Anatomy Flashcards
The gall bladder area can be palpated around _________.
the tip of the right 9th costal cartilage
What are the bounds of the abdomen?
Superiorly: cartilages of 7-10th ribs
Inferiorly: inguinal ligament and pelvis
How are the 4 quadrants of the abdomen divided?
By median and transumbilical plane
How is the abdomen divided into 9 regions?
1) Subcostal (inferior borders of 10th costal cartilage/body of L3 vertebra)
2) Intertubular (btwn iliac tubercles and L5 vertebra
3) 2 midclavicular planes
What are the 9 regions of the abdomen?
1) Epigastric
2) Umbilical
3) Pubic/hypogastric
4/5) R/L hypochondrium
6/7) R/L flank
8/9) R/L Groin
What are the organs found in the right upper quadrant of the abdomen?
1) Liver
2) Gall bladder
3) Pylorus of stomach
What are the organs found in the left upper quadrant of the abdomen?
1) Stomach
2) Spleen
What are the organs found in the right lower quadrant of the abdomen?
1) Coecum
2) Appendix
What are the organs found in the left lower quadrant of the abdomen?
1) Descending colon
2) Sigmoid colon
Where is the transpyloric plane?
Lower border of L1
(cuts through pylorus of stomach, tips of 9th costal cartilages)
The linea alba passes in the _____ line to the symphysis pubis and is formed by the fusion of the ______ on both sides.
median line
formed by fusion of rectus sheath of both sides
The superficial facia of the abdominal wall are part of the ______ layer and are composed of:
Subcutaneous tissue:
1) Superficial fatty layer (Camper fascia)
- continuous with superficial fat of rest of body
2) Deep membranous layer (Scarpa fascia)
- blends with deep fascia of upper thigh, penis, scrotum and into perineum as Colle’s fascia
What are the layers of the abdominal wall from superficial to deep (6)?
1) Skin
2) Subcutaneous tissue (superficial fatty, deep membranous)
3) Muscles and aponeurosis
4) Deep fascia
5) Extraperitoneal fat
6) Parietal peritoneum
The abdominal and pelvic cavities are (continuous/separated).
Continuous but arbitrarily separated by pelvic inlet
What separates the the thoracic and abdominal cavities?
Diaphragm
True or false: the upper part of the abdominal extends beneath the thoracic cage.
True
What are the muscles of the anterior abdominal wall?
Paired vertical rectus abdominis muscles within rectus sheath.
What are the muscles of the lateral abdominal wall?
1) External oblique
2) Internal oblique
3) Transversus abdominis
The muscle fibres of the lateral abdominal wall continue anteriorly as _________.
Aponeurotic sheets that contribute to the rectus sheath of the anterior abdominal wall
The muscle fibres of the external oblique muscles extend in what direction?
Inferomedially
Which of the 3 lateral abdominal wall muscles have a free posterior border?
External oblique
How is the inguinal ligament formed?
The lower aponeurotic edge of the external oblique muscle rolls inwards and stretches between the anterior superior iliac spine to the pubic tubercle
What significant structure is found immediately above and lateral to the pubic tubercle?
The superficial inguinal ring (hole in external oblique aponeurosis)
The muscle fibres of the internal oblique muscles extend in what direction?
Inferoposteriorly
The lowest fibres of the internal oblique and transversus abdominal join to form the _______.
Conjoint tendon
The muscle fibres of the tranversus abdominis muscles extend in what direction?
Horizontally
(except most inferior)
Where does the neurovascular plane lie in the lateral abdominal wall?
Between the internal oblique and transversus abdominus
What nerves supply the rectus abdominus?
Segmental nerve (T7-12)
The rectus abominis is divided into segments by ____________ which are attached to the _____________.
Divided by tendinous intersections which are attached to the anterior wall of the rectus sheath
Haematomas of the rectus abdominis is (localised/diffuse)
localised
In a paramedian incision, which muscle is displaced laterally?
The rectus abdominis
What encloses the rectus abdominis?
Rectus sheath
The rectus abdominis has ____ heads.
2
What are the superior and inferior attachments of the rectus abdominis?
Superior:
1) 5-7 costal cartilages
2) Xiphoid process
Inferior:
1) Symphysis pubis
2) Pubic crest
What structures form the rectus sheath?
The aponeuroses of the lateral abdominal wall muscles (EO,IO,TA)
Where do the rectus sheaths meet?
