414 



THE SUPEAEEXAL CAPSULES. 



as to form two sides of a triangle. The lower border is concave, and 

 rests upon the anterior and inner part of the summit of the kidney, to 

 which it is connected by loose areolar tissue : it is thick, and almost 

 always deeply grooved. The posterior surface rests upon the diajihragm. 

 Its anterior surface is covered on the right side by the liver, and on the 

 left by the pancreas and spleen : it presents an irregular fissure named 

 the hilus, from which the suprarenal vein emerges (fig. 300, v). The 

 right capsule, like the right kidney, is placed lower down than the left. 



Fig. 300. 



Fig. 299. — Fkont view of the Right Kidney and Suprarenal Body of a full- 

 grown FcETus (Allen Thomson). 



This figure shows the lobulated form of the fcetal kidney, r ; v, the renal vein and 

 artery ; ?(, the ureter ; s, the suprarenal capsule, the letter is placed near the sulcus in 

 which the large veins {v') are seen emerging from the interior of the organ. 



Fig. 300.— Section of the Suprarenal Body. 



A vertical section of the suprarenal body of a foetus, twice the natural size, showing 

 the lower notch by which it rests on the summit of the kidney, and the anterior notch l>y 

 which the veins issue, together with the distinction between the medullary and cortical 

 substance. 



The suprarenal capsules vary in size in different individuals, and the 

 left is usually somewhat narrower at its base, but longer from above 

 downwards, and larger than the right. They measure from an inch and 

 a quarter to an inch and three-quarters in height, and about an inch 

 and a quarter in width ; their thickness is from two to three lines. 

 The tveigM of each in the adult is from one to two drachms. 



Structure. — Besides a covering of areolar tissue mixed frequently 

 with much fat, the suprarenal capsules have a thin fibrous investment. 

 On the exterior their colour is yellowish or brownish-yellow. When 

 divided (fig. 300), they are seen to consist of two substances : one, 

 external or cortical, is of a deep yellow colour, firm and striated, and 

 forms the principal mass of the organ ; the other, internal or medullary, 

 is in the adult of a dark brownish-black hue, and so soft and pulpy that 

 some anatomists have erroneously described a cavity within it. 



