Abdomin

Anatomy

The Abdomen
Liver :
It is the largest gland in the body (about 2% of body weight in adult). it occupies the right upper quadrant of the abdomen, below diaphragm.
Surface anatomy of the liver:
The liver has 3 borders. Sup., inf. and right borders (i.e. triangle).
The sup. border starts at the point behind the 5th rib in the right midclavicular line, then passes behind xiphisternal junction in the midline. It ends behind a point just below the apex of the heart.
The inf. border starts behind a point just below the apex of the heart, then it passes behind: the junction of the 7th and 8th left costal cartilages, the midway between xiphoid and umbilicus (in the midline), the tip of right 9th costal cartilage, and lowest point of right costal margin.
The right border is between lowest point of right costal margin and the point behind the 5th rib in the right midclavicular line.
Thus normally the liver is just palpable through the abd. wall.

Surfaces of the liver:

Diaphragmatic surface: is dome shaped and conforms to the concavity of the diaphragm. It is divided into superior, anterior, right and posterior.
Superior surface: is in relation through the diaphragm with the base of the right lung, the pericardium of the heart and with the left lung.
Anterior surface: lies against the diaphragm, the costal margin, the xiphoid process and the abdominal wall.
Right and posterior surfaces: they are related to the diaphragm and the ribs.
Visceral surface: It is directed downward, backward and to the left. It is separated from the diaphragmatic surface by the inferior border which is sharp anteriorly but blunt and rounded posterioly. The inferior border is notched anteriorly by ligamentum teres just to the right of the midline. The visceral surface of the liver is in relation with stomach, duodenum, right colic flexure, right kidney and right suprarenal gland. The visceral surface lodges the gallbladder anteriorly and it is deeply indented by the inferior vena cava posterioly. At the middle (center) of the visceral surface of the liver we have the Porta hepatis of the liver which is the region of entrance of hepatic artery, portal vein as well as autonomic nerve fibers and the exit of hepatic bile duct and lymphatics.
From inferior border anteriorly to the Porta hepatis there is a deep fissure for the ligamentum teres (the obliterated remains of the left umbilical vein).
From Porta hepatis to the inferior border posterioly, there is the deep fissure for ligamentum venosum (which is the ligamentum remains of the ductus venosus in the fetus).


Lobes of the liver:
The Porta hepatis, gallbladder fossa, inferior vena cava fossa and the fissures of ligamentum teres and ligamentum venosum combine to form [H] shaped figure which separates the various lobes of the liver.
** To the left of the fissures for ligaments is the left lobe, to the right of the gallbladder and inferior vena cava fossae we have the right lobe.
Quadrate lobe: between gallbladder fossa and ligamentum teres fissure.
Caudate lobe: between ligamentum venosum fissure and inferior vena cava fossa.
Anatomically Quadrate and Caudate lobes are part of right lobe, while functionally they are part of the left lobe.
** Caudate process: it is a part of caudate lobe that forms a ridge between Porta hepatis and the fossa of inferior vena cava.

Peritoneal reflection of the liver:

Liver is completely peritonized except at the bare area. The bare area is an area that lies on the posterosperior part of the diaphragmatic surface of the liver. It has no peritoneal covering (liver is in direct contact with diaphragm) and it lies between the right triangular ligament and inferior vena cava (or between the anterior and posterior coronary ligaments).
Anterior (superior) and posterior (inferior) coronary ligaments: reflection of peritoneum from liver to diaphragm.
Right and left triangular ligaments: the right and left extremities of ant. coronary lig.
Falciform ligament: (peritoneal fold) extends from the umbilicus (ant. abd.wall) to the liver at the notch for the ligamentum teres. It contains the ligamentum teres.
Gall bladder:
It is a pear shaped organ, measuring 7.5×2.5 cm, it stores and concentrates the bile. It lies in the gall bladder fossa (gall bladder bed) on visceral surface of liver. It is divided into fundus, body, neck and cystic duct.
The fundus makes contact with anterior abdominal wall at the tip of right 9th costal cartilage. It rests on transverse colon.
The body and tapered neck are related to the duodenum. The neck is directed toward porta hepatis and become continuous with the cystic duct.
The cystic duct is 2-4 cm long directed backward downward and to the left to join the common hepatic duct close to porta hepatis forming the common bile duct. Com. bile duct is 8 cm long. it descends in the free margin of lesser omentum to the Rt of proper hepatic artery, ant. to the portal vein. Then com.bile duct passes post. to 1st part of duodenum to the Rt of gastroduod. artery then post. to head of pancreas. It opens in the 2nd part of the duodenum (as mentioned before) at greater duod. papilla.

Arteries of liver and gallbladder:

Proper hepatic arteryRight hepatic arteryCystic Artery
Left hepatic artery
Cystic artery may arise from common hepatic artery, it supplies gallbladder.
Arteries of the common bile duct:
Cystic artery.
Right hepatic artery.
Gastroduodenal artery.
Posterior superior pancreaticoduodenal artery.


Veins of the liver:
Left hepatic vein.
Middle hepatic vein.
Right hepatic vein.
All join the inferior vena cava.
Veins of the gallbladder:
*Gallbladder drained by cystic vein to portal vein directly.
* Veins of gallbladder and bile ducts may drain directly into the liver.

Lymphatics of liver:

Liver produces about 1/2 of all body lymph. The lymphatic vessels pass to porta hepatis lymph nodes then to celiac lymph nodes. A small number of lymphatics pass from the bare area of liver through the diaphragm to the post. mediastinal L.N.
** Lymphatics of the gallbladder and bile ducts pass to cystic nodes (on cystic duct) and nodes in the porta hepatis then to celiac lymph nodes.

Nerves of liver:

Nerve supply of liver is from:
Hepatic plexus: from celiac plexus which gives sympathetic and parasympathetic innervations.
Ant. vagal trunk: gives hepatic branch which will pass directly to the liver.

Gall bladder takes innervations from celiac plexus (sympathetic, parasympathetic), right phrenic nerve (sensory).