At the midline (Linea alba)
How does the arrangement of the rectus sheath differ above and below the umbilicus?
Above umbilius:
1) External: anterior
2) Internal: encloses rectus abdominis
3) Transversus: posterior
Below umbilicus:
- all anterior to rectus muscle
Above the arcuate line, the rectus sheath ____________.
Below the arcuate line, the rectus abdominis is in contact with the ____________.
Above: posterior wall of rectus sheath stops
Below: RA is in contact with transversalis fascia
What is the transversalis fascia?
Fascia lining anterolateral abdominal wall between transversus abdominis muscle and peritoneum.
What and where is the hole in the transversalis fascia?
Deep inguinal ring: ~1.5cm above midpoint of inguinal ligament
Describe the blood supply of the rectus muscle.
1) Superior epigastric artery (terminal branch of internal thoracic/mammary)
2) Inferior epigastric (branch of external iliac)
Which 2 vessels of the abdominal wall anastomose to form a bypass to the abdominal aorta?
1) Superior epigastric artery (terminal branch of internal thoracic/mammary)
2) Inferior epigastric (branch of external iliac)
(can compensate for each other)
Describe the blood supply of the flank muscles.
1) Intercostal arteries 7-11
2) Subcostal artery
3) Lumbar arteries
4) Deep circumflex iliac arteries
Describe the venous drainage of the rectus muscles.
1) Superior epigastric vein
2) Inferior epigastric vein
Describe the venous drainage of the flank muscles.
1) Intercostal veins 7-11
2) Subcostal vein
3) Lumbar veins
4) Deep circumflex iliac veins
What are the nerves supplying the external oblique muscle?
Anterior rami of T7-11
What are the nerves supplying the internal oblique muscle?
Anterior rami of T7-12 and L1
What are the nerves supplying the rectus abdominis muscle?
Anterior rami of T7-12 spinal nerves
What are the dermatomes supplying the epigastrium?
T7-9
What is the dermatome supplying the umbilicus?
T10
What are the dermatomes supplying the region inferior to the umbilicus?
T11-12
What are the dermatomes supplying the inguinal and pubis?
L1
The parietal peritoneum has/does not have somatic sensory supply while the visceral peritoneum has/does not have somatic sensory supply.
Parietal: somatic sensory from segmental nerves of body wall
Visceral: no somatic sensory
What are 4 functions of the anterolateral abdominal wall?
1) Compress the abdomen and increase intra-abdominal pressure to aid expiration, urination, defecation, parturition, heavy lifting
2) Helps to maintain posture
3) Supports viscera
4) Flex and rotate trunk
The rectus abdominis is the most powerful flexor of the vertebral columns by partnering with which muscles?
external and internal oblique
What is the inguinal canal?
A oblique passageway extending from the deep inguinal ring (hole in transversalis fascia) to superficial inguinal ring (hole in external oblique aponeurosis) above the medial half of the inguinal ligament.
What are the structures within the inguinal canal in males?
1) Spermatic cord
2) Ilioinguinal nerve
3) blood vessels
4) lymphatic vessels
What are the structures within the inguinal canal in females?
1) round ligament
2) ilioinguinal nerve
3) blood vessels
4) lymphatic vessels
What forms the walls of the inguinal canal?
Anterior:
1) EO aponeurosis
2) IO (lateral 3rd only)
Posterior:
1) Transversalis fascia
2) Medially conjoint tendon
Floor:
1) Rolled inferior edge of EO aponeurosis (inguinal ligament)
Roof:
1) Arching fibres of IO
2) Medially conjoint tendon (w transverse abdominis)
What is a hernia?
An abnormal protrusion of an organ usually contained by a structure
What are the components of a hernia?
1) Sac (eg. peritoneum)
2) Defect (hole)
3) Contents (eg. bowel)
What is a reducible vs irreversible hernia?
Reducible: sac can return to containing cavity
What is an obstructed hernia?
Sac contained blocked bowel
What is a strangulated hernia?
Sac has compromised blood supply
What are 3 factors that prevent hernias in the inguinal canal?
1) Oblique passage
2) Posterior wall reinforced by conjoint tendon
3) Increased intra-abdominal pressure (roof compresses contents on floor so cannot be herniated)
What is the difference between a direct and indirect inguinal hernia?
