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Hi there. I need an answer urgently for a PBL topic. What actually is a hepatic pedicle? And what is the significance of it? Thanks!
Hepatic pedicle
- Thread starter ericdamiansean
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Wrong section, but a 2 second search uncovered this:
Hepatic Pedicle: Variations in Arteries and Bile Ducts.
The arrangement of the vessels and ducts given as normal constitute only 69 cases of the 200 studied (34.5%) by Flint (A). "So frequent are variations that it is impossible to regard any one type as normal; the arrangement found in the 69 cases can only be described as the most usual one."
ACA, Accessory cystic artery; CA, cystic artery; CAA, celiac trunk; CD, cystic duct; GA, gastric artery; GDA, gastroduodenal artery; HA, hepatic artery; LHA, left hepatic artery; PV, portal vein; RHA, right hepatic artery; RHD, right hepatic duct; SA, splenic artery; SMA, superior mesenteric artery; SPDA, superior pancreatoduodenal artery.
Right Hepatic Artery
This artery arose from the common hepatic in 158 cases, and reached the liver by passing behind the common hepatic duct in 136 cases (A), and ih front of the duct in 22 cases (B). In 42 cases the right hepatic artery arose from the superior mesenteric (C), and always passed behind the common duct. In 7 cases there were two right hepatic arteries, one from the hepatic trunk and one from the superior mesenteric artery (D). In 2 cases there were two right hepatic arteries both from the common hepatic, one passed in front of, and the other behind, the common hepatic duct.
In 4 cases, in addition to passing behind the ducts, the common hepatic or the right hepatic artery also passed behind the portal vein (E and W).
Authors' note: The right hepatic artery may also arise from the aorta, right renal, gastric, or inferior mesenteric artery. No such cases were found in Flint's series.
Cystic Artery
The cystic artery arose from the right hepatic artery in 196 of the 200 cases; in 3 cases from the left hepatic (I and Y), and in 1 case from the gastroduodenal artery (H).
In 32 cases it passed in front of ihe common hepatic duct (E and G), and in 168 it arose from the right side of the common hepatic duct (A) or behind it (A'), the former being the more common.
Accessory Cystic Artery
In 31 cases there was an accessory cystic artery and in 169 cases a single cystic. The accessory cystic artery arose from the right hepatic in 16 (D, J, and K), from the left hepatic in 3 (L and Y), from the gastroduodional in 11 (M), and from the superior pancreatoduodenal in 1 case (N) out of the 200.
Left Hepatic Artery (100 cases studied)
In 32 cases there were two left hepatic arteries with one coming from the common hepatic and the other from the gastric, and in 1 case the left lobe of the liver received its arterial supply from the gastric only.
Bile Ducts
According to Flint, the most common point at which union actually occurs is within 1 cm of the upper border of the duodenum (H). In 28 cases there were no supraduodenal common bile ducts at all (T), the union taking place at a point anywhere from behind the upper border of the duodenum to the part embedded in the pancreas, and in 3 cases the only representative of the common duct was the part that lies in the wall of the duodenum (U).
Accessory Bile Ducts
Flint reported 29 examples of accessory right hepatic ducts (F, X, Y, A', and C').
Hepatic Pedicle: Variations in Arteries and Bile Ducts.
The arrangement of the vessels and ducts given as normal constitute only 69 cases of the 200 studied (34.5%) by Flint (A). "So frequent are variations that it is impossible to regard any one type as normal; the arrangement found in the 69 cases can only be described as the most usual one."
ACA, Accessory cystic artery; CA, cystic artery; CAA, celiac trunk; CD, cystic duct; GA, gastric artery; GDA, gastroduodenal artery; HA, hepatic artery; LHA, left hepatic artery; PV, portal vein; RHA, right hepatic artery; RHD, right hepatic duct; SA, splenic artery; SMA, superior mesenteric artery; SPDA, superior pancreatoduodenal artery.
Right Hepatic Artery
This artery arose from the common hepatic in 158 cases, and reached the liver by passing behind the common hepatic duct in 136 cases (A), and ih front of the duct in 22 cases (B). In 42 cases the right hepatic artery arose from the superior mesenteric (C), and always passed behind the common duct. In 7 cases there were two right hepatic arteries, one from the hepatic trunk and one from the superior mesenteric artery (D). In 2 cases there were two right hepatic arteries both from the common hepatic, one passed in front of, and the other behind, the common hepatic duct.
