APC3

Question 1

Where is the liver positioned?

Answer 1

Occupies most of right hypochondrium, extends through epigastrium –> left hypochondrium

Most under ribs and costal cartilages
Contact with inferior surface of diaphragm

Question 2

How does the liver develop? How is its position maintained

Answer 2

Between the two layers of ventral mesogastrium of the embryo

Although liver connected to adjacent structures by peritoneum - not its main support

Maintained by attachment of HEPATIC VEINS which drain blood to IVC posteriorly

In many instances inferior vena cava embedded in liver tissue, other times hepatic veins will run short extra-hepatic course

Question 3

Surface anatomy of liver?

Answer 3

Markings relatively constant in healthy individuals, but can change considerably in disease states

1) Right upper limit: upper margin right 5th rib, mid-clav line
2) Midpoint superior surface: junction of xiphoid & body of sternum
3) Lower margin of left 5th rib, mid-clav line
4) Right lower: close to lowest point of right costal margin
5) : between upper and lower right limits (1+4)

Question 4

What is the H shape of the liver?

Answer 4

5 important structures of visceral surface of liver

1) Gall bladder anteriorly, IVC posteriorly
2) Hilum of liver (vessels enter, ducts leave) - porta hepatic

3) Falciform ligament anteriorly, attachment of lesser omentum posteriorly
(double layers of peritoneum, remnants of ventral mesograstrium [caudal foregut –> AAW] and associated embryological remnants)

Question 5

What is the liver invested by?

Answer 5

Peritoneum derived from ventral mesogastrium

Reflected onto adjacent structures at certain points

Question 6

Describe the lines of peritoneal reflection on the liver

Answer 6

Starting at inferior surface - ANTERIOR LIMB of LEFT CORONARY LIGAMENT -> peritoneum would be reflected off the liver and onto undersurface of diaphragm in continuity with parietal peritoneum

Line moves towards ANTERIOR surface where becomes one layer of the FALCIFORM LIGAMENT which projects onto AAW as far as umbilicus

Right layer of falciform ligament continues with UPPER/ANTERIOR layer of CORONARY LIGAMENT - continues as UPPER LIMB of RIGHT TRIANGULAR ligament

Lower limb of RIGHT TRIANGULAR ligament continues obliquely as the LOWER/POSTERIOR layer of the CORONARY ligament (space enclosed by two ligaments = BARE AREA - no peritoneum)

Right triangular and coronary ligaments reflected onto DIAPHRAGM and PAW

Peritoneal line of reflexion anterior to IVC –> posterior layer of ROOT of LESSER OMENTUM -> continuous with porta hepatis (partly enclosed by peritoneum which is continuous with POSTERIOR layer of ROOT of lesser omentum)

Posterior layer continuous with POSTERIOR LIMB of LEFT TRIANGULAR LIGAMENT

Question 7

Reminder: learn liver histology

Answer 7

!

Question 8

What is the ductus venosus?

Answer 8

Connects porta hepatis to IVC (oxygenated blood from umbilical vein –> hepatic portal vein)

Ductus venous allows oxygenated blood to bypass hepatic circulation and go to systemic circulation rapidly by going straight to IVC

Soon after birth umbilical vein and ductus venosus undergo fibrosis and close

Question 9

What is ligamentum teres?

Answer 9

Lies within free edge of falciform ligament, connecting porta hepatis superiorly with umbilicus inferiorly

Question 10

What is the ligamentum venosum?

Answer 10

Lies between hepatic portal vein at porta hepatis and inferior vena cava - enclosed within the root of the lesser omentum

Question 11

How can the liver be anatomically divided?

Answer 11

Right and left lobes marked by sagittal plane through falciform ligament and fissures for ligamentum teres and ligamentum venosum

Right lobe - two smaller parts: caudate and quadrate lobes

Caudate: between IVC and fissure for ligamentum venous

Quadrate: between gall bladder bed and ligamentem teres

Question 12

What are the subphrenic spaces?

Answer 12

ANTERIOR subphrenic recess

Formed by peritoneal attachment of liver to diaphragm

Right and left spaces either side of falciform ligament (where peritoneum reflected off posterior liver onto diaphragm)

Question 13

What is the hepatorenal pouch?

Answer 13

The right posterior subphrenic space

Superior to retroperitoneal kidney - posterior to right anatomical lobe of liver where peritoneum is being reflected onto diaphragm

Important clinically as a site of fluid collection (so is the rectovesical/rectouterine pouch)

Question 14

Which areas of abdominopelvic cavity will leakage gravitate (GI tract rupture) in supine and seated position? Where would pain be felt if leakage was irritant?

Answer 14

Supine: Hepatorenal pouch (right posterior subphrenic space) and rectovesical/rectouterine pouch

Seated: ?

Pain: ?

Question 15

What organs is the liver related to?

Answer 15

In life, posture and movements of respiration may affect relationships of liver

Visceral surface of right lobe of the liver is related to the right suprarenal gland, right kidney and transverse colon

Visceral surface of left lobe in contact with stomach and oesophagus

Question 16

What is the common hepatic artery?

Answer 16

Branch of celiac, follows retroperitoneal course to the right, towards superior (first) part of duodenum

At this point, splits to become hepatic artery proper and gastroduodenal artery

Question 17

What is the hepatic artery proper?

Answer 17

(from common hepatic)

Enters mesentery of initial part of duodenum, then curves upwards between the 2 layers of the free edge of the lesser omentum with the BILE DUCT and HEPATIC PORTAL VEIN to liver

Gives off right gastric artery

On reach porta hepatis - divides into right and left branches supplying physiogical/functional lobes

Hepatic artery delivers about 20% of blood reaching the liver

Question 18

What is the gastroduodenal artery?

Answer 18

(from hepatic artery)

Passes inferiorly behind superior/first part of duodenum along with the bile duct and the hepatic portal vein

Arising from gastroduodenal artery –> RIGHT GASTROEPIPLOIC and SUPERIOR PANCREATICODUODENAL

Question 19

What are hepatic veins and how are they formed? (venous drainage of liver)

Answer 19

Blood in SINUSOIDS drains to CENTRAL VEINS of liver lobules –> unit to larger veins –> eventually MAIN HEPATIC veins which drain all blood from liver into IVC

Usually 3 - often completely embedded in liver tissue along with IVC

Devoid of valves

Pattern of venous drainage not closely related to physiological lobes of the liver - (those lobes are defined by branches of the hepatic artery / hepatic portal vein )

Question 20

What is the hepatic portal vein?

Answer 20

Drains venous blood from GI tract, between lower part of oesophagus and upper part of anal canal - and associated organs

Contains products of digestion and ~80% of blood brought to liver –> neither HPV or its tributaries contain vein

Formed behind NECK of pancreas by union of SUPERIOR MESENTERIC vein and SPLENIC vein (splenic receives inferior mesenteric initially - IM drains all hindgut structures to splenic vein and SM drains midgut/caecum)

Travels behind 1st part duodenum and here enters free margin of lesser omentum to eventually reach porta hepatis where divides into right and left branches (supplies right and left physiological lobes)

Question 21

Venous drainage of oesophagus when considering portal hypertension?

Answer 21

In normal conditions: anastomoses closed, but where obstruction of hepatic portal vein e.g. tumours or cirrhosis - communications may be opened up –> varicosities oesophageal varices

Question 22

What are porto-systemic anastomoses?

Answer 22

Sites within GI tract where venous blood from viscera drains to systemic circulation (back to heart) as well as to the portal system:

Lower end of oesophagus: tributaries of left gastric vein (portal) connect with oesophageal tributaries of the azygos or accessory hemiazygos veins (systemic)

In normal conditions: anastomoses closed, but where obstruction of hepatic portal vein e.g. tumours or cirrhosis - communications may be opened up –> varicosities (oesophageal varices)

Also found at wall of anal canal, umbilicus, & sites where viscera are in contact with the abdominal wall, such as retroperitoneal areas of colon and the bare area of the liver

Question 23

What is the hepatic artery related to?

Answer 23

Peritoneum of PAW, duodenum and lesser omentum

Question 24

What is the nerve supply of the liver?

Answer 24

Most pass via porta hepatis, though some fibres pass into the substance of the liver via its peritoneal attachments

SYMPATHETIC nerve fibres supplying from CELIAC GANGLIA enter porta hepatis along the walls of the hepatic ARTERY - principally concerned with vasomotor activity of the branches of the hepatic artery within the liver parenchyma - afferent PAIN impulses may also travel with sympathetic nerves

PARASYMPATHETIC derived from ANTERIOR and POSTERIOR VAGAL TRUNKS - ANTERIOR trunk carries fibres from both vagus nerves and passes to PORTA HEPATIS between two layers of lesser omentum
(function not clear)

Question 25

What is the spleen?