Direct:
- through defect in posterior wall of inguinal canal
- medial to inferior epigastric vessels
- older age group (chronic straining, weak musclulature)
Indirect:
- through dilated deep ring into scrotum
- indirect path through abdominal wall
- most common (younger adults, childrens)
In a px with an inguinal hernia, the (superficial/deep) inguinal ring is palpable abovce and lateral to the pubic tubercle by invaginating the scrotal skin with a finger.
Superficial
(if ring is dilated, may admit finger w/o pain and will produce impulse when cough)
How do you differentiate a femoral and inguinal hernia?
Femoral hernia appear below and lateral pubic tubercle
Inguinal hernia appear above and medial to pubic tubercle
- femoral also irreducible, hot and painful due to strangulation
The peritoneum is a ____ membrane lining the _______ and investing the ______.
Serous single membrane of simple squamous epithelium (mesothelium)
- lines abdominopelvic cavity
- invests viscera
The parietal peritoneum lines the ______ while the visceral peritoneum covers _____.
Parietal: line cavity
Visceral: cover organs
The parietal peritoneum is supplied by the same blood/lymphatic supply as _____________ and thus is supplied by (somatic/visceral) sensory neurons.
Parietal: same as region of abdominal wall it lines
Somatic sensory
The visceral peritoneum is supplied by the same blood/lymphatic supply as _____________ and thus is supplied by (somatic/visceral) sensory neurons.
Visceral: same as organ it covers
Visceral sensory
Where is visceral pain experienced in the epigastric region normally referred from?
Foregut derivates (eg. Stomach, Liver, Pancreas, Gallbladder)
Where is visceral pain experienced in the umbilical region normally referred from?
Midgut derivates (eg. small and large intestines)
Where is visceral pain experienced in the hypogastric/pubic region normally referred from?
Hindgut derivates (eg. Colon)
What is the difference between the peritoneum in males vs females?
Males: completely closed
Females: communications w vagina, uterine tubes/cavity
(pathway for infection)
What is an omentum?
Double layered extension/fold of peritoneum
The lesser omentum extends from ______ to ______ whereas the greater omentum extends from ______ to ______.
Lesser: liver to lesser curvature of stomach
Greater: greater curvature of stomach to transverse colon
What is a peritoneal ligament?
A peritoneal fold connecting organ to another or body wall
(2 ligaments can form omentum eg. hepatogastric + hepatoduodenal ligament → lesser omentum)
What is a mesentery?
Peritoneal fold connecting organ to posterior abdominal wall
- conduit for vessels, nerves and lymphatics supplying viscera
The portal vein, hepatic artey and bile duct run within the (greater/lesser) omentum near its free edge.
Lesser
What are 10 retroperitoneal structures?
SANDPUCKER
Suprarenal glands
Aorta and IVC
Nerves (lumbar plexus, sympathetic trunk)
Duodenum (X 1st part)
Pancreas (X tail part)
Ureter
Colon (X cecum, transverse, sigmoid)
Kidneys
Esophagus
Rectum
What are 9 intraperitoneal organs?
SLUGS DACE
S - Stomach
L - Liver
U - Abdominal Esophagus
G - Gallbladder
S - Spleen
D - Distal Duodenum, Jejunum, Ileum
A - Appendix
C - Cecum
E - Sigmoid Colon
What is the epiploic/omental foramen/foramen of Winslow?
Passage btwn passage sac and lesser sac, allowing communication between both sacs
What are the 4 boundaries of the epiploic foramen?
Anterior: bile duct, hepatic artery, portal vein
Posterior: IVC and diaphragm
Superior: Caudate lobe of Liver
Inferior: 1st part of duodenum
At which spinal segment level does the esophagus pierce the diaphragm?
T10
The stomach lies between the _______ (Superior) and __________ (inferior) and lies in the ___________ regions of the abdomen.
Between esophagus (superior) and umbilical (inferior).
In (i) epigastric, (ii) umbilical, (iii) left hypochondriac regions
What are the 4 main regions of the stomach?
1) Cardia
2) Fundus
3) Body
4) Pylorus
What are the 2 orifices of the stomach?
1) Cardiac (gastroesophageal junction)
2) Pyloric orifice
What 5 structures does the stomach rest on?
1) Spleen
2) L kidney and adrenal gland
3) Splenic artery
4) Pancreas
5) Transverse mesocolon
What are the anterior relations of the stomach (2)?
1) Left lobe of the liver
2) Diaphragm
What are the superior relations of the stomach?
Left dome of diaphragm
What are the posterior relations of the stomach?
1) Lesser sac (omental bursa)
2) Pancreas
The interior of the stomach is lined by _______ which is thrown into _______ when contracted.
