SPLEEN. (Lien seu Splen, Lat.; ZrXhp, Gr. ; die 3filz, Germ.; la Rate, Fr.) Nor mal anatomy. The spleen is a single so-called " vascular gland," which is attached to the cardiac extremity of the stomach, and appears to possess some intimate connection with the renovation of the blood.
Situation and form. — The spleen has a roundish 'elongated form, or almost the shape of half an egg, and lies in the left hypochon driac region. We recognise on it two sur faces, two borders, and two extremities. The outer surface (supezficies externa seu connexa) is completely free and smooth, and often ex hibits a more or less deep, long, and oblique incisionj: it looks outwards, upwards, and back wards ; and is in contact with the left costal portion of the diaphragm, corresponding to the tenth and eleventh ribs. The inner swface (superficies interim seu concava) is directed inwards and forwards; is for the most part slightly concave, and presents, in a prolonged elevation which occupies its middle, a vertical furrow, the fissure for the vessels, or hilus lienalis, which contains many holes and de pressions, through which pass the nerves and vessels to and from the spleen. This fissure separates the concave surface into an anterior and larger, and a posterior and smaller por tion ; and it is connected by the broad, but short gastro-splenic omentum (liganzentum gastro-lienale), with the fundus of the stomach, to which the remainder of the concave surface is opposed. The upper extrenlity or head of the spleen (caput lienis), is the thicker and more obtuse of the two ; it occupies the ele vated hinder part of the eighth rib, and is con nected by a suspensory ligament (ligament= phrenico-lienale seu suspensiorunt) with the diaphragm. The lower extremity or cauda lienis, is thinner and more pointed, and is directed downwards and forwards. The an terior border (niargo anterior) is the thinner and sharper, and is free. The posterior border (nzargo °blunts) is thick and rounded, and is in contact with the lumbar portion of the diaphragm, and the anterior surface of the left suprarenal capsule. The spleen is thus least
moveable, where it is limited by the diaphragm; but much more so at the site of its attach ment to the stomach. But its situation changes with the variable positions of the diaphragm and stomach : thus, on the one hand, it de scends and rises in the states of in- and ex spiration respectively ; and, on the other hand, becomes more superficial or deeper, according as the stomach is empty or full.
Varieties of the spleen. —It is not un common to find the anterior border of the spleen, presenting one or more separate deep fissures. Also supplementary spleens (lienculi, seu hems succenturiati) are now and then ob served : according to Rosenmiiller and Giesker, more frequently in the Southern than in the Northern Germans. These are situated in the gastrosplenic ligament, and rarely in the great omentum (Morgagni, Huschke) ; they are red, of the ordinary splenic structure, and of a size which varies from a linseed to a walnut. They. are generally one or two in number, less frequently four or seven, and in a misdeveloped fcetus have even amounted to twenty-three.
The size and weight of the spleen experience great variation, not only in different indi viduals, but even in one and the same person : of this more will be said hereafter. On an average, its length is from 4 to 53/4 inches* ; its thickness from 1 to 11 inches ; and its breadth, from the anterior to the posterior border, 3 to 4 inches. According to Krause, its cubic contents range between 91 and 15 inches, with an average of 12. Its absolute weight varies from 6 to 15 oz., according to Soemmering ; from 71- to 103/4, according to Krause ; and it has a medium of about 8 oz. According to J. Reid t, between the twentieth and sixtieth years, it ranges from 6 to 10 oz. in the male, and from 3 oz. 133/4 dr. to 9 oz. 10 dr. in the female. Krause also states, that its specific gravity varies from 1.0579 to 1.0625, with an average of 1.0606.