Answer 25

Firm, vascular organ, reddish, about a closed fist

Outer surface convex, inner (visceral) surface concave
Usually notched on anterior surface making it easy to distinguish

Visceral surface has the hilum, where vessels and lymph enter/leave

Question 26

Where is the spleen positioned?

Answer 26

Left hypochondrium at level of posterior parts of 9-11th RIBS

In normal adult, does not extend further forwards than MIDAXILLARY line (lower pole does not usually project anterior to midaxillary line)

Can become enlarged - sometimes to huge proportions and then can be felt below the left costal margin - notch would enable certainty that large spleen is being palpated

Question 27

What is the spleen related to?

Answer 27

Left half of DIAPHRAGM: separating convex surface of spleen from costodiaphragmatic recess of pleural cavity and the 9th-11th ribs

On deep inspiration: left lung will also be in close relationship to spleen

Visceral surface: impressions made by adjacent viscera: STOMACH (close to fundus), KIDNEY, COLON & PANCREAS

Extending right, from hilum of spleen, posterior to stomach = part of LESER SAC

Question 28

What is the peritoneal covering of the spleen?

Answer 28

Develops within dorsal mesogastrium of embryo - provides covering of visceral peritoneum which lies outside connective tissue capsule of spleen

Suspended by two double layers of peritoneum between the PAW and the GREATER CURVATURE of the stomach
(these double layers = LIENORENAL and GASTROSPLENIC ligaments)

Double layer also passes LEFT COLIC FLEXURE –> DIAPHRAGM opposite the 10th and 11th ribs –> PHRENOCOLIC ligament (in contact with the inferolateral part of the spleen & assists in maintaining its position)

Question 29

What is the phrenocolic ligament?

Answer 29

Double layer of peritoneum passes from LEFT COLIC FLEXURE to DIAPHRAGM opposite the 10th and 11th ribs –> PHRENOCOLIC ligament (in contact with the inferolateral part of the spleen and assists in maintaining it in position)

Question 30

What is the lienorenal ligament?

Answer 30

Encloses splenic artery and vein and tail of pancreas

Both lienorenal and gastrosplenic provide routes by which blood vessels pass from abdominal aorta on PAW –> spleen and stomach

Question 31

What is the gastrosplenic ligament?

Answer 31

Encloses the SHORT GASTRIC and LEFT GASTROEPIPLOIC vessels - branches of the splenic artery which supply the stomach

Greater omentum has continuity with gastrosplenic ligament (cut through ligament and get to lesser sac)

Question 32

What is the splenic artery?

Answer 32

Branch of CELIAC artery which runs characteristically TORTUOUS course along superior margin of the PANCREAS

Having passed through the LIENORENAL ligament the artery divides into several branches which enter the hilum of the spleen:

Supplies spleen and pancreas and give rise to SHORT GASTRIC and LEFT GASTROEPIPLOIC arteries near the HILUM of the spleen

Question 33

What is the splenic vein?

Answer 33

Several veins draining spleen unite near HILUM to form splenic vein - passes across PAW, behind BODY of pancreas and joins SUPERIOR MESENTERIC –> forms the HEPATIC PORTAL VEIN, behind the NECK of the pancreas

INFERIOR MESENTERIC VEIN ascends on PAW to left of corresponding artery and joins SPLENIC vein behind PANCREAS

Question 34

What is the lymphatic drainage of the spleen?

Answer 34

Several nodes at HILUM and efferent vessels from these drain to CELIAC group

Question 35

What is a portal venogram?

Answer 35

Radio-opaque medium injected through skin into spleen

Needle passes through: skin, SCT, intercostal space (external, internal and innermost muscles), costal pleura, pleural cavity, diaphragmatic pleura, diaphragm, peritoneum (parietal), visceral peritoneum, spleen

Question 36

CT scan

Answer 36

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Question 37

Liver cirrhosis - why is there blood in vomit and stool?

Answer 37

Bleeding in varicose veins of oesophagus and and rectal veins (wall of anal canal has portosystemic anatomises)

Question 38

Liver cirrhosis - why is the spleen enlarged?

Answer 38

Caused by portal hypertension

Splenic vein drains into portal vein

Question 39

How would cirrhotic liver feel different?

Answer 39

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Question 40

How do ascites form? (cirrhosis)

Answer 40

If portal hypertension has occurred, increased hydrostatic pressure leads to exudate in peritoneal cavity (ascites) and reduced plasma volume (RAAS activation - retention of salt/water - worsening ascites)

Without the portal hypertension, liver failure reduces plasma protein concentration, which reduces oncotic pressure –> exudate in peritoneal cavity (ascites)