In 4 cases, in addition to passing behind the ducts, the common hepatic or the right hepatic artery also passed behind the portal vein (E and W).
Authors' note: The right hepatic artery may also arise from the aorta, right renal, gastric, or inferior mesenteric artery. No such cases were found in Flint's series.
Cystic Artery
The cystic artery arose from the right hepatic artery in 196 of the 200 cases; in 3 cases from the left hepatic (I and Y), and in 1 case from the gastroduodenal artery (H).
In 32 cases it passed in front of ihe common hepatic duct (E and G), and in 168 it arose from the right side of the common hepatic duct (A) or behind it (A'), the former being the more common.
Accessory Cystic Artery
In 31 cases there was an accessory cystic artery and in 169 cases a single cystic. The accessory cystic artery arose from the right hepatic in 16 (D, J, and K), from the left hepatic in 3 (L and Y), from the gastroduodional in 11 (M), and from the superior pancreatoduodenal in 1 case (N) out of the 200.
Left Hepatic Artery (100 cases studied)
In 32 cases there were two left hepatic arteries with one coming from the common hepatic and the other from the gastric, and in 1 case the left lobe of the liver received its arterial supply from the gastric only.
Bile Ducts
According to Flint, the most common point at which union actually occurs is within 1 cm of the upper border of the duodenum (H). In 28 cases there were no supraduodenal common bile ducts at all (T), the union taking place at a point anywhere from behind the upper border of the duodenum to the part embedded in the pancreas, and in 3 cases the only representative of the common duct was the part that lies in the wall of the duodenum (U).
Accessory Bile Ducts
Flint reported 29 examples of accessory right hepatic ducts (F, X, Y, A', and C').
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right half Surgical anatomy of the liver
Understanding liver anatomy is of importance in liver resection. The liver lies in the abdominal cavity, where it is split into a large right and a small left lobe by the falciform ligament extending from the anterior abdominal wall. The morphology does not correspond to the surgical anatomy of the liver and functionally the liver is divided into a right and left hemi-liver by the principal plane (Rex-Cantlie line). This is a plane passing through the gallbladder bed towards the vena cava and passes through the right axis of the caudate lobe. the middle hepatic vein lies in this plane. Although this was first recognised by Ton That Tung in 1939, it was Couinaud in 1957 who provided the definitive description.
The right hemi-liver is divided into anterior and posterior sections by the course of the right hepatic vein which lies in the inter-sectional plane. This plane lies coronally through the of the liver. The left hemi-liver is divided into lateral and medial sections by the left hepatic vein. Further portal inflow division results in each section in turn being subdivided into two segments with the exception of the left lateral section (one segment only). The divisions of the portal vein are mirrored by divisions of the bile duct and hepatic artery forming a ?portal trinity?, a division of which supplies each segment.
The right portal pedicle is short (less than 1 cm in most) and the vein divides to supply the right anterior section, subdivided into segments V (inferior) and VIII (superior) by portal vein divisions and the right posterior section subdivided into segments VI (inferior) and VII (superior) by portal vein divisions. The left portal pedicle is long. It gives of a caudate branch and thereafter the vein divides to supply a left lateral section and a left medial section. The left medial section is divided into two segments, III and IV, by a further portal vein division. The left lateral section is the one exception to the rule as there is no further major portal vein division. Thus it only has one segment, segment II. The left anterior and posterior sections are separated by the left fissure. The caudate lobe is a distinct anatomical segment and is labeled segment I. It receives branches of the portal trinity from the right and left liver and drains independently into the vena cava.
As each segment of liver has its own supply from the portal trinity, independent of the other segments, these can therefore be resected independently of other segments. In practice, it is easier to remove some segments together. Although the inter-segmental planes are not visible on the surface of the liver, segments can be defined by occluding the inflow to that segment thus rendering the segment ischaemic.