Gastric mucosa throws into mucosal rugae when contracted
What is a barium meal?
Radiograph using barium showing stomach and duodenum
What are the embryonic divisions of the GIT in an adult?
Foregut: distal 3rd of esophagus - 2nd part of duodenum (bile duct entrance)
Midgut: 2nd part of duodenum - 2/3 of transverse colon
Hindgut: Distal 1/3 of transverse colon to rectum
What are the 9 branches of the abdominal aorta?
Anterior midline: unpaired visceral (alimentary tract)
1) Celiac T12
2) Superior mesenteric L1
3) Inferior mesenteric L3
Lateral: paired visceral (urogenital and endocrine)
1) Suprarenal L1
2) Renal L1
3) Gonadal L2
Postero-lateral: paired parietal (diaphragm, body wall)
1) Subcostal L2
2) Inferior phrenic T12
3) Lumbar L1-4
What are the 3 branches of the celiac trunk (T12)?
1) Common hepatic
2) Left gastric
3) Splenic
Describe the arterial supply of the stomach.
Gastric arteries:
1) L/R gastric arteries
2) L/R gastro-omental arteries
3) Short gastric arteries
Describe the venous drainage of the stomach.
Gastric veins (parallel to gastric arteries) → L/R Gastric veins (tributaries of portal vein)
Describe the lymphatic drainage of the stomach.
Gastric lymphatic vessels along greater and lesser curvature (gastric, R/L gastro-omental nodes) → celiac nodes → thoracic duct
Describe the nerve supply of the stomach.
1) Sympathetic nerves fibres T5-9
2) Parasympathetic nerve fibres from R and L vagus nerves
The T5-9 sympathetic nerves stimulate ________.
Pyloric sphincter
The parasympathetic nerve fibres of the vagus nerves stimulate ________________.
1) Peristalsis of stomach
2) Secretion of gastric glands (secretomotor)
What is the ganglion for the sympathetic nerves supplying the stomach?
Celiac ganglion (from greater splanchic nerves)
Describe how visceral pain from a gastric ulcer would be referred?
Visceral pain fibres supplying stomach transmit to neurons from T5-T9 spinal sensory ganglia (supply dermatomes supplying the epigastric region)
The Liver and the inferior surface of the Diaphragm and separated by _______.
Subphrenic recess
What is the hepatorenal recess?
Peritoneal cavity on right side of body between liver and right kidney + adrenal gland
The liver has 2 surfaces:
The diaphragmatic surface is covered with peritoneum except ________.
The visceral surface is covered with peritoneum except ____________.
Diaphragmatic: except bare area
Visceral: except bed of gall bladder and porta hepatis
The liver is attached to the:
i)________________
ii)________________
iii)________________
i) Anterior abdo wall by falciform ligament (divides lobes)
ii) Stomach by hepatogastric ligament
iii) Diaphragm by coronary ligaments
The right anatomical but left functional lobe includes the ________ and _____ lobe
Right anatomical, Left functional lobe
- Caudate (superior)
- Quadrate (inferior)
What are the relations of the visceral surface of the liver (6)?
1) Stomach
2) Superior part of duodenum
3) Gall bladder
4) Lesser omentum
5) R colic fixture and transverse colon
6) R kidney and adrenal area
The liver is divided into left and right anatomically by the ________ but functionally by the __________.
Anatomically: Falciform ligament
Functionally: Fossae for gall bladder, IVC
Describe the blood supply of the liver.
1) Hepatic artery (20-25%): branch of celiac trunk
2) Portal vein (75-80%)
The portal vein is formed by the union of ___________ and ________.
Superior mesenteric vein and splenic vein
What are portal-systemic anastomoses?
Where veins draining to portal vein and IVC communicate
What happens to the portal vein is portal blood flow through the liver is obstructed?
It becomes dilated
What are 4 sites of portal-systemic anastomoses?
1) Esophageal (S) + L gastric (P)
2) Inferior rectal (S) + Superior rectal (P)
3) Epigastric (S) + Paraumbilical (P)
4) Retroperitoneal (S) +Visceral (P)
What are the 3 parts of the gall bladder?
1) Fundus
2) Body
3) Neck
Describe the blood supply of the gall bladder.
Cystic artery (branch of R hepatic artery)
Describe the innervation of the gall bladder.
