GIT anatomy Flashcards

1
Q

What makes up the foregut?

A

Distal 3rd of esophagus to the 2nd part of the duodenum at the entrance of the bile duct (Major duodenal papilla - where ampulla of vater opens through)

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2
Q

What makes up the midgut?

A

2nd part of the duodenum to proximal 2/3rd transverse colon

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3
Q

What makes up the hindgut?

A

Distal 1/3rd of transverse colon to the rectum

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4
Q

What are the 9 regions of the abdomen?

A

R & L hypochondrium, epigastric
R &L flank, umbilical
R & L groin, pubic (hypogastric)

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5
Q

What are the planes?

A

Transpyloric L1
Subcostal L3
Intertubercular L5

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6
Q

Abdominal wall fascia from surface to deep?

A
  1. Skin
  2. Superficial fascia
    1. Camper fascia
    2. Scarpa fascia
  3. Investing fascia
    1. Superficial > External oblique muscle
    2. Intermediate > Internal oblique muscle
    3. Deep > Transverse abdominis muscle
  4. [Deep] Transversalis fascia
  5. Extraperitoneal fat
  6. Parietal peritoneum
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7
Q

Above umbilicus of rectus sheath?

A
  • Internal oblique aponeurosis split and encloses the rectus abdominis
  • External oblique aponeurosis is in front RA
  • Transversus abdominis behind RA
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8
Q

Below umbilicus of rectus sheath

A

all 3 layers anterior to rectus muscle

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9
Q

Arcuate line?

A
  • Anterior wall is complete
  • Posterior wall is incomplete. Stops short below umbilicus at arcuate line
  • Below arcuate line, rectus abdominis in contact with transversalis fascia
  • Arcuate line demarcates the transition between Posterior wall cover superior 3 quarters of rectus abdominis & transversalis fascia cover inferior quarter
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10
Q

How is conjoint tendon formed?

A

Lowest fibres of internal oblique and transverse abdominis join to form the Conjoint tendon

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11
Q

How is superficial inguinal ring formed?

A

Aponeurosis of external oblique fuses medially with rectus sheath to form superficial inguinal ring (hole in EOA)

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12
Q

How is inguinal ligament formed?

A

Lower external oblique aponeurotic edge curls under to form inguinal ligament

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13
Q

Where does neurovascular plane lie?

A

between internal oblique & transversus abdominis

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14
Q

Arterial supply of rectus abdominis?

A
  • 2 vessels enter rectus sheath & anastomose → possible by-pass to abdominal aorta
  1. Superior epigastric* (from internal mammary thoracic)
  2. Inferior epigastric* (from external iliac)
  • These arteries are posterior to rectus abdominis, but within rectus sheath
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15
Q

Dermatomes?

A
  • T7-T9 – epigastrium
  • T10 – umbilicus
  • T11-12 – inferior to the umbilicus
  • L1 (IlioHypogastric N, IlioInguinal N) – inguinal & pubis
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16
Q

Whats the inguinal canal?

A

Groin between ASIS (anterior superior iliac spine) & pubic tubercle
from Deep Inguinal Ring to Superficial Inguinal Ring

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17
Q

DIR vs SIR?

A

DIR : hole in transversalis fascia
SIR : hole in EOA

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18
Q

Difference in contents in inguinal canal between male & female?

A

Male : spermatic cord
Female : round ligament

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19
Q

4 walls of inguinal canal - 2 MALT

A
  1. [Roof]
    2 Muscles:Transversus abdominis,internal oblique
  2. [Anterior wall]
    2Aponeuroses:Internal oblique aponeurosis,external oblique aponeurosis
    3.[Floor]
    2Ligaments:Inguinal ligament,lacunar ligament
  3. [Posterior wall]
    2Tendon:Conjoint tendon medially,Transversalis fascia laterally
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20
Q

Mid-inguinal point VS Mid-point of inguinal ligament?

A

Mid-inguinal : half-way between ASIS & pubic symphysis
- Femoral artery in groin

Mid-point : between ASIS & pubic tubercle
- DIR
- indirect inguinal hernias

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21
Q

4 types of hernias?

