THE LIVER 1195 



depth. On the other hand, a distended state of the small intestines, with a contracted stomach 

 and colon, may have the opposite effect, flattening it from below upwards and enlarging it in 

 the transverse direction. 



Variations in form and position due to malformations of the thoracic framework, either con- 

 genital or acquired, are very common, particularly in females as a result of tight-lacing, which 

 presses the lower ribs inwards. Sometimes in these cases the constriction of the waist lies 

 chiefly below the liver. The organ is then forced up against the diaphragm, filling its whole vault, 

 and extending across to the left abdominal wall, where its left margin may lie in the interval 

 between the diaphragm and the spleen. But more commonly it would seem that the liver is 

 caught by the constriction : its upper part is then closely pressed into the vault of the diaphragm, 

 which, owing to the narrowing of the thorax, is unable to accommodate the whole organ, so 

 that its inferior part is crushed down for a considerable distance into the umbilical zone of the 

 abdomen (Fig. 918, p. 1167), particularly on the right side. Often, too, a wide, tongue-like 

 process (the so-called "Reidel's lobe") descends from the inferior margin, lateral to the gall- 

 bladder. This process, which when very large may reach to the iliac crest, is sometimes found 

 in men, although more common in women, and is liable to be mistaken for a tumour. A some- 

 what similar process occasionally descends from the left lobe. 



Again, in apparently healthy bodies the liver may extend up on the right side almost to the 

 fourth rib ; whilst in other cases it may be as low as the sixth rib, or even lower. Nor is it 

 rare particularly in females to find the anterior border projecting two or three inches (5'0 to 7 '5 

 cm.) below the margin of the thorax on the right side (Fig. 918, p. 1167). 



Reference should be made here to certain grooves often seen on the liver. Some of these are 

 found running obliquely low down at the right side where the liver is in contact with the ribs ; 

 they are particularly common in females, and are due to the pressure of the ribs resulting from 

 tight-lacing. Grooves of a different kind are found at the superior part of the parietal surface ; 

 where the liver is in contact with the diaphragm ; these usually run radially, that is, in the 

 direction of the muscular fibres of the diaphragm, and are apparently produced by a wrinkling, 

 or irregular contraction, of the diaphragm. At least, ridges of the diaphragm are found lying in 

 the grooves, and these ridges or wrinkles would seem to be responsible for the production of the 

 grooves. 



Finally, the liver may present certain congenital irregularities in the direction of additional 

 fossae and lobes, which reproduce the conditions found in the higher apes, and are very 

 commonly present in the foetus (Thomson). Or the liver may be divided up into a large number 

 of distinct lobes, as in most other animals. 



Changes in position have been already referred to in connexion with variations in form ; 

 there need only be added here that the liver ascends and descends at every expiration and inspira- 

 tion respectively, and that it also descends, but very slightly, in changing from the reclining to 

 the erect posture. Occasionally, without any evident cause, the liver and diaphragm are found 

 to occupy a higher or lower position than usual. 



Fixation of the Liver. At first sight it is not easy to understand the means by which 

 the liver maintains its position in the abdomen (and the same remark applies, perhaps, to other 

 solid abdominal organs). The falciform ligament gives it no support, as it is quite lax when 

 in the body. Nor can it be said that its vessels, except perhaps the hepatic veins, assist. 

 However, on considering the conditions under which the viscera are placed in the abdominal 

 cavity the problem becomes less difficult. 



The abdomen is a closed cavity, with a firm framework to its superior part, a tightly stretched 

 diaphragm for its roof, and muscular walls all round. Into the concavity of this roof the parietal 

 surface of the liver is fitted with perfect accuracy, so that the two are in absolute contact, and 

 cannot be separated without producing a vacuum, unless some other structure is in a position to 

 fill the space. But there is hardly any other viscus movable enough to pass up over the front 

 of the liver into the vault of the diaphragm, so that atmospheric pressure alone is probably 

 sufficient to retain the organ in situ, as in the case of the shoulder joint. In addition, the abdominal 

 muscles are always in a condition of tonic contraction or " tone," which gives rise to an intra- 

 abdominal pressure. This is effective in all directions, and consequently there is a considerable 

 pressure on all the abdominal walls. The liver, being in absolute contact with the roof, may be 

 considered a part of this wall, and it is consequently affected by this pressure which helps to 

 sustain it. Add to this, the support which the organ receives from the intestines, the stomach, 

 and the pancreas ; from the coronary and triangular ligaments ; from the connexion of the back of 

 the right lobe by areolar tissue to the diaphragm ; and, finally, from the inferior vena cava 

 embedded in the liver and sending its hepatic veins forwards to all parts of the organ, just 

 before the vein itself is firmly attached to the margins of the caval orifice in the central tendon 

 of the diaphragm, and we will probably find sufficient cause for the maintenance of the organ 

 in its position in the abdominal cavity. 



Relation to Peritoneum. The relation of the liver to the peritoneum is some- 

 what complex in its details. The greater part of the liver is covered with peri- 

 meum, forming the tunica serosa, but there is an area of some size upon its superior 

 id posterior aspects where it is directly in contact with the diaphragm, and round 

 margins of this area the peritoneum passes from liver to diaphragm. This is 

 lown as the bare area, and the peritoneum around this area is known as the 

 famentum coronarium (coronary ligament). Further, the liver is attached to the 



