| Lobes of liver | |
|---|---|
 Theliver is divided into four lobes. This image shows the large right lobe and a smaller left lobe separated by thefalciform ligament. | |
 1:Right lobe of liver 2:Left lobe of liver 3:Quadrate lobe of liver 4:Round ligament of liver 5:Falciform ligament 6:Caudate lobe of liver 7:Inferior vena cava 8:Common bile duct 9:Hepatic artery 10:Portal vein 11:Cystic duct 12:Common hepatic duct 13:Gallbladder | |
| Details | |
| Identifiers | |
| Latin | lobus hepatis |
| Anatomical terminology | |
Inhuman anatomy, theliver is dividedgrossly into four parts orlobes: theright lobe, theleft lobe, thecaudate lobe, and thequadrate lobe. Seen from the front – thediaphragmatic surface – the liver is divided into two lobes: the right lobe and the left lobe. Viewed from the underside – thevisceral surface – the other two smaller lobes, the caudate lobe and the quadrate lobe, are also visible.[1] The two smaller lobes, the caudate lobe and the quadrate lobe, are known as superficial or accessory lobes, and both are located on the underside of the right lobe.[2]
Thefalciform ligament, visible on the front of the liver, makes a superficial division of the right and left lobes of the liver. From the underside, the two additional lobes are located on the right lobe.[2] A line can be imagined running from the left of thevena cava and all the way forward to divide the liver andgallbladder into two halves.[3] This line is calledCantlie's line and is used to mark the division between the two lobes.[4]
Other anatomical landmarks exist, such as theligamentum venosum and theround ligament of the liver (ligamentum teres), which further divide the left side of the liver in two sections. An important anatomical landmark, theporta hepatis, also known as thetransverse fissure of the liver, divides this left portion into four segments, which can be numbered inRoman numerals starting at the caudate lobe as I in an anticlockwise manner. From thisparietal view, seven segments can be seen, because the eighth segment is only visible in the visceral view.[5]
The lobes of the liver are further divided into eightliver segments in theCouinaud system. These are also known as hepatic segments that aresurgically resectable.[2]
The ''left lobe'' is smaller and more flattened than the right. It is situated in theepigastric, and lefthypochondriacregions of the abdomen. Its upper surface is slightly convex and is moulded on to the diaphragm; its under surface presents the gastric impression andomental tuberosity.
Theright lobe is six times the size of the left lobe. It occupies theright hypochondrium, on its posterior surface by theligamentum venosum for the cranial (upper) half and by the ligamentum teres hepatis (round ligament of liver) for the caudal (under) half. Theligamentum teres hepatis turns around the inferior margin of the liver to come out ventral in thefalciform ligament.
The right lobe is functionally separated from the left lobe by the middle hepatic vein. From a functional perspective (one that takes the arterial, portal venous, and systemic venous anatomy into account) the falciform ligament separates the medial and lateral segments of the left hepatic lobe.[6]
The right lobe is of a somewhat quadrilateral form. Its under and posterior surfaces being marked by three fossæ: the fossa for theportal vein, the fossa for thegall-bladder and the fossae for theinferior vena cava. These separate the right lobe into two smaller lobes on its left posterior part: the quadrate lobe and the caudate lobe.
Thequadrate lobe is an area of theliver situated on the undersurface of the medial segment left lobe (Couinaud segment IVb), bounded in front by the anterior margin of the liver, behind by theporta hepatis, on the right by the fossa for thegall-bladder, and on the left by the fossa for theumbilical vein.
It is oblong in shape, its antero-posterior diameter being greater than its transverse.
Thecaudate lobe (posterior hepatic segment I) is situated upon the posterosuperior surface of the liver on the right lobe of the liver, opposite the tenth and elevenththoracic vertebrae.
The caudate lobe of the liver is bounded below by theporta hepatis, on the right by the fossa for theinferior vena cava, and on the left by the fossa for theductus venosus and the physiological division of the liver, called theligamentum venosum. It looks backward, being nearly vertical in position; it is longer from above downward than from side to side, and is somewhat concave in the transverse direction. It is situated behind theporta, and separates the fossa for thegall-bladder from the commencement of the fossa for theinferior vena cava.See Adriaan van den Spiegel 1578-1625 Spiegel's lobe.
Budd–Chiari syndrome, caused by occlusion of hepatic venous outflow, can lead to hypertrophy of the caudate lobe due to its own caval anastomosis that allows for continued function of this lobe of the liver.
The caudate lobe is named after the tail-shaped hepatic tissue (cauda; Latin, "tail") papillary process of the liver, which arise from its left side. It also has a caudate process (that is not tail-like shaped) arising from its right side, which provides surface continuity between the caudate lobe and the visceral surface of the anatomical right lobe of the liver.[2] The caudate process is a small elevation of the hepatic substance extending obliquely and laterally, from the lower extremity of the caudate lobe to the undersurface of the right lobe.
The caudate lobe has a complex blood supply system. It derives its arterial supply from the caudate arteries, which arise from the right, left, and middle hepatic arteries that are connected to each other.[7] Besides, the caudate lobe also derives its supply from the right and left branches of the portal vein. Its venous drainage is through short hepatic veins that drain directly into the inferior vena cava (IVC) due to its proximity to the IVC.[8]
This article incorporates text in thepublic domain from the 20th edition ofGray's Anatomy(1918)