Sympathetic: celiac plexus
- relaxation and pain
Parasympathetic: Vagus
- contraction and relaxation of sphincter of oddi
Passes in vicinity: R phrenic
- also supplies right shoulder area
The bile duct is formed by the joining of the ______ and the ______ (formed by union of ________ and _______)
R/L hepatic duct → common hepatic
Common hepatic + cystic duct → bile duct
Describe the position of the bile duct.
In front of portal vein, on right side of hepatic artery, in free margin of lesser omentum
The bile duct joins with the _______ and open into the _______ in the duodenal wall, which opens into the duodenum through the _______.
Bile duct + main pancreatic duct → open into ampilla of vater → open into duodenum via (major duodenal papilla)
The ampulla of vater and bile and pancreatic ducts are surrounded by circular muscle which functions as a _________________.
Sphincter of the bile duct
Describe the blood supply of the bile duct.
Proximal: Cystic artery
Hepatic: Middle
Duodenal part: Posterior Superior Pancreaticoduodenal and Gastroduodenal
Where would pain due to gallstones radiate to?
Right hypochondriac and right shoulder and neck
The spleen is completely covered with the peritoneum except at ______.
Its hilum (in contact with tail of pancreas)
What are the 2 connections (by ligament) of the spleen?
1) Greater curvature of stomach (by gastrosplenic ligament)
2) Left kidney (by splenorenal ligament)
What are the the relations of the spleen?
Anterior: stomach
Posterior: 9-11th rib, L diaphragm
Inferior: L colic flexure
Medial: L kidney
Tail of pancreas
The spleen receives blood from the __________, is drained by the ____________ and innervated by the ____________.
Splenic artery and vein
nerves of celiac plexus
How would fracture of the 9-11th rib affect the spleen?
Fracture → ↑intra-abdominal
pressure
→ rupture spleen
→ Severe intraperitoneal hemorrhage
Describe the position and bounds of the lesser sac (omental bursa).
Posterior to stomach and lesser omentum
Superior: diaphragm
Inferior: greater omentum
Left margin: spleen
The lesser and greater sac communicate through the _________________.
Omental foramen
The greater sac is divided by the ______________ into the ____________ and ________________.
Divided by transverse mesocolon into:
i) Supracolic compartment
ii) Infracolic compartment
What are the organs in the supracolic compartment of the greater sac?
Stomach, Liver, Spleen
What are the organs in the infracolic compartment of the greater sac?
Small intestine, colon
What are paracolic gutters?
Peritoneal compartments that lie on the lateral sides of the ascending and descending colons
The right paracolic gutter communicates with the _____________ which forms a route for infection to spread between the __________________________.
R paracolic gutter communicates with R subhepatic space
- communicates hepatorenal recess and pelvic cavity → infection spread from pelvis to upper abdomen
The left paracolic gutter is separated from the diaphragm by the ______________.
Phrenicocolic ligament
Is the pancreas retroperitoneal or intraperitoneal?
Retoperitoneal
The pancreas lies between which 2 organs?
Duodenum on right
Spleen on left
The uncinate process of the pancreas is located toward the (head/tail) of the organ?
Head
The main pancreatic duct opens into ___________ while the accessory duct opens into the __________.
Main → ampulla of vater
Accessory → duodenum
What are the relations of the pancreas (by its components)?
Head:
- descending duodenum
- common bile duct (posterior)
Neck
- Superior mesenteric vessels
- splenic vein (posterior)
Body:
- floor of omental bursa
- stomach (anterior)
- L kidney (posterior)
Tail:
- hilum of spleen
Uncinate process:
- Superior mesenteric vessels (anterior)
Describe the arterial supply of the pancreas?
Head:
- branches of gastroduodenal and superior mesenteric arteries
- superior and inferior pancreaticoduodenal arteries
Neck, body, tail:
- branches of splenic
What veins drain the pancreas?
Splenic and portal
The small intestines are composed of 3 segments: _____________________ and extend from the _______________ to the _______________.
1) Duodenum
2) Jejunum
3) Ileum
Pylorus of stomach → Ileocecal junction
What are the 4 segments of the duodenum?
1) Superior
- duodenal cap
- 5 cm, L1
- most duodenal ulcers
2) Descending
- 7-10cm, R of L1-3
- entrance to common bile duct (major duodenal papilla)
3) Inferior
- 6-8cm, crosses L3
4) Ascending
- 5cm, L2
Describe the arterial supply of the duodenum.
Branches of celiac and superior mesenteric artery
Above entry of bile duct:
- superior pancreaticoduodenal artery
Below/distal to major duodenal papilla:
- inferior pancreaticoduodenal artery
Describe the venous drainage of the duodenum.
Duodenal vein → portal vein
Describe the innervation of the duodenum.
Sympathetic:
- celiac plexus
- superior mesenteric plexus
Parasympathetic:
- vagus
Anterior duodenal ulcers erode _________to cause_____________.
Posterior duodenal ulcers erode _____________ to cause ________________.
Anterior erode peritoneum → peritonitis
Posterior erode gastroduodenal or posterior superior pancreaticoduodenal artery → haemorrhage
Most of the duodenum is (retro/intraperitoneal) while most of the jejunum and ileum is (retro/intraperitoneal).
Duodenum: most retroperitoneal
Jejunum and ileum: entirely intraperitoneal
Which abdominal quadrants are the jejunal and ileal loops located?
Jejunal: LUQ
Ileal: RLQ
The jejunum and ileum have circular mucosal folds (___________) except in the _________, where ___________ are frequent.
Circular folds: Plicae circulares
Except in terminal ileum (smooth)
- have peyer’s patches
What is the difference in morphology between the jejunum and ileum?
Jejunum:
- proximal 2/5
- Wide-bored, thick walled
- less prominent arterial arcades
- longer vasa recta
Ileum:
- distal 3/5
- smaller diameter, thin walled
- prominent arterial arcades
- shorter vasa recta
Describe the arterial supply of the jejunum and ileum.
Superior mesenteric artery
Describe the venous drainage of the jejunum and ileum.
Superior mesenteric vein → portal vein
Describe the nervous supply to the small intestine.
Sympathetic:
- celiac plexus
- superior mesenteric plexus
Parasympathetic:
- vagus
Sensory (sensitive to distension and nociceptive pain)
Describe the lymphatic drainage of the jejunum and ileum.
Lymphatics from walls → mesenteric lymph nodes → superior mesenteric nodes
How does a barium meal help in imaging?
used to detect abnormalities in GIT down till small intestine
- Barium sulfate (radio-opaque) coats lining of GIT (X-ray only highlight bone/radio-opaque tissues)
What are the main accessory features of the large intestine?
1) Omental appendices (appendices epiploicae/fatty tags)
2) Taenia coli
3) Haustra
The coecum is the first part of the large intestine and is located inferior to __________ opening and in the right ___________. It has no ___________ and has 3 bands of ______________.
Inferior to ileocecal opening and in the R iliac fossa
- no mesentery
- 3 bands of teniae coli
Where does the appendix arising from?
Midgut
The appendix is attached to the posteromedially to the ____________ and its base is located near the convergence of the __________ at the tip of the ___________, and has a short mesentery
Posteromedially to coecum
base near taeniae coli @ tip of coecum
Describe the innervation of the appendix.
Visceral sensory (pain) fibres accompany sympathetic nerve fibres and reach T10 sensory ganglia
What is the pathophysiology of the pain progression in worsening appendicits?
Initial: diffuse @ T10-11 dermatomes (umbilicus)
- visceral sensory accompany sympathetic → T10 ganglia → referred to T10 dermatome (umbilicus)
Worsened: Somatic L1 (right inguinal region)
- swelling of appendix → touch parietal peritoneum → irritate L1 somatic sensory nerve → sharp pain in right inguinal region (RLQ)
The ascending colon lies in the _____ quadrant and forms the ________ colic flexure.
It is supplied by the ____________ artery and innervated by ________________.
Ascending:
- RLQ
- forms right colic flexure
- suppled by right colic branches of SMA
- innervated by vagus and sympathetic
The descending colon is (retro/intraperitoneal), beginning at the _______ to end at the _________.
It is supplied by the ____________ artery and innervated by ________________.
Descending:
- splenic flexure → pelvic brim
- supplied by left colic branches of IMA
- Parasympathetic innervation by pelvic splanchnic nerve
The transverse colon is located in the ___________ region and extends from ______ to ______, suspending by the ____________.
It is supplied by the _________________ and innervated by ________________.
Transverse:
- umbilical region
- R to L colic flexures
- suspended by transverse mesocolon
- supplied by middle colic (from SMA) and left colic (from IMA)
- innervated by vagus (proximal 2/3) and pelvic splanchnic (distal 1/3)
The sigmoid colon is suspended by the ___________.
It is suppled by the _________________ and innervated by __________________.
