THE SUPRARENAL CAPSULES. 997 



Relations. The relations of the suprarenal capsules differ on the two sides of 

 the body. The right suprarenal is roughly triangular in shape, its angles pointing 

 upward, downward, and outward. It presents two surfaces for examination, an 

 anterior and a posterior. The anterior surface presents two areas, separated by a 

 furrow, the hilum : one area occupying about one-third of the whole surface, is 

 situated above and internally ; it is depressed, uncovered by peritoneum, and is in 

 contact in front with the posterior surface of the right lobe of the liver, and along 

 its inner border with the inferior vena cava; the remaining area is elevated, 

 and is divided into a non-peritoneal portion, in contact with the hepatic flex- 

 ure of the duodenum, and a portion covered by peritoneum forming the hepato- 

 renal fold. The posterior surface is slightly convex, and rests upon the Dia- 

 phragm. The base is concave, and is in contact with the upper end and the adja- 

 cent part of the anterior surface of the kidney. The left suprarenal is crescentic 

 in shape, its concavity being adapted to the upper end of the left kidney. It 

 presents an inner border which is convex, and an outer which is concave ; its 

 upper border is narrow, and its lower rounded. Its anterior surface presents two 

 areas : an upper one, covered by the peritoneum forming the lesser sac, which 

 separates it from the cardiac end of the stomach and to a small extent from the 

 superior extremity of the spleen ; and a lower one, Avhich is in contact with the 

 pancreas and splenic artery, and is therefore not covered by the peritoneum. 

 Its posterior surface presents a vertical ridge, which divides it into two areas. 

 The ridge lies in the sulcus between the kidney and crus of the Diaphragm, 

 while the area on either side of it lies on these parts respectively; the outer 

 area, which is thin, resting on the kidney, and the inner and smaller area rest- 

 ing on the left crus of the Diaphragm. The surface of the suprarenal gland 

 is surrounded by areolar tissue containing much fat, and closely invested by a 

 thin fibrous coat, which is difficult to remove, on account of numerous fibrous 

 processes and vessels which enter the organ through the furrows on its anterior 

 surface arid base. 



Small accessory suprarenals are often to be found in the connective tissue 

 around the suprarenals. The smaller of these, on section, show a uniform surface, 

 but in some of the larger a distinct medulla can be made out. 



Structure. On making a perpendicular section, the gland is seen to consist of 

 two substances external or cortical, and internal or medullary. The former, 

 which constitutes the chief part of the organ, is of a deep yellow color. The 

 medullary substance is soft, pulpy, and of a dark brown or black color, whence 

 the name atrabiliary capsules formerly given to these organs. In the centre is 

 often seen a space, not natural, but formed by breaking down after death of the 

 medullary substance. 



The cortical portion consists chiefly of narrow columnar masses placed perpen- 

 dicularly to the surface. This arrangement is due to the disposition of the cap- 

 sule, which sends into the interior of the gland processes passing in vertically and 

 communicating with each other by transverse bands so as to form spaces which 

 open into each other. These spaces are of slight depth near the surface of the 

 organ, so that there the section somewhat resembles a net ; this is termed the 

 zona glomerulosa ; but they become much deeper or longer farther in, so as to 

 resemble pipes or tubes placed endwise, the zona fasciculata. Still deeper down, 

 near the medullary part, the spaces become again of small extent ; this is named 

 the zona reticularis. These processes or trabeculae, derived from the capsule and 

 forming the framework of the spaces, are composed of fibrous connective tissue 

 with longitudinal bundles of unstriped muscular fibres. Within the interior of 

 the spaces are contained groups of polyhedral cells, which are finely granular in 

 appearance, and contain a spherical nucleus, and not infrequently fat-globules. 

 These groups of cells do not entirely fill the spaces in which they are contained, 

 but between them and the trabeculne of the framework is a channel which 

 is believed to be a lymph-path or sinus, and which communicates with certain 

 passages between the cells composing the group. The lymph-path is supposed 



