L6. Anatomy of the abdominal viscera: accessory organs

Question 1

What two features must be present in order to call a surface a visceral surface in the abdominal cavity?

Answer 1

It must bear the imprint of adjacent structures and it must have the hilum

Question 2

What is the liver? What are the surfaces of the liver and what demarcates them?

Why is this border clinically relevant?

Answer 2

Liver is a solid viscous with 2 surfaces (diaphragmatic and visceral) - demarcated by a sharp inferior border

Important clinically because enlarged liver is palpable here under the right costal margin.

Question 3

Where is the liver located?

Answer 3

Right upper quadrant, related to right dome of diaphragm (the diaphragmatic surface is thus smooth

Question 4

What structure projects past the inferior edge of the liver?

Answer 4

The tip of the gall bladder

Question 5

Describe the lobar structure of the liver

Answer 5

Divided into 2 unequal lobes (right and left) by the falciform ligament.

Question 6

What is the falciform ligament?

Answer 6

It is a peritoneal reflexion (smooth and shiny, serous membrane) and is a double layer that connects the diaphragmatic surface to the anterior abdominal wall.

There is a free interior edge to the ligament at the level of the umbilicus and it contains the ligamentum teres of the liver (fibrous cord that represents the obliterated umbilical vein which once carried blood from the placenta to foetus).

Question 7

The surface of the liver is covered by peritoneum. Describe the superior part of the liver (from the ligamentum teres and falciform ligament)

Answer 7

The peritoneum reflects off the superior aspect of the liver and onto the under surface of the diaphragm - coronary ligament (reflexion of peritoneum).

Following the ligaments laterally, they become the right and left triangular ligaments.

The whole top of the liver is covered by peritoneum except one small bare area.

Question 8

Describe the visceral surface of the liver

Answer 8

Visceral surface relates to the abdominal contents: bares impressions of the structures it relates to and also has the hilum (root) of the liver called the PORTA HEPATIS. Gastric impression on the left lobe seen.

It has a H shaped fissure

Question 9

What lies in the important parts of the H shaped fissure on the visceral surface of the liver?

Answer 9

Cross piece being the porta hepatis (neurovascular and ducts entering and exiting).

Embedded in the grooves the right hand side is the gall bladder at the front and the IVC embedded into the groove behind.

On the left hand side on the H there are 2 fibrous structures grooving the liver: the ligamentum teres and falciform ligament and the ligamentum venosum (superiorly)

Question 10

What is the ligamentum venosum?

Answer 10

Lies between the left lobe and the caudate lobe

An embryological remnant communicating with the left portal vein - it was once bringing oxygenated blood from umbilicus to the liver.

A shunt directly from left portal vein into the left hepatic vein and IVC - ductus venosum and is now the ligumentum venosum.

Question 11

What are the four lobes of the liver seen from the visceral surface?

Answer 11

Left lobe
Caudate Lobe (between the IVC and the ligamentum venosum)
Quadrate Lobe (between the gall bladder and the falciform ligament)
Right Lobe

Question 12

What are the vessels running through the porta hepatis? What is their arrangement?

Answer 12

Portal vein behind, hepatic artery (to the left) and hepatic duct (to the right) in front.

Nerves and lymphatics scattered.

Question 13

What is the caudate process?

Answer 13

Part of the caudate lobe sitting under the IVC that connects the caudate lobe to the right lobe

Question 14

Describe the relationship between the lesser omentum of the stomach and the liver

Answer 14

There is peritoneal attachment between the lesser omentum and the liver (to the visceral aspect - porta hepatis).

Question 15

What is important about the free edge of the lesser omentum? How is it formed?

Answer 15

The lesser omentum stops on the right side because the duodenum becomes retroperitoneal (dives back) and there is a resultant free edge of the lesser omentum.

The portal triad from the posterior wall to the porta hepatis by running in this free edge of the lesser omentum.

Question 16

Describe the vascular input of the liver

Answer 16

The hepatic artery divides into right and left terminal branches for the two halves of the liver and enters the hilum.

The liver also gets blood from the portal vein, ascending and divides into right and left venous structure to enter the hilum.

