SURGICAL ANATOMY AND PHYSIOLOGY

SURGICAL ANATOMY AND PHYSIOLOGY
The gall bladder lies on the underside of the liver in the main liver scissura at the junction of the right and left lobes of the liver. The relationship of the gall bladder to the liver varies between being embedded within the liver substance to suspended by a mesentery. It is a pear-shaped structure, 7.5–12 cm long, with a normal capac- ity of about 35–50 ml. The anatomical divisions are a fundus, a body and a neck that terminates in a narrow infundibulum. The muscle fibres in the wall of the gall bladder are arranged in a criss- cross manner, being particularly well developed in its neck. The mucous membrane contains indentations of the mucosa that sink into the muscle coat; these are the crypts of Luschka.

The cystic duct is about 3 cm in length but variable. Its lumen is usually 1–3 mm in diameter. The mucosa of the cystic duct is arranged in spiral folds known as the valves of Heister. Its wall is surrounded by a sphincteric structure called the sphincter of Lütkens. While the cystic duct joins the common hepatic duct in its supraduodenal segment in 80% of cases, it may extend down into the retroduodenal or even retropancreatic part of the bile duct before joining. Occasionally, the cystic duct may join the right hepatic duct or even a right hepatic sectorial duct.