Liver anatomy

liver basic anatomy

1. Dr.P.A.Sathagurunath

2. Largest organ Located in right upper quadrant, extends into epigastrium and left upper quadrant ,abutting the splenic contour. Weight : Males – 1.4-1.7 kgs and Female – 1.2 -1.5 kgs .

3. E ight functionally independent segments. Each segment has its own vascular inflow, outflow and biliary drainage. In the centre of each segment there is a branch of the portal vein, hepatic artery and bile duct. In the periphery of each segment there is vascular outflow through the hepatic veins. Couinad classification

4. Right hepatic vein divides the right lobe into anterior and posterior segments. Middle hepatic vein divides the liver into right and left lobes (or right and left hemi liver ). This plane runs from the inferior vena cava to the gallbladder fossa . Left hepatic vein divides the left lobe into a medial and lateral part.

5. Couinaud divided the liver into a functional left and right liver by a main portal scissurae containing the middle hepatic vein. This is known as Cantlie's line . Cantlie's line runs from the middle of the gallbladder fossa anteriorly to the inferior vena cava posteriorly .

6. Portal vein divides the liver into upper and lower segments. The left and right portal veins branch superiorly and inferiorly to project into the center of each segment.

7. Because of this division into self-contained units, each segment can be resected without damaging those remaining. For the liver to remain viable, resections must proceed along the vessels that define the peripheries of these segments. This means, that resection-lines parallel the hepatic veins, The centrally located portal veins, bile ducts, and hepatic arteries are preserved.

8. PORTAL TRIAD

9. There are eight liver segments. Segment 4 is divided into segment 4a and 4b according to Bismuth. The numbering of the segments is in a clockwise manner Segment 1 (caudate lobe) is located posteriorly . It is not visible on a frontal view.

10. the medial part of the left lobe is separated from the lateral part by the falciform ligament. However it actually is the left hepatic vein, that separates the medial part (segment 4) from the lateral part (segments 2 and 3). The left hepatic vein is located slightly to the left of the falciform ligament. Left lobe

11. Image at the level of the superior liver segments. This figure is a transverse image through the superior liver segments, that are divided by the right and middle hepatic veins and the falciform ligament.

12. Image at the level of the left portal vein This is a transverse image at the level of the left portal vein. At this level the left portal vein divides the left lobe into the superior segments (II and IVa ) and the inferior segments (III and IVb ). The left portal vein is at a higher level than the right portal vein.

13. Image at the level of the right portal vein. Image at the level of the right portal vein. This image is at the level of the right portal vein. At this level the right portal vein divides the right lobe of the liver into superior segments (VII and VIII) and the inferior segments (V and VI). The level of the right portal vein is inferior to the level of the left portal vein.

14. Image at the level of the splenic vein At the level of the splenic vein, which is below the level of the right portal vein, only the inferior segments are visible.