A
  1. Reducible → sac returns to containing cavity
  2. Irreducible → can’t be returned to containing cavity
  3. Obstructed → contains blocked bowel
  4. Strangulated → contents with a compromised blood supply → possible gangrene
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22
Q

Factors that prevent occurrence of hernia?

A
  1. Oblique passage
  2. Posterior wall (immediately behind the superficial inguinal ring) is reinforced by the conjoint tendon
  3. When intra-abdominal pressure is increased on coughing and straining, the roof compresses the contents of the canal against the floor, so that the canal is completely closed (contents cannot be herniated!)
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23
Q

Direct vs indirect (inguinal) hernia?

A

Landmark to differentiate : Inferior epigastric artery

medial to IEA - direct
lateral to IEA - indirect

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24
Q

inguinal vs femoral hernia?

A

femoral : below & lateral to public tubercle.
VS inguinal : above & medial

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25
Q

Branches of abdominal aorta

A

Celiac trunk T12
SMA L1
IMA L3

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26
Q

Branches of celiac trunk

A
  1. Left gastric
  2. Common hepatic -> right gastro-omental, right gastric, superior pancreaticoduodenal
  3. Splenic -> left gastro-omental, short gastric
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27
Q

Portal-Systemic anastomoses [PSA] (4 sites)

A

A. Lower esophagus
- Left gastric (P)
- Esophageal (S)

B. Rectum
- Superior rectal (P)
- Inferior rectal (S)

C. Umbilicus
- Paraumbilical (P)
- Epigastric -> Ext. iliac (S)

D. Posterior abdominal wall
- Visceral (P)
- Retroperitoneal (S)

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28
Q

Peritoneum of males vs females

A

Males : completely closed
Females : incompletely closed - potential pathway for infection

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29
Q

Where is the lesser & greater omentum?

A

L : between liver & lesser curvature of stomach
G : between greater curvature & tranverse colon

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30
Q

Where does portal triad run?

A

Portal triad : portal vein, hepatic artery, bile duct
Near free edge of lesser omentum

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31
Q

2 ligaments of lesser omentum? & greater?

A

L :
Hepatogastric
Hepatoduodenal

G;
Gastrophrenic
Gastrosplenic

32
Q

Whats omental foramen?

A

Lesser sac & greater sac communicate through omental foramen

33
Q

How is greater sac divided?

A

Divided by Transverse mesocolon into :
1. Supracolic compartment (Above TM)
- Liver, Stomach, Pancreas, Spleen

  1. Infracolic compartment (Below TM)
    - Small intestines, Colon
34
Q

Boundaries of lesser sac? (omental bursa)

A
  • anterior : stomach & lesser omentum
  • superior : diaphragm
  • inferior : layers of greater omentum
  • left margin formed by spleen
35
Q

Boundaries of omental foramen / foramen of Winslow

A
  1. Anterior: bile duct, hepatic artery & portal vein [portal triad]
  2. Posterior: IVC & diaphragm
  3. Superior: caudate lobe of the liver
  4. Inferior: first part of the duodenum
36
Q

What organs are INTRAperitoneal?

A

Stomach
Liver
Spleen
Pancreas (tail)
Duodenum (1st part)
Ileum, Jejunum
Colon (cecum, transverse, sigmoid)

37
Q

What organs are RETROperitoneal

A

Duodenum (2nd-4th part)
Pancreas (head, body, neck)
Colon (ascending, descending)
Kidneys, great vessels, oesophagus, rectum

38
Q

2 orifices of stomach?

A

Cardiac (gastroesophageal junction)
Pyloric (gastroduodenal junctin)

39
Q

Impt posterior relations of stomach from superior to inferior?

A
  1. Spleen
  2. Left suprarenal gland
  3. Splenic artery
  4. Pancreas
  5. Tr colon
  6. Kidney
40
Q

Arterial supply of stomach?

