygeus (ilea region - coccyx)
What innervates the levator ani?
The “nerve to levator ani”
The nerve to lavator ani is a branch of which two nerves?
Where does the puodendal nerve originate from?
Pubcorectalis contraction decreases the _______ angle
The puborectalis is ____ muscle
What are the two sphincters in the anal canal?
Internal and external anal sphincter
Outline the internal anal sphincter - type of muscle, location, nerve supply and function
Superior 2/3 of anal canal
Contraction stimulated by sympathetic nerves and inhibited by parasympathetic
Usually closed, releases reflexively to distension of rectal ampulla
Outline the external anal sphincter - type of muscle, location, nerve supply and function
Inferior 1/3 of anal canal
Contraction stimulated by puodendal nerve
Sympathetic nerve supply to the rectum/anal canal comes from ______ -> inferior mesenteric ganglia which synapses via ________ around branches of the ____
T12-L2 periarterial plexus
Sympathetic innervation of the rectum/anal canal stimulates?
Contraction of internal anal sphincter and inhibition of peristalsis
Parasympathetic fibres from ______ via pelvic _______ nerve synapse in __________
S2,3,4 (spinal cord level)
Walls of rectum
What is the effect of parasympathetic innervation of the rectum/anal canal?
Inhibit internal anal sphincter and stimulate peristalsis
Visceral afferents follow _______ back to ______. They sense stretch, _____, etc.
S2,3,4 (spinal cord level)
Somatic motor supply from the puodendal nerve comes from _______
S2,3,4 (spinal cord level)
Nerve to levator ani comes from?
S2,3,4 (spinal cord level)
Nerve to leaver ani stimulates?
Contraction of external anal sphincter and puborectalis
The puodendal nerve exits the pelvis via?
Greater sciatic foramen
Pudodenal nerve enters the perineum via?
Lesser sciatic foramen
Stretching of the puodenal nerve and/or tearing of the fibres of the puborectalis or external anal sphincter muscle can result in weakened muscle leading to?
Give an example of when this can occur?
During vaginal delivery
The pectinate line is the junction between _____ and _______ during embryological development
Endoderm (GI tract)
What is the nerve supply superior to the pectinate line?
What is the arterial supply superior to the pectinate line?
What is the venous drainage superior to the pectinate line?
What is the lymphatic drainage superior to the pectinate line?
What is the nerve supply inferior to the pectinate line?
What is the arterial supply inferior to the pectinate line?
Internal iliac artery
What is the venous drainage inferior to the pectinate line?
To internal iliac vein (systemic)
What is the lymphatic drainage inferior to the pectinate line?
Superficial inguinal nodes
Pelvic lymphatics tend to follow the ____
What are the main lymph node groups in the pelvis?
The internal iliac nodes drain…
Inferior pelvic structures
The external iliac nodes drain …
The common iliac nodes drain…
External and internal iliac nodes
The lumbar nodes drain…
Common iliac nodes
The IMA supplies the hindgut which extends unto the pectinate line. The remainder is supplied by?
The internal iliac artery
What drains the hindgut? The remainder?
Internal iliac vein
What are haemorrhoids? Why are they different than rectal varices?
Prolapse of rectal venous plexuses
Not related to portal hypertension - increased pressure (e.g. chronic constipation, straining, pregnancy)
Ischioanal fossa (R&L) lie on either side of the?
The ischioanal fossa communicate with each other ______
Pus collection within the ischioanal fossae can lead to…
A PR exam is assessing the stregth of which sphincter?
External anal sphincter