The Liver:
An
Overview
Bob Caruthers, CST, PhD
AST Deputy Executive Director
F
ollowing the concavity of the diaphragm, the
liver occupies much of the right upper abdomi-
nal quadrant. The largest gland in the body,
the liver represents approximately one-fortieth of
adult body weight. At its most superior point, the liver
lies behind the fifth rib in the right mammary line.
The liver's left edge terminates just below the apex of
the heart, approximately
8
cm to the left of the
median line. The liver's inferior border cuts diagonally
and at the median line passes approximately midway
between the xiphoid process and the umbilicus. The
inferior border reaches the right costal margin at the
ninth costal cartilage and continues downward and
posteriorly.
'
The liver's diaphragmatic surface is divided into
superior, anterior, right, and posterior sections. The
heart produces a shallow fossa-the cardiac impres-
sion-where it lies on the liver. The posterior and
right parts of the diaphragmatic surface are in contact
with the diaphragm and the ribs. The posterior surface
contains a sulcus through which the inferior vena
cava passes. The falciform ligament subdivides the
anterior and superior surfaces, with the anterior
surface lying against the diaphragm, costal margin,
xiphoid process, and abdominal wall. The liver's
visceral surface is separated from the superior section
by the inferior border. Posteriorly, the border is
rounded and blunt, while anteriorly, it is narrow and
sharp. The ligamentum teres notches the inferior
'
border just to the right of the median plane. The
fundus of the gallbladder rests in another shallow fossa
farther to the right. The visceral surface, which holds
the gallbladder and is indented by the inferior vena
cava posteriorly, relates to the other abdominal
structures, which project into the right upper quad-
rant. They include the right suprarenal gland, right
kidney, and the right flexure of the colon, duodenum,
and stomach. Hepatic arteries, veins, and ducts enter
and exit in the portal region, near the midline of the
visceral surface.' The liver can be subdivided into
various anatomical and functional parts. Its lobes and
segments are shown in Figure
1
on page
32.
The
lobule-the basic functional unit of the liver-will be
discussed later.
'j2
In the adult, the liver's peritoneal reflections
include the ventral mesogastrium to the anterior
abdominal wall and diaphragm, and to the stomach
and the duodenum. These reflections produce the
falciform ligament, the coronary ligament, and the left
and right triangular ligament.'
The left gastric artery may have a hepatic branch,
which passes to the left lobe of the liver. The common
hepatic artery runs along the upper border of the
pancreas and passes from behind the peritoneum of
the posterior body wall into the lesser omentum at the
upper edge of the duodenum. Branches of this artery
include the gastroduodenal, proper hepatics, and
infrequently, the right gastric. The proper hepatic
artery is a continuation of the common hepatic,
which follows the gastroduodenal branch. It typically
lies to the left of the common bile duct, which is
located anterior to the portal vein. Branches of this
The
Surgical Technologist
August
1997
3
1
