Anatomy Flashcards
Epigastric
Upper middle ninth
Hypochondrium
Left and right upper ninths
Umbilical
Middle ninth
Flank
Left and right middle ninths
Pubic
Lower middle ninth
Groin
Left and right lower ninths
9 layers of abdominal wall from skin to abdominal cavity
Skin Campers fascia Scarpas fascia External oblique muscle Internal oblique muscle Transversus abdominis Transversalis fascia Extraperitoneal fascia Parietal peritoneum
Superior boundary of abdomen
Diaphragm and inferior thoracic aperture
Inferior boundary of abdomen
Iliac crest, inguinal ligament and pelvic inlet
Posterior boundary of abdomen
Lumbar vertebral column, psoas major, quadratum lumborum
Lateral and anterior boundary of abdomen
Abdominal wall muscles
Above the bellybutton, the fascia present is:
Campers fascia only
Below the bellybutton, the fascia present is:
Campers and Scarpas fascia
Campers fascia
Thick, fatty superficial layer of the anterior abdominal wall
Scarpas fascia
Deep membranous layer of fascia
Deep to Campers fascia, superficial to external oblique muscle
Rectus abdominis origin
Pubic tubercle, crest and symphysis
Rectus abdominis insertion
Costal cartilage of ribs 5 - 7 and xiphoid process
Rectus abdominis actions
Flexes trunk
Supports and compresses abdominal wall
Rectus abdominis innervation
Anterior rami of thoracic spinal nerves
Rectus abdominis fibre direction
Directly down
External oblique origin
Ribs 5 - 12
External oblique insertion
Iliac crest and linea alba
Aponeurosis of external oblique muscle
From xiphoid process of sternum to pubic symphysis. Lower border forms inguinal ligament.
External oblique actions
Flexes trunk
Turns to opposite side
Bends to same side
External oblique innervation
Anterior rami of thoracic spinal nerves
External oblique fibre direction
Infero-medial
Linea alba
Fibrous structure that runs down the midline of the abdomen in humans and other vertebrates
Internal oblique origin
Thoracolumbar fascia, inguinal ligament and iliac crest
Internal oblique insertion
Ribs 9 - 12, linea alba and pubis
Internal oblique actions
Flexes trunk
Bends and turns trunk to the same side
Internal oblique innnervation
Anterior rami of thoracic spinal nerves
Some L1
Internal oblique fibre direction
Supero-medial
Transversus abdominis origin
Thoracolumbar fascia, iliac crest, inguinal ligament and costal cartilage of ribs 7 - 12
Transversus abdominis insertion
Linea alba, pubic crest and pectineal line
Transversus abdominis actions
Supports abdominal wall
Transversus abdominis innervation
Anterior rami of thoracic spinal nerves
Some L1
Transversus abdominis fibre direction
Transverse
Below the arcuate line there is no:
Posterior rectus sheath behind rectus abdominis
Instead covered posteriorly by transversalis fascia and parietal peritoneum
The superior epigastric artery comes from:
The internal thoracic artery
The inferior epigastric artery comes from:
The external iliac artery
Position of superior and inferior epigastric arteries
Deep longitudinally to rectus abdominis, on top of transversalis fascia and within the rectus sheath
Eventually form an anastamosis
The thoracoepigastric veins drain into:
The axillary vein
The superficial epigastric veins drain into:
The femoral vein
The axillary vein drains:
The superior abdomen
The femoral vein drains:
The inferior abdomen
Abdominal nerve position
Travel in neurovascular plane between internal oblique and transversus abdominis muscles
Skin, muscles and parietal peritoneum innervation
T7 - T12 intercostal and L1 iliohypogastric spinal nerves
Important landmark of the T10 dermatome
Umbilicus
Important landmark of the T4 dermatome
Nipple
In general, the superior lymphatics follow:
Veins
In general, the inferior lymphatics follow:
Arteries
Visceral peritoneum covers:
Organs (abdominal viscera)
Parietal peritoneum:
Lines the body wall
Between the two peritoneum layers you can find:
A small amount of serous fluid to prevent friction during movement
Mesentery is formed by:
