723 URINARY ORGANS. 



inches in length, are rather less in width, and from two to three lines in thickness. 

 In weight, they vary from one to two drachms. 



Relations. The anterior surface of the right supra-renal capsule is in relation 

 with the under surface of the liver ; that of the left with the pancreas and spleen. 

 The posterior surface rests upon the crus of the Diaphragm, opposite the tenth 

 dorsal vertebra. Their upper thin convex border is directed upwards and inwards. 

 Their lower thick concave border rests upon the upper end of the kidneys, to which 

 they are connected by areolar tissue. Their inner borders are in relation with the 

 great splanchnic nerves and semilunar ganglia, and lie in contact on the right side 

 with the inferior vena cava, and on the left side with the aorta. The surface of 

 the supra-renal 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 the numerous fibrous processes and vessels which enter the organ through the 

 furrows on its anterior surface and base. 



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

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



The cortical substance forms the chief part of the organ ; it is of a deep yellow 

 color, ancV consists of narrow columnar masses placed perpendicularly to the 

 surface. 



The medullary substance is soft, pulpy, and of a dark brown' or black color ; 

 hence the name, atrabiliary capsules, given to these organs. In its centre is often 

 seen a space formed by the breaking down of its component parts. 



According to the researches of Oesterlen and Mr. Simon, the narrow columnar 

 masses of which the cortical substance is composed measure about ?^th of an 

 inch in diameter, and consist of small closed parallel tubes of limitary membrane 

 containing dotted nuclei, together with much granular matter, oil globules, and 

 nucleated cells. According to Ecker, the apparent tubular canals consist of rows 

 of closed vesicles placed endwise, so as to resemble tubes ; whilst Kolliker states, 

 that these vesicles are merely loculi or spaces in the stroma of the organ, having 

 no limitary membrane, and, from being situated endwise, present the appearance 

 of linear tubes. Nucleated cells exist in large numbers in the supra-renal glands 

 of ruminants, but more sparingly in man and other animals, but the granular 

 matter appears to form their chief constituent; the granules vary in size, and they 

 present the singular peculiarity of undergoing no change when acted upon by 

 most of the chemical reagents. The columnar masses are surrounded by a close 

 capillary network, which runs parallel with them. 



The medullary substance consists of nuclei and granular matter, uniformly 

 scattered throughout a plexus of minute veins. 



The arteries supplying the supra-renal glands are numerous and of large size, 

 and are derived from the aorta, the phrenic, and the renal ; they subdivide into 

 numerous minute branches previous to entering the substance of the gland. 



The supra-renal vein returns the blood from the medullary venous plexus, and 

 receives several branches from the cortical substance ; it opens on the right side 

 into the inferior vena cava, on the left side into the renal vein. 



The lymphatics terminate in the lumbar glands. 



The nerves are exceedingly numerous; they are derived from the solar and renal 

 plexuses, and, according to Bergmann, from the phrenic and pneumogastric nerves. 

 They have numerous small ganglia developed upon them. 



THE PELVIS. 



The Cavity of the Pelvis is that part of the general abdominal cavity which is 

 below the level of the linea ilio-pectinea and the promontory of the sacrum. 



Boundaries. It is bounded, behind, by the sacrum, the coccyx, and the great 

 sacro-sciatic ligaments ; in front and at the sides, by the pubes and ischia, covered 

 by the Obturator muscles; above, it communicates with the cavity of the abdomen; 

 and below, it is limited by the Levatores ani and Coccygei muscles, and the 