Sigmoid colon:
- suspended by sigmoid mesocolon
- supplied by sigmoid branches of IMA
- innervated by lumbar part of sympathetic trunk and inferior hypogastric plexus (pelvic parasympathetic)
What organs does the coeliac trunk supply?
1) Foregut structures (down till major duodenal papilla)
2) Pancreas
3) Spleen
4) Liver
What are the branches of the superior mesenteric artery?
1) Inferior pancreaticoduodenal
2) Jejunal
3) Ileal
4) Ileocolic
5) Right colic
6) Middle colic
What are the branches of the inferior mesenteric artery?
1) Left colic
2) Sigmoid
3) Superior rectal artery
True or false: The right and middle colic arteries form an arterial anastomosis.
True
True or false: The left and middle colic arteries form an arterial anastomosis.
True
True or false: The left and right colic arteries form an arterial anastomosis.
False
What is the arterial anastomoses between the superior and inferior mesenteric artery?
Middle colic (branch of superior) and left colic (branch of inferior)
The lymphatic drainage of the bowel follows the (arterial/venous/nervous) supply?
Arterial supply
Where are the lymph nodes of the bowel groups and drain to?
Grouped around abdominal aorta
Drain to cisterna chyli
The cisterna chyli is an ___________________ located _______________ and is where the ___________ commences.
Cisterna chyli: elongated lymphatic sac
- located in front of L1/2 bodies
- where thoracic duct commences
Name the sympathetic (5) and parasympathetic sensory nerves of the GIT.
Sympathetic:
1) Greater thoracic splanchnic (T5-9)
2) Lesser thoracic splanchnic (T10-11)
3) Least thoracic splanchnic (T12)
4) Lumbar splanchnic (L1-2)
5) Sacral splanchnic (L1-2)
Parasympathetic:
1) Vagus (CN10)
2) Pelvic splanchnic (S2-4)
In the GIT viscera:
Sensory fibres running with the sympathetic mediate _________.
Sensory fibres running with the parasympathetic mediate ___________________.
Sensory w sympathetic: pain
Sensory w parasympathetic: reflex regulation
Describe the nervous supply to the large intestine.
Midgut portion (till 2/3 transverse colon):
Sympathetic: Superior mesenteric plexus (from T10-12)
Parasympathetic: Vagus
Hindgut portion:
Sympathetic: Inferior mesenteric plexus (from L1-2)
Parasympathetic: Pelvic splanchnic (L1-2)
The rectosigmoid junction lies at which vertebra level?
S3
The rectum follows the curve of the sacrum and the coccyx, forming the ________.
It ends anteroinferior to the tip of the coccyx where it turns posteroinferiorly and becomes the _____________, forming the _________ as it perforates the pelvic diaphragm.
Rectum:
Curve of sacrum + coccyx → sacral flexure
Sharp posterior bend at tip of coccyx → anorectal flexure → anal canal
The dilated terminal part of the rectum (________________) supports and retains fecal mass before expulsion, when the relaxation of the _____________ muscle results in straightening of the anorectal junction.
Ampulla of rectum
relaxation of puborectalis muscle → straighten anorectal junction
What are the 5 flexures of the rectum?
Proximal to distal:
1) Sacral (curve of sacrum and coccyx)
2) Anorectal (tip of coccyx)
3) Superior lateral
4) Intermediate lateral
5) Inferior lateral
Which parts of the rectum does the peritoneum cover?
Superior 1/3: Anterior and lateral surface
Middle 1/3: Anterior
Inferior 1/3: none (subperitoneal)
Lateral reflections of the peritoneum from the superior 1/3 of the rectum form __________ which permits the rectum to distend as it fills with feces.
Pararectal space/fossae
Describe the relations of the rectum.
Posterior: S2-4, coccyx, anococcygeal ligament, median sacral vessels, inferior ends of sympathetic trunk and sacral plexuses
M:
Anterior: fundus of bladder, terminal uterus, vas deferens, seminal vesicular glands, prostate
F:
Anterior: Vagina, rectouterine pouch
Describe the arterial supply of the rectum.
Proximal rectum: Superior rectal artery (branch of inferior mesenteric)
Middle and inferior rectum: R/L middle rectal arteries (branch of inferior vesical (M) or uterine (F))
Anorectal junction and anal canal: Inferior rectal artery (branch of internal pudendal arteries)
Describe the venous supply of the rectum.