The visceral peritoneum folding back in on itself, forming an anchor to the posterior body wall
Function of mesentery
Anchorage
Passage of blood vessels and nerves in and out
Parietal peritoneum sensation
Sensitive to pain, touch, temperature and pressure
Thoracic and lumbar somatic nerves supply body wall
Phrenic nerve supplies near diaphragm
Obturator nerve supplies near pelvis
Visceral and mesentery sensation
Sensitive to stretch by autonomic nervous system
GI tract is suspended by:
Multiple mesenteries
Midgut and hindgut is suspended by:
Dorsal mesentery only
Foregut is suspended by:
Both ventral and dorsal mesenteries
Greater sac
Peritoneal cavity proper
Lesser sac
Behind lesser omentum and stomach
Formed by rotation of foregut structures which drags the lesser omentum round to create a pocket
The opening to the lesser sac is called:
The foramen of Winslow
Boundaries of the foramen of Winslow
Anterior: the free edge of the lesser omentum containing the portal triad
Posterior: the IVC
3 intraperitoneal areas suspended by mesenteries
Jejunum to terminal ileum - mesentery
Transverse colon - transverse mesentery
Sigmoid colon - sigmoid mesocolon
Paracolic gutter
Peritoneal sulci lateral to the ascending/descending colons
Create a pathway for fluids to migrate around the abdomen
Clinical significance of paracolic gutter
Different positions of the body can affect fluid migration which can cause pain to present in different regions distant from the affected organ
A sitting position causes fluid to migrate down towards appendix, a spine position causes fluid to migrate into lesser sac
Abdominal aorta branches
Celiac trunk at T12/L1 level
Superior mesenteric artery at L1 level
Inferior mesenteric artery at L3 level
Bifurcation at L4 leading to left and right common iliac arteries
3 branches from the celiac trunk
Left gastric artery
Splenic artery
Common hepatic artery
Injury to foregut localises pain at the:
Epigastric region
Components of the foregut
Distal oesophagus Stomach Liver Gall bladder Proximal 1/3 of duodenum Pancreas
Foregut blood supply
Branches of the celiac trunk
Foregut venous drainage
The portal vein
Foregut innervation
Celiac plexus at T12
Foregut lymphatics
Pre-aortic nodes at T12 (celiac nodes)
Fundus location
Ribs 5/6
Oesophagus location
Costal cartilage 7/8
Pylorus location
L1 verterbral level
Lesser curvature arterial supply
Left gastric - celiac trunk
Right gastric - common hepatic artery
Greater curvature arterial supply
Left gastro-omental - splenic
Right gastro-omental - gastroduodenal and common hepatic arteries
Fundus arterial supply
Splenic artery
Duodenal structure
Originates from pyloric region of stomach and wraps around head of pancreas. Then crosses back over IVC and aorta and ascends to duodenojejunal flexure.
Mostly retroperiotoneal except for the very first part
Duodenal blood supply
Part celiac trunk, part super mesenteric artery
Superior half = superior pancreaticoduodenal branches from gastroduodenal artery of celiac origin
Inferior half = inferior pancreaticoduodenal branches from superior mesenteric artery
Duodenal innervation
Superior half: celiac plexus at T12
Inferior half: superior mesenteric plexus at L1
Duodenal venous drainage
Superior half: direct to portal vein
Inferior half: superior mesenteric vein
Duodenal lymphatic drainage
Superior half: Pre-aortic celiac nodes at T12
Inferior half: Pre-aortic superior mesenteric nodes at T1
Ampulla of Vater
Union of common bile duct and main pancreatic duct which drains into descending duodenum
Major duodenal papilla
Enters through wall of descending duodenum
Controls bile flor from liver and pancreatic juice from pancreas into the duodenum via the Sphincter of Oddi
Sphincter of Oddi
Clamps off major duodenal papilla to stop bile constantly dripping in
Midgut refers to pain in the:
Umbilical region
Components of midgut
Distal 1/2 duodenum Jejunum Ileum Caecum Appendix Ascending colon Proximal 2/3 transverse colon
Neurovascular structures of midgut
Arterial: branches of SMA