Question 17

Describe the venous drainage of the liver

Answer 17

Drained by hepatic veins (usually 3 in number) drains directly into the IVC (embedded into the visceral surface). Never see the veins outside the liver (can see the openings)

There is no venous drainage out of the porta hepatis

Question 18

What is carried out of the duct coming out of the porta hepatis? Where does it go?

Answer 18

Bile is produced and secreted by liver cells and empties into ducts which get larger eventually forming the right and left hepatic ducts which join and form the common hepatic duct leaving the porta hepatis.

The gall bladder stores and concentrates the bile

Question 19

Describe the path of the common hepatic duct down towards the duodenum

Answer 19

The duct descends in the free edge of the lesser omentum.

It transverses behind the first part of the duodenum and into the groove of formed by the pancreatic head

It passes behind the second part of the duodenum until they find the middle part of the vertical duodenum and opens into the wall

Question 20

Describe the anatomy of the gall bladder

Answer 20

Pear shaped sac and divided into a FUNDUS (beyond inferior edge), BODY and NECK, which becomes continuous with the duct of the gall bladder: CYSTIC DUCT

Question 21

Describe how the cystic duct of the gall bladder and the hepatic duct of the liver meet and then the pancreatic duct

Answer 21

The cystic duct lies over the front of the first part of the duodenum. And it eventually transverses to join the hepatic duct at which point it becomes the COMMON BILE DUCT.

The common bile duct eventually meets the major pancreatic duct and they form the main duct that empties into the Major papilla in the wall of the second part of the duodenum.

Question 22

What surrounds the terminal portions of the hepatic and pancreatic ducts? What is important about this?

Answer 22

Smooth muscle surrounds the common opening where the 2 ducts have joined as well as the distal portion of the duct.

It forms a sphincter is that is normally closed (when digestion is not taking place) so that enzymes and bile don’t enter the system.

Thus bile backs up in the bile duct (accumulates) and then stored and concentrated in the gall bladder until is required.

Question 23

Describe the location, shape and function of the pancreas

Answer 23

Pancreas is located centrally with its head surrounded by the duodenum and its tail projecting into the hilum of the spleen.

It is classically described as having a comma shape

Function: Important endocrine (eg. insulin) and exocrine functions (enzymes for digestion).

Question 24

Describe the anatomy of the pancreas

Answer 24

Moving from Right to Left:

HEAD: in C shaped curve of the duodenum, and contains the uncinate process
NECK: runs over the top of the superior mesenteric vessels
BODY: is above the duodenojejunal flexure (DJF)
TAIL: runs across to the left hand side and is directly at the hilum of the spleen

Question 25

What is the uncinate process of the head of the pancreas?

Answer 25

It is a wedge shaped projection off the head and lies posterior to the superior mesenteric vessels (which cross over the duodenum and this process).
It is also related to the third part of the duodenum

Question 26

Describe the pancreatic duct(s)

Answer 26

It transverses from the tail of the pancreas collecting pancreatic enzymes, gets larger as it transverses and joins the common bile duct and enters the main duodenum papilla.

The second, smaller pancreatic duct drains the distal portion of the head and uncinate process, crossing the major duct and enters the duodenum. This duct has no relationship or interaction with the bile duct

Question 27

What is the spleen?

Answer 27

Oval shaped mass of lymphoid tissue, about the size of a clenched fist (variable) - they get smaller in the elderly population.

The whole thing is incredibly vascular: damage = bleeding

Question 28

Where is the notched border of the spleen and what does it represent?

Answer 28

Notched border of the spleen - the border that divides the smooth diaphragmatic surface from the visceral surface (which has hilum and imprints)

It represents evolutionary processes (non-complex species have multiple spleens, stipulated humans once had this arrangement)

Question 29

Is there a duct running through the hilum of the spleen?

Answer 29

There is no duct to the spleen, the hilum contains only neurovascular and lymphatic structures

Question 30

How is the spleen related to the rib cage? What is the implication of this?

Answer 30

The spleen relates to the diaphragm, beneath the left dome directly related to ribs 9,10 and 11. The axis relates to the shaft of the 10th rib.

Fractures of these ribs risk tearing of the spleen - very dangerous