“ae 
left mipple. If these pomts be joined by three lines, shehtly concave towards 
the liver, they will give the outline of the organ with sufficient accuracy for all 
ordinary purposes. (For variations in position see p. 1067.) 
1060 THE DIGESTIVE SYSTEM. 
Or in more detail:—if the two “impple points” (a) and (e) be jomed by a line, slightly 
convex upwards on each side, but a little depressed at the centre corresponding to the position 
of the heart, and crossing the lower end of the sternum about the level of the sixth cartilage, 
it will mark the upper limit. A line, convex outwards, from the right nipple point (a) to the 
subcostal point (b) will indicate the right limit, while the lower limit is marked by a line, 
convex downwards, drawn from the subcostal point (6) to the left nipple point (c), and passing 
through a point half-way between the umbilicus and the lower end of the gladiolus, in the 
middle line. 
The line indicating the upper limit of the liver is elevated on each side, corresponding to the 
cupolie of the diaphragm, and depressed in the centre beneath the heart. On the right side 
where highest, namely, about one inch (25 mm.), internal to the mammary line, it reaches during 
expir gion to the upper border of the fifth rib; on the left side it is one- -half to three-quarters of 
an inch (12 to 18 mm.) lower; and it crosses behind the sternum at the level of the sixth sterno- 
costal HReee ea sometimes lower. It must be remembered, however, that, whilst the liver 
reaches up to the levels just given, it does so only at the highest part of its convex parietal surface, 
and is separated from the ribs all round by the thin lower margin of the lung (which extends 
down between the chest wall and diaphragm to the sixth rib in front, to the eighth in the mid- 
lateral line, and to the level of the tip of the spine of the tenth dorsal vertebra behind), so that, in 
pereussing over the liver, its dulness is obscured by the resonance of the lungs above these points. 
Weight and Size.—The liver usually weighs from three to three and a quarter 
pounds, or about sth of the body weight. 
The average size of the liver may be briefly expressed as follows :—It measures in the trans- 
verse direction about seven inches (17°5 cm.) ; in the vertical, six to seven inches (15 to 175 cm.); 4 
and in the antero-posterior, on the right side where ereatest, about six inches (15 em.) Its 
greatest width, measured obliquely from side to side along the inferior or visceral surface, is ten 
inches (25 em.) 
Its weight ordinarily varies between fifty and fifty-five ounces in the male, and between forty- 
three and forty-eight in the female, with an average for the two sexes of about forty-nine ounces, 
ora little over three pounds. It corresponds to about 3!,th of the body weight in the adult ; whilst 
at birth it is relatively twice as large (viz. ;'sth or sth of the body weight), and in the early 
foetus very much larger. 
The proportion of the right to the left lobe is very variable, but is usually about as 4 to 1; 
at birth it is about as 2 or 3 to 1. 
Relations and Surfaces.—The liver, as already pointed out, possesses two chief 
surfaces, the parietal lying in contact with the abdominal parietes, and the visceral 
resting on the abdominal viscera. 
Parietal Surface.—In conformity with the shape of the upper portion of the 
abdominal cavity which it occupies, the parietal surface (Fig. 715) is convex in 
general outline, and, taken as a whole, hes against the diaphr agi, except below 
and in front, where it projects from beneath the ribs (Fig. 714), and comes in 
contaet with ihe anterior abdominal wall for about two or ‘tats inches (5:0 to 7°5 
em.) below the xiphi-sternal articulation. It is completely covered by peritoneum, 
except behind at the “uncovered area,’ where it comes into direct relation with 
the diaphragm ; and it is divided into right and left lobe-portions by the attach- 
ment of the falciform ligament—a fold of peritoneum which connects it to the 
diaphragm and anterior abdominal wall. 
As the space which the hyer occupies is bounded by the anterior, the right, 
and the posterior walls of the abdomen, as well as by the roof, we can distinguish 
on its parietal surface, which hes against, and takes its shape from, these walls, 
four corresponding “areas,” namely (a) the superior, (>) the anterior, (c) the right, 
and (d@) the posterior areas of the parietal surface. Of these the posterior area is 
the most important, and must be described in greater detail than the others. 
Posterior Area, or back, of the Parietal Surface.—This portion of the parietal 
surface (which corresponds to the posterior surface of His) is directed back- 
wards, and les in contact with the diaphragm, here passing down on the 
posterior abdominal wall. It is very irregular in shape, and presents from right 
to left the following parts :—(1) The “uncovered area” or the right lobe; (2) the 
suprarenal impression; (3) the fossa of the vena cava; (4) the Spigelian lobe, 
separated by the fissure of the ductus venosus from (5) the cesophageal groove, 
which belongs to the left lobe. 
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