1728 HUMAN ANATOMY. 



remembered in obscure cases before basing a diagnosis upon the situation of the 

 external wound. 



In bleeding from the liver after either rupture or stab wound, or during opera- 

 tions, temporary occlusion of the portal vein and hepatic artery may be secured by 

 pressing them between the finger and thumb, the former being placed just within 

 the foramen of Winslow and the latter externally on the gastro-hepatic omentum. 



Enlargement of the liver, if uniform (congestion, multiple abscess, perihepatitis, 

 fatty degeneration, hypertrophic cirrhosis), causes a bulging of the right lower ribs 

 and their cartilages and an increase of the area of absolute percussion dulness. The 

 upper limits of the latter should normally be found at the sterno-xiphoid junction in 

 the median line, the sixth intercostal space in the right mammary line, the seventh 

 rib in the axillary line, and the lower border of the ninth rib in the scapular line. 

 A modified dulness is obtained posteriorly over the area where the lung overlaps the 

 liver, down to the level of the ninth rib. The lower level of the dulness and thus 

 of the liver itself is in the mid-line, half-way between the sterno-xiphoid junction 

 and the umbilicus, at or a little below the costal margin in the mammary line, on a 

 level with the tenth and eleventh ribs laterally and opposite the eleventh dorsal ver- 

 tebra posteriorly. At this point it is continuous with the lumbar dulness due to the 

 thickness of the spinal muscles, the quadratus lumborum, the kidneys, and the 

 perirenal fat. 



In localized enlargements, as from tumor, abscess, or hydatids occupying the 

 upper surface of the right lobe, the diaphragm is pushed upward and the upper 

 limit of the percussion dulness raised, the lower limit remaining temporarily unaf- 

 fected, the area of dulness being thus increased. 



In emphysema or pneumothorax both limits are lowered (as they are also in 

 empyema, although in that condition the liver-dulness merges into that of the pleural 

 abscess), and in phthisis, collapse or retraction of the lung, or abdominal meteor- 

 ism both limits are raised, the total area of dulness remaining unchanged in these 

 cases. Of course, in atrophic disease the area is diminished and, as in cases in 

 which the whole liver is drawn or pushed up, or there is free gas in the abdominal 

 cavity, there may be tympany over the right lower ribs. 



Abscess of the liver may be due to infection through the portal system, as from 

 dysentery or hemorrhoids, or from typhoid fever, colitis, or appendicitis ; or through 

 the general blood-supply, as from osteomyelitis or cranial trauma. In addition to 

 the usual symptoms of suppuration, it, like many other liver troubles, is sometimes 

 characterized by pain in or above the right shoulder. This is thought to be 

 explained by the facts that (a) the right lobe is far more commonly affected, (6} 

 the phrenic contributes to the nerve-supply to the liver and is derived partly from 

 the fourth cervical, and (c) the supra-acromial nerve is a branch of the latter. 

 Other evidence showing relations between the supra-acromial and phrenic nerves, 

 e.g. , hiccough in shoulder arthritis, makes this explanation seem reasonable. 



Hepatic abscess may open (a) inferiorly into the stomach, colon, duodenum, or 

 right kidney, or into some portion of the peritoneal cavity, either the subhepatic 

 space, the general cavity, or the lesser cavity via the foramen of Winslow ; () 

 superiorly into the pleura, lung, or bronchi, or into the pericardium ; (r) posteri- 

 orly into the retroperitoneal space and the loin ; (d) anteriorly on the surface of 

 the body, sometimes following the remains of the umbilical vein to the umbilicus. 



The resistance of the ribs, intercostal muscles, and diaphragm makes pointing 

 in other directions of rare occurrence. Pus may invade the suprahepatic (subdia- 

 phragmatic) space or the liver itself from above the diaphragm. Many empyemas 

 have taken this course. Nephric or perinephric abscess on the right side may 

 extend to the liver. 



Hvdatid cysts are more common in the liver than elsewhere, as the embryo of 

 the egg of the ta^nia echinpCOOCUS, freed from its shell by digestion, readily pene- 

 trate-, the ^.iMrir and intestinal vessels, and is very likely to enter a tributary of the 

 portal system and thus ho carried direct to the liver, where it multiplies and 

 develops into the mature hvdatid. Spontaneous evacuation of the cysts may occur 

 in any of tin- directions alreadv mentioned. 



In opening an hepatic abscess or hydatid cyst the liver must be reached, as in 



