(From the Hebrew term jaker). The Liver; called also Aepar, the upper part erix. Immediately below the diaphragm, on the right side, is placed the liver, whose small lobe extends to the scro-biculus cordis. It is divided into two lobes, besides the lobulus Spigelii, which Hippocrates calls hypercoryfiho-ses; terminated by an obtuse margin above and behind, and an acute one before and below. The large lobe is situated on the right hypochondrium, contiguous to the diaphragm, reaching nearly as far back as the spine, and rests upon the right kidney: the small lobe runs close to the diaphragm, as far as the spleen. The convex side of the liver is usually connected to the diaphragm by three ligaments, which are continuations of the peritonaeum; one lies near the edge of the extremity of each lobe, and one in the middle, and they are accordingly called the right, and left, and middle ligaments. The liver is likewise connected to the right ala of the tendinous part of the diaphragm by a broad adhesion, which is the reflection of the peritonaeum, and is called the coronarium ligamentum. Under the great lobe, a little to the right, is the gall bladder. The smaller lobe of the liver is in the left side, distinguished above by a membranous ligament, and below by a large division in the same direction as the superior ligament,
The eminences on the concave side of the liver belong to the great lobe; the principal one is a triangular mass, situated backwards near the great division, named to-bulua Spigelii; this lobe is attached by a little peduncle to the middle of the lower side of the great lobe. The first fissure we observe, next to the great one, is a notch at the anterior part of the liver, for the reception of the ligamemary remains of the vena umbilicalis; the second fissure is towards the posterior part of the liver, between the lobulus Spigelii and the little lobe, where we observe the remains of the ductus venosus, which is afterwards inserted into the vena cava (see Foetus). Upon the right of the lobulus Spigelii, between that and the great lobe, is another fissure, in which the vena cava runs down; and the next is a transverse one, situated before the lobulus Spigelii, called porta: besides these, on the fore part of the great lobe there is a depression for the reception of the gall bladder; and we may observe on the under side of the great lobe a small cavity, where it rests on the right kidney.
From behind the pancreas a mass of vessels and nerves run up to the porta . The hepatic artery comes off from the coeliaca, and divides into two branches, one of which goes to each lobe; and the vena portae, when it arrives at the porta, likewise divides into two, one of which enters the right, and the other the left, lobe. From the duodenum and pancreas we see the pori biliarii, and ductus communis choledochus, which, at a distance from the porta, divides into two ducts, viz. the cystic, which goes to the gall bladder, and the hepatic, which again is subdivided into two, and go to their respective lobes. The vena cava, in its passage through the diaphragm, sends off several branches, especially two which go to the liver, and are called vena cava hepaticae; their office is to return the blood to the vena cava after the bile is secreted. The blood from all the viscera, except the external haemorrhoidal vessels, is returned to the vena portae, which ramifies through the liver like an artery. The lower part of this vessel is called vena porta mesenterica; and the upper hepa-tica. The greatest part of these vessels are inclosed in a membranous sheath, called, from Glisson, capsula Gliasonii. This author first described it as composed of cellular membranes and nerves, covered by the peritonaeum at their entrance, and ramifying through the liver with them; but the peritonaeum must be absolutely excluded, for the nerves, with their cellular membrane only, go through the liver. The absorbents are very numerous. The nerves arise from the intercostal and eighth pair, which come from the hepatic plexus, and enter this viscus with the vessels.
The external surface of the liver is smooth, and covered with the peritonaeum, which is connected with the liver by the cellular membrane, and by the vessels which are spread upon it. The liver is very soft, and like a piece of congealed blood; for it derives its principal consistence from the vessels. Malpighi, after injection, found it to be a congeries of folliculi, in which the vessels terminate. Ruysch thought it a congeries of vessels only in the tenderest part. The penicilli of Ruysch are a collection of vessels upon the surface; and, according to this author, the vessels do not terminate in the penicilli, but become infinitely finer; whence the structure of this viscus cannot be such as Malpighi imagined. The liver, according to the ancients, was the vol. I.
viscus wherein the chyle was converted into blood; but since the knowledge of the lacteals, and the discovery of the circulation of the blood, we know that the use of the liver is to secrete the bile. The blood comes to the liver by the hepatic artery and the vena portarum; but a greater quantity is sent by the latter than by the former, and it is from the latter, as formerly observed, that the bile is secreted. See Winslow's Anatomy, and Haller's Physiology, lecture xxvii.
The substance of the liver is chiefly formed by vessels in the form of small brushes, styled penicilli; but it has been doubted whether any follicle is interposed between the vessels of the portae and the biliary pores. It may be at least asserted, that no such have been demonstrated, and we have no reason to think that any exist.
The bile first appears in minute points, styled pori biliarii. These unite and form the hepatic duct, whose coats have no appearance of a muscular structure, but whose Internal surface contains numerous, apparently mucous follicles. We omitted to remark in its proper place, that the whole of the blood conveyed by the vena portae is not employed in the secretion of bile; for the extreme branches of this arterial vein anastomose with the branches of the hepatic vein, and in this way accumulations of blood, when bile is unnecessary, are prevented.