The Abdomen and Pelvis 2

The gastrointestinal adnexae: liver, gall bladder

and its ducts, pancreas and spleen

The liver• This is the largest organ in the body. It is related by its domed upper surface to

the diaphragm, which separates it from the pleura, lungs, pericardium and heart. Its postero-inferior (or visceral) surface overlaps the abdominal oesophagus, the stomach and the duodenum, the hepatic flexure of the colon and the right kidney and suprarenal, besides carrying the gall bladder.

• The liver is divided into a larger right and small left lobe, separated superiorly by the falciform ligament and postero-inferiorly by an ‘H’- shaped arrangement of fossae anteriorly and to the right – the fossa for the gall bladder; • posteriorly and to the right – the groove in which the inferior vena cava lies embedded; • anteriorly and to the left – the fissure containing the ligamentum teres; • posteriorly and to the left – the fissure for the ligamentum venosum.

• The cross-bar of the ‘H’ is the porta hepatis. Two subsidiary lobes are marked out on the visceral aspect of the liver between the limbs of this ‘H’ – the quadrate lobe in front and the caudate lobe behind.

• The ligamentum teres is the obliterated remains of the left umbilical vein which, in utero, brings blood from the placenta back into the fetus. The ligamentum venosum is the fibrous remnant of the fetal ductus venosus which shunts oxygenated blood from this left umbilical vein to the inferior vena cava, short-circuiting the liver. It is easy enough to realize, then, that the grooves for the ligamentum teres, ligamentum venosum and inferior vena cava, representing as they do the pathway of a fetal venous trunk, are continuous in the adult. See also ‘The fetal circulation

• Lying in the porta hepatis (which is 2 in (5 cm) long) are:1 the common hepatic duct – anteriorly; • 2 the hepatic artery – in the middle;3 the portal vein – posteriorly.

The gall bladderThe gall bladder normally holds approximately 50 ml of bile and acts as a bile concentrator and reservoir. It lies in a fossa separating the right and quadrate lobes of the liver and is related inferiorly to the duodenum and transverse colon. (An inflamed gall bladder may occasionally ulcerate into either of these structures.)

• For descriptive purposes, the organ is divided into the fundus, body and neck, the last opening into the cystic duct. In dilated and pathological gall. bladders there is frequently a pouch present on the ventral aspect just proximal to the neck termed Hartmann’s pouch in which gallstones may become lodged.

CLINICAL FEATURES

• Errors in gall bladder surgery• Haemorrhage during cholecystectomy• Gangrene of the gall bladder• Stones in the common duct

The pancreas• The pancreas lies retroperitoneally in roughly the transpyloric plane. For

descriptive purposes it is divided into the head, neck, body and tail.

•RelationsThe head lies in the C-curve of the duodenum and sends out the uncinateprocess, which hooks posteriorly to the superior mesenteric vessels as these travel from behind the pancreas into the root of the mesentery.Posteriorly lie the inferior vena cava, the commencement of the portalvein, the aorta, the superior mesenteric vessels, the crura of the diaphragm, the coeliac plexus, the left kidney and the suprarenal gland. The tortuous splenic artery runs along the upper border of the pancreas. The splenic vein runs behind the gland, receives the inferior mesenteric vein and joins the superior mesenteric to form the portal vein behind the pancreatic neck.

Anteriorly lies the stomach separated by the lesser sac. To the left, the pancreatic tail lies against the hilum of the spleen.

The spleen

• The spleen is approximately the size of the cupped hand. It forms the left lateral extremity of the lesser sac. Passing from it are the gastrosplenic ligament to the greater curvature of stomach (carrying the short gastric and left gastro-epiploic vessels) and the splenorenal ligament to the posterior abdominal wall (carrying the splenic vessels and the tail of the pancreas).

Relations• Posteriorly – the left diaphragm, separating it from the pleura, left lung and the 9th, 10th and 11th ribs.• Anteriorly – the stomach.• Inferiorly – the splenic flexure of the colon.• Medially – the left kidney.The tail of the pancreas abuts against the hilum of the spleen throughwhich vessels and nerves enter and leave this organ.

CLINICAL FEATURES• 1 In performing a splenectomy the close relationship of the

pancreatic tail to the hilum and splenic pedicle must be remembered; it is easily wounded.2 Note the close proximity of the lower ribs, the lowest part of the left lung and pleural cavity, the left diaphragm, the left kidney and the spleen; injuries to the left upper abdomen may damage any combination of these structures. Similarly, a stab wound of the posterior left chest may penetrate the diaphragm and tear the spleen. The spleen, with its thin tense capsule, is the commonest intra-abdominal viscus to be ruptured by blunt trauma.3 Accessory spleens