The major hepatic veins do not correspond to the segmental division of the liver. The three named superior hepatic veins (right, middle, and left) lie in the 3 main fissures and between the 4 hepatic sections. The right vein lies in the right fissure between the right anterior section and posterior section, the middle vein in the principal plane between the right and left hemi-liver, and the left vein between the left anterior and posterior section. Each vein drains the section on either side of it. The right vein drains into the vena cava independently, but the middle and left veins usually join and drain into the vena cava as a single vein. There are usually a few small veins draining into the vena cava from behind the liver. Occasionally there can be 2 or 3 inferior right hepatic veins of moderate size and these can provide significant drainage. If these are not recognized and torn during hepatic resection bleeding may be profuse.
It has been recognised that Glisson?s capsule extends as a condensation of fascia around the bilio-vascular branches of the portal trinity (Glissonian sheath?s). Couinaud and more recently Launois and Jamieson have noted that the fascia continues within the liver parenchyma up to the segmental divisions. The surgical implication is that if the supply to an individual segment is approached from within the liver, mass ligation of a sheath will devascularise the segment. This is simplified even further by the use of a stapler.
Understanding liver anatomy is of importance in liver resection. The liver lies in the abdominal cavity, where it is split into a large right and a small left lobe by the falciform ligament extending from the anterior abdominal wall. The morphology does not correspond to the surgical anatomy of the liver and functionally the liver is divided into a right and left hemi-liver by the principal plane (Rex-Cantlie line). This is a plane passing through the gallbladder bed towards the vena cava and passes through the right axis of the caudate lobe. the middle hepatic vein lies in this plane. Although this was first recognised by Ton That Tung in 1939, it was Couinaud in 1957 who provided the definitive description.
The right hemi-liver is divided into anterior and posterior sections by the course of the right hepatic vein which lies in the inter-sectional plane. This plane lies coronally through the of the liver. The left hemi-liver is divided into lateral and medial sections by the left hepatic vein. Further portal inflow division results in each section in turn being subdivided into two segments with the exception of the left lateral section (one segment only). The divisions of the portal vein are mirrored by divisions of the bile duct and hepatic artery forming a ?portal trinity?, a division of which supplies each segment.
The right portal pedicle is short (less than 1 cm in most) and the vein divides to supply the right anterior section, subdivided into segments V (inferior) and VIII (superior) by portal vein divisions and the right posterior section subdivided into segments VI (inferior) and VII (superior) by portal vein divisions. The left portal pedicle is long. It gives of a caudate branch and thereafter the vein divides to supply a left lateral section and a left medial section. The left medial section is divided into two segments, III and IV, by a further portal vein division. The left lateral section is the one exception to the rule as there is no further major portal vein division. Thus it only has one segment, segment II. The left anterior and posterior sections are separated by the left fissure. The caudate lobe is a distinct anatomical segment and is labeled segment I. It receives branches of the portal trinity from the right and left liver and drains independently into the vena cava.
As each segment of liver has its own supply from the portal trinity, independent of the other segments, these can therefore be resected independently of other segments. In practice, it is easier to remove some segments together. Although the inter-segmental planes are not visible on the surface of the liver, segments can be defined by occluding the inflow to that segment thus rendering the segment ischaemic.
The major hepatic veins do not correspond to the segmental division of the liver. The three named superior hepatic veins (right, middle, and left) lie in the 3 main fissures and between the 4 hepatic sections. The right vein lies in the right fissure between the right anterior section and posterior section, the middle vein in the principal plane between the right and left hemi-liver, and the left vein between the left anterior and posterior section. Each vein drains the section on either side of it. The right vein drains into the vena cava independently, but the middle and left veins usually join and drain into the vena cava as a single vein. There are usually a few small veins draining into the vena cava from behind the liver. Occasionally there can be 2 or 3 inferior right hepatic veins of moderate size and these can provide significant drainage. If these are not recognized and torn during hepatic resection bleeding may be profuse.
It has been recognised that Glisson?s capsule extends as a condensation of fascia around the bilio-vascular branches of the portal trinity (Glissonian sheath?s). Couinaud and more recently Launois and Jamieson have noted that the fascia continues within the liver parenchyma up to the segmental divisions. The surgical implication is that if the supply to an individual segment is approached from within the liver, mass ligation of a sheath will devascularise the segment. This is simplified even further by the use of a stapler.
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I'll just give the points up on this topic on the MCAT...
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