Venous: SMV
Innervation: SM plexus at L1
Lymphatics: Pre-aortic nodes at L1
Small intestine anatomy
About 6 m long
Suspended from body wall by mesentery, fan shaped folds of peritoneum enclosing the gut tube allowing ingress and egress of vessels, nerves and lymphatics
Haustra
Sacculations of the large intestine wall
Appendices epiplociae
Pouches of peritoneum in the large intestine filled with fat that can get inflamed
Teniae coli
Longitudinal muscles of the large intestine wall collected into 3 bands that can contract, pulling the colon into haustra coli
Caecum and appendix region
Right groin
Large intestine is found in all gut regions except:
Umbilical
3 flexures of large intestine
Hepatic
Splenic
Sigmoid colon
Regions that flexures are found in
Hepatic - Right hypochondrium
Splenic - Left hypochondrium
Sigmoid colon - Left groin
Superior mesenteric arteries supplying the large intestine
Caecum/appendix: caecal and appendicualr arteries respectively, both from ileocolic artery
Ascending colon: right colic artery
Proximal 2/3 transverse colon: middle colic and marginal arteries
Inferior mesenteric arteries supplying the large intestine
Distal 1/3 transverse colon: marginal and left colic arteries
Descending colon: left colic artery
Sigmoid colon: sigmoid artery
Marginal artery
Anastomotic point between SMA and IMA
Neurovascular structures of hindgut
Arterial supply: branches of IMA at L3
Innervation: IM plexus at L3
Venous: IMV
Lymphatics: pre-aortic inferior mesenteric nodes at L3
Sigmoid colon becomes rectum at:
S3 vertebral level
Stool is held in the:
Transverse folds of the rectum
Rectal peritoneum
1st 1/3: Covered in visceral peritoneum
2nd 1/3: Peritoneum on anterior surface only
3rd 1/3: Infraperitoneal
Arterial supply of rectum
Superior rectal branches of IMA at L3
Middle rectal branch of internal iliac artery
Inferior rectal branch of internal pudendal
Venous drainage of rectum
Superior rectal vein —-> IMV —-> portal vein
Middle and inferior rectal veins —-> internal iliac vein —-> common iliac artery —-> IVC
Innervation of rectum
Proximal 1/3: IMP at L3
Distal 2/3: Inferior/superior hypogastric plexus
Lymphatics of rectum
Proximal 1/3: to pre-aortic nodes at L3
Distal 2/3: to internal iliac nodes
Parasympathetic nerve supply of the gut
Vagus nerve
Pelvic splanchnic nerves S2-4
Sympathetic nerve supply of the gut
Thoracic, lumbar and sacral splanchnic nerves from T5-L2 sympathetic ganglia
Foregut autonomic supply
Plexus: Celiac
SNS: Greater splanchnic T5-9
PSNS: Vagus X
Midgut autonomic supply
Plexus: Superior mesenteric
SNS: Lesser splanchnic T10-11
PSNS: Vagus X
Aorticorenal autonomic supply
Plexus: Renal
SNS: Least splanchnic T12
PSNS: Vagus X
Hindgut autonomic supply
Plexus: Inferior mesenteric and superior hypogastric
SNS: Lumbar/sacral splanchnic fibres L1-2
PSNS: Pelvic splanchnic S2-4
Pelvic organs autonomic supply
Plexus: Inferior and superior hypogastric
SNS: Sacral splanchnic L1-2
PSNS: Pelvic splanchnic S2-4
Location of liver
Right hypochondrium, extends into epigastric region
Superior boundary of liver
Ribs 5/6
Gall bladder location
9th costal cartilage level, affixed to bottom of liver
Gross morphology of liver
2 lobes on anterior surface separated by falciform ligament
4 lobes on posterior surface: back of left and right lobes, caudate lobe in middle and quadrate lobe below (continuation of right lobe)
Gall bladder between quadrate lobe and right lobe on posterior surface, IVC between caudate lobe and bare area above right lobe
Bare area of liver
Only part of the liver not intraperitoneal. Functions to anchor liver to diaphragm
Quadrate lobe
Anatomically part of right lobe but separated from the rest of the lobe by the gall bladder, therefore considered its own area
Falciform ligament
Separates right and left lobes on anterior surface. Remnant connecting to body wall containing ligamentum teres
Ligamentum teres
Runs inside and extends out of the falciform ligament. Embryological remnant of umbilical cord.