A

Lesser curvature
- Left gastric & right gastric (common hepatic) anastomoses

Greater curvature
- Right gastro-omental (common hepatic) & Left gastro-omental (splenic) anastomoses

Fundus & upper part of greater curvature
- Short gastric (splenic)

41
Q

Sympathetic innervation of stomach?

A

from t5-t9 spinal segments

42
Q

Recesses & surfaces of liver?

A

Subphrenic recess, hepatorenal recess

Diaphragmatic & visceral surface

43
Q

3 Ligaments of liver & attachment

A
  1. Falciform ligament → anterior abdominal wall
  2. Hepatogastric ligament → stomach
  3. Coronary ligament → Diaphragm
44
Q

Anatomical vs functional lobes of liver

A

Anatomical
- divided by falciform ligament
- Right anatomical lobe : Quadrate lobe + Caudate lobe

Functional
- divided by fossae for gall bladder & IVC
- Left functional lobe : Quadrate lobe + Caudate lobe

45
Q

Where can gallbladder be palpated

A

Tip of right 9th costal cartilage (around L1)

46
Q

How is neck of gallbladder connected to common BD?

A

Cystic duct connects the neck to the common bile duct

47
Q

Arterial supply of gallbladder?

A

Cystic artery (branch of right hepatic from common hepatic)

48
Q

Where is gallbladder referred pain?

A
  • Right phrenic nerve irritated
  • Local pain in right hypochondriac area
  • Referred pain → Right shoulder / neck
  • C3-C5 dermatomes
  • EG biliary colic
49
Q

What makes the bile duct?

A
  • R + L hepatic ducts → common hepatic duct
  • common hepatic duct + cystic duct → bile duct
50
Q

Ampulla of vater?

A
  • BD joins with main pancreatic duct → open into the ampulla of vater in the duodenal wall
  • Ampulla of vater opens into the duodenum through major duodenal papilla
51
Q

Sphincter of Oddi

A

Ampulla of vater, bile & pancreatic ducts are surrounded by circular muscle → sphincter of Oddi

By parasympathetic innervation

52
Q

Relations of spleen?

A
  • Anterior : stomach
  • Posterior : T9-11 & Left diaphragm
    • Fracture of T9-11 ribs may rupture spleen / sudden increase in intra-abdominal pressure too → Severe intraperitoneal haemorrhage
  • Inferior : Left colic flexure
  • Medial : Left kidney
  • Hilum : (in contact with) Tail of pancreas
53
Q

Ligaments of spleen & attachments?

A
  1. Gastrosplenic ligament → Greater curvature of stomach
  2. Splenorenal ligament → Left kidney
54
Q

Where does pancreatic duct open into?

A
  • Main pancreatic duct → ampulla of vater
  • Accessory pancreatic duct → duodenum
55
Q

Relations of pancreas?

A
  1. Head
    1. attached to descending part of duodenum
    2. posterior : common bile duct
    3. tumour in head least likely to compress spleen
  2. Neck
    1. posterior : superior mesentric vessels & splenic vein
    2. tumour in neck most likely to obstruct portal vein
  3. Body
    1. floor of omental bursa
    2. anterior : stomach
    3. posterior : left kidney
  4. Tail
    1. hilum of spleen
  5. Uncinate process
    1. anterior : superior mesentric vessels
56
Q

Arterial supply of pancreas?

A

Head :
- Superior / Inferior pancreatico duodenal arteries from gastroduodenal (common hepatic) & SMA respectively
-> Anastomoses

Neck, Body, Tail
- Branches of Splenic

57
Q

Venous drainage of pancreas?

A

Splenic & portal vein

58
Q

Referred pain of duodenal ulcer?

A

if Anterior → Peritonitis (erosion of peritoneum)

Right shoulder pain if fluid leak into peritoneal cavity & touch diaphragm as phrenic nerve (C3-C5) is irritated

59
Q

Jejunum vs Ileum

A

Ileum
1. Thinner walls
2. Longer
3. Prominent arterial arcades
4. Shorter vasa recta
5. Terminal : no plicae circulares
6. Have Peyer’s patches

60
Q

Arterial supply of jejunum & ileum?

