Page 108 - Clinical Anatomy

ECA2 7/18/06 6:42 PM Page 93

The gastrointestinal adnexae 93

tine in such a case is left as a narrow pedicle, which allows volvulus of the
whole small intestine to occur (volvulus neonatorum).
4◊◊Occasionally, reversed rotation occurs, in which the transverse colon
comes to lie behind the superior mesenteric vessels with the duodenum in
front of them; this may again be accompanied by extrinsic duodenal
obstruction due to a peritoneal fold.
5◊◊Exomphalos is persistence of the mid-gut herniation at the umbilicus
after birth.

The gastrointestinal adnexae:
liver, gall-bladder and its ducts,

pancreas and spleen

The liver (Fig. 71)
This is the largest organ in the body. It is related by its domed upper surface
to the diaphragm, which separates it from pleura, lungs, pericardium and
heart. Its postero-inferior (or visceral) surface abuts against the abdominal
oesophagus, the stomach, duodenum; hepatic flexure of colon and the right
kidney and suprarenal, as well as 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 (Fig. 71b and c):
•◊◊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 liga-
mentus 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 con-
tinuous in the adult. See also fetal circulation page 38.
Lying in the porta hepatis (which is 2in (5cm) long) are:
1◊◊the common hepatic duct—anteriorly;
2◊◊the hepatic artery—in the middle;
3◊◊the portal vein—posteriorly.
As well as these, autonomic nerve fibres (sympathetic from the coeliac