Porta hepatis
Doorway to liver
Free edge of lesser omentum attaches here
Portal triad runs through here
Portal triad
Portal vein
Hepatic artery
Common hepatic duct
The liver is covered in visceral peritoneum except for:
Bare area and fossa for gall bladder
6 peritoneal ligaments
Right triangular ligament Anterior coronary ligament Left triangular ligament Falciform ligament Posterior coronary ligament Hepatoduodenal ligament
Pouch of Morison
Space that separates the liver from the right kidney, normally not filled with fluid
Blood supply to liver
25% hepatic artery proper supplies oxygenated blood
75% portal vein supplies nutrient rich blood
Venous drainage of liver
Arterial and venous blood conducted to central vein of each liver lobule by sinusoids, then central veins drain to left, right and central hepatic veins, then directly into IVC
Liver segments
Determined by position of hepatic and portal veins
Caudate lobe is I, rest numbered clockwise from top right corner
Falciform ligament separates lobes II and III from rest of liver
No arterial communications between right and left halves
2 x portal veins
3 x hepatic veins
Lymphatic drainage of liver
Lymph from liver about 1/3 total body lymph
Nodes at porta hepatis to celiac nodes at T12
ANS of liver
Visceral supply from celiac plexus
PSNS via vagus nerve, SNS from greater splanchnic nerves T5-9
Pain in liver
Referred to epigastric region
Small amount via diaphragm to right shoulder/chest (C3-5)
Gross morphology of gallbladder
Fundus hangs below liver
Body contacts visceral surface of liver
Neck joins cystic duct
Covered in visceral peritoneum
Biliary tree
Bile secreted by liver, stored by gallbladder
When released, bile flows down cystic duct into common hepatic duct where it is joined by main pancreatic duct
Drained via bile duct which bifurcates past cystic duct into left and right hepatic ducts
Hepatopancreatic ampulla of Vater
Formed by the union of the pancreatic duct and common bile duct
Opens into duodenum via sphincter of Oddi
Neurovascular structures of gallbladder
Arterial supply: cystic artery from right hepatic artery
Venous drainage: cystic vein into portal vein
Innveration: ANS via celiac plexus, pain referred to epigastric region
Lymphatics: cystic nodes to hepatic nodes to celiac nodes at T12
Gallstones
Crystalline bodies made from bile components
Cholesterol = green or yellow/white
Pigment stones = small, dark calcium or bilirubin stones
5 areas of pancreas
Head - in concavity of duodenum Ulcinate process - wraps behind SM vessels Neck - anterior to SM vessel origins Body Tail - passes into splenorenal ligament
The tail of the pancreas is in contact with:
The hilus of the spleen
Main pancreatic duct
From tail to Ampulla of Vater
Joined by bile duct
Enters descending duodenum via Sphnicter of Oddi (major duodenal papilla)
Accessory pancreatic duct
Not always present
Drains into upper part of head then into duodenum (minor duodenal papilla)
Arterial supply of pancreas
Common hepatic artery and splenic artery (from coeliac trunk origin)
Superior mesenteric artery
6 specific arteries that supply pancreas
Anterior superior pancreaticoduodenal
Posterior superior pancreticoduodenal
Dorsal pancreatic
Great pancreatic
Anterior inferior pancreaticoduodenal
Posterior inferior pancreaticoduodenal
Venous and lymphatic drainage of pancreas
Always flows back through splenic or SMV into liver through portal vein then IVC
Lymph drains to coeliac nodes and SM nodes
ANS for pancreas
Coeliac and SM plexi
Greater and lesser splanchnic nerves
Vagus nerve
Pain referred to epigastric region
Spleen position
Inferior to ribs 9-11 in left hypochondrium
Splenorenal ligament
To left kidney
Carries splenic vessels and pancreas tail
Spleen vessels
Splenic artery from coeliac axis Splenic vein to portal vein Lymph drains to coeliac nodes ANS: coeliac plexus - vagus and greater splanchnic Pain to epigastric region
2 surfaces of spleen
Diaphragmatic
Visceral
2 poles of spleen
Upper
Lower
3 areas of spleen
Gastric
Colic
Renal
2 splenic ligaments
Spenorenal: splenic vessels, tail of pancreas
Gastrosplenic: short gastric vessels and gastro-omental vessels
Splenic rule of odd numbers
1 x 3 x 5 inches
7 ounces
Found under ribs 9-11
3 main porto-systemic shunts
Bottom 1/3 of oesophagus
Around umbilicus
Anus
Trans-pyloric plane
12 key areas
L1 Midway between suprasternal notch and pubic symphysis 1st part duodenum Pylorus Hila of kidneys Neck of pancreas SMA origin PV origin Fundus of gallbladder Tip of 9th costal cartilage Transverse mesocolon origin Colic flexures Spleen End of spinal cord