A

SMA - jejunal arteries & ileal arteries
Terminal ileum : ileocolic artery

61
Q

Innervation of small intestines?

A

Sympathetic : greater splanchnic
Parasympathetic : Vagus

62
Q

Main features of colon?

A
  1. Omental appendices
  2. Omental tenia coli
  3. Haustra
63
Q

Innervation of appendix? Hence, Appendicitis pain?

A

Early

  • Visceral (diffuse) pain → referred to T10 dermatome (umbilicus)
  • sensory fibres accompany sympathetic nerve fibres & reach T10 spinal sensory ganglia

Late

  • Sharp pain in right inguinal region
  • Swelling of appendix → Touch parietal peritoneum → L1 spinal nerve irritated
  • Somatic sensory which supply skin to inguinal region
64
Q

Arterial supply of colon

A
  1. ascending : right colic (SMA)
  2. transverse : middle colic (SMA), left colic (IMA)
  3. descending : left colic (IMA)
  4. sigmoid : sigmoid (IMA)

anastomosis between right & middle colic. then middle & left colic

65
Q

Whats the cisterna chyli

A
  • All lymph drains into the cisterna chyli
    • cc : an elongated lymphatic sac located in front of the L1 & L2 bodies (transpyloric plane ish)
    • Thoracic duct commences from cc
66
Q

What’s anorectal flexure?

A

Impt for fecal continence & is maintained during the resting state by the tonus of the puborectalis muscle
+ its active contraction during peristaltic contractions if defecation is not to occur

67
Q

What’s ampulla of rectum for?

A

Dilated terminal part, the ampulla of the rectum, supports and retains the fecal mass before it’s expelled during defecation

68
Q

Arterial supply of rectum?

A
  • Superior rectal artery (from IMA) → proximal part of the rectum
  • R & L middle rectal arteries [from the inferior vesical (male) or uterine (female) arteries] → middle & inferior parts of the rectum
  • Inferior rectal arteries [from the internal pudendal arteries] → anorectal junction & anal canal
69
Q

Innervation of rectum

A
  • Rectum above the pelvic pain line : visceral afferent fibers follow the sympathetic fibers to the L1–L2 spinal sensory ganglia
    • Sympathetic : lumbar spinal cord, via lumbar splanchnic nerves (L1 – L2)
  • Rectum below the pelvic pain line : visceral afferent fibers follow the parasympathetic fibers retrogradely to the S2–S4 spinal sensory ganglia
    • Parasympathetic : sacral spinal cord, via the pelvic splanchnic nerves (S2–S4)
70
Q

Pectinate line ( impt in surgery)

A

Superior : visceral afferent nerves
- painless

Inferior : somatic sensory
- sensitive
- explains pain after rubber band ligation (treatment for internal hemorrhoids)

71
Q

Internal vs external hemorrhoids

A

Internal ->
- inside rectum, above pectinate line.
- bleeding (bright red) but painless
- feeling of incomplete evacuation

External ->
- under skin around anus
- could develop blood clots -> severe pain & swelling

72
Q

Sensory fibres? (by ANS)

A

Sympathetic sensory (pain)
1. Thoracic splanchnic (T5-12)
- FG (5-9)
- MG (10-12)
2. Lumbar splanchnic (L1+L2)
- HG

Parasympathetic (regulate reflex gut function)
1. Vagus nerve (up to proximal 2/3 of transverse colon)
2. Pelvic splanchnic nerves (S2-S4) -> Distal 1/3 of transverse colon onwards
[HG]

73
Q

Venous drainage of biliary tree + pancreas + spleen?

A

Portal vein -> Liver -> Hepatic vein -> IVC

74
Q

Functions of liver?

A
  1. Production of cholesterol
  2. Storage of micronutrients
  3. Blood sugar balance
  4. Production of bile
  5. Protein synthesis
  6. Immune system
  7. Metabolism
  8. Detoxification
75
Q
A