Follows arteries of same name
Superior rectal vein → inferior mesenteric vein → portal system
Middle and inferior vein → internal iliac vein → IVC
What is 1 important area of portocaval anastamosis?
Rectum:
Superior rectal vein → inferior mesenteric vein → portal system
Middle and inferior vein → internal iliac vein → IVC (systemic)
Describe the lymphatic drainage of the rectum.
Superior 1/2: Pararectal lymph nodes → inferior mesenteric lymph nodes
Inferior 1/2: Sacral lymph nodes → internal iliac lymph nodes
Describe the nervous supply of the rectum.
Sympathetic: Lumbar splanchnic nerves (L1-2)
Parasympathetic: Pelvic splanchnic nerves from sacral (S2-4)
Visceral afferent:
Above pain line: follow sympathetic to L1-2 spinal sensory ganglia
Below pain line: follow parasympathetic retrogradely to S2-4
What are some physiological and pathological structures that can be palpated in a digital rectal exam?
Physiological:
1) Prostate and seminal glands (M)
2) Cervix (f)
3) Pelvic surfaces of sacrum and coccyx
4) Ischial spine and tuberosity
Pathological
1) Enlarged internal iliac lymph nodes
2) Pathological thickening of ureters
3) Swelling in ischioanal fossae
4) Tenderness of inflamed appendix
The anal canal begins at the ___________ and ends at the _____________________.
Begins: where ampulla of rectum abruptly narrows (at level of sling formed by puborectalis)
Ends: external outlet of ailmentary tract
Defecation can only other when both anal sphincters ____________ of which they are _____________________________ and innervated by ________________________________.
Both need to relax
External: voluntary (S4 through inferior rectal nerve)
Internal: involuntary (inferior hypogastric plexus)
The anal canal is divided into 2 by the _________________, where there are ______________ and ________________ superior to them.
Anal canal divided by pectinate line (inferior comb-shaped limit of anal valves).
- where anal valves meet anal columns (in superior 1/2) and there are anal sinuses (exude mucus)
How do the superior and inferior halves of the anal canal differ in their embryological origin?
Superior: hindgut
Inferior: Embryonic proctodeum
Describe the arterial supply of the anal canal.
Superior: superior rectal artery (from inferior mesenteric)
Inferior: 2 inferior rectal arteries (internal pudendal from internal iliac)
Middle rectal arteries: form anastomoses w superior and inferior rectal arteries
Describe the venous drainage of the anal canal.
Entirely by internal rectal venous plexus but:
Superior 1/2 → superior rectal vein → inferior mesenteric → portal system
Inferior 1/2 → inferior rectal vein → internal pudendal → caval venous system
Muscularis externa of rectal ampulla: middle rectal veins (from anastomoses w superior and inferior rectal veins)
What are the difference between internal and external hemorrhoids?
External:
- thromboses in veins of external rectal venous plexuses
- predisposing factors (eg. pregnancy, chronic constipation, anything that ↓venous return)
Internal:
- prolapses of rectal mucosa w normally dilated veins of internal rectal venous plexus
- by breakdown of Muscularis mucosae
- compressed by contracted sphincters → ↓blood flow → ulcerate → bleed bright red
How would portal hypertension affect the rectal veins?
Portal hypertension → ↑P on portocaval anastomoses (superior, middle, inferior rectal veins) → varicose
Describe the lymphatic drainage of the anal canal.
Superior 1/2: Internal iliac lymph nodes → common iliac and lumbar lymph nodes
Inferior 1/2: Superior inguinal lymph nodes
How does sensory reception differ along the anal canal?
Superior 1/2: Visceral afferent → insensitive to sharp pain, only sensitive to stretching
Inferior 1/2: Somatic sensory → sensitive to sharp pain, touch, temperature
How are internal haemorrhoids treated?
Rubber band ligation
The abdominal aorta begins at ______ level and bifurcates into ___________________ at ________ level, from which they each divide into the ______________ at _________. Adjacent to the abdominal are __________________________.
T12 (diaphragm) → R/L common iliac (L4) → Internal/external iliac (L1-3 sacroiliac joint)
Adjacent vessels:
R: IVC, Cisterna chyli, azygos vein
L: sympathetic trunk
The inferior vena cava is formed by the union of _____________ at _____ level and ascends (right/left) of the abdominal aorta to pass through the __________, into the thorax and drain into the right atrium.
Formed @ union of common iliac veins (L5) → Right of abdominal aorta → pass through caval foramen (diaphragm at T8)
