794 URINARY ORGANS. 



rior surface rests upon the crus of the Diaphragm, opposite the tenth dorsal 

 vertebra. The upper thin convex border is directed upwards arid inwards. The 

 lower thick concave border rests upon the upper end of the kidney, to which it 

 is connected by areolar tissue. The inner border is in relation with the great 

 splanchnic nerve and semilunar ganglion, and lies in contact on the right side 

 with the inferior vena cava, and on the left side with the aorta. 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 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, and 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, formerly given to these organs. In the 

 centre is often seen a space formed by the breaking down of the component 

 parts of the tissue. . % 



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

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

 inch in diameter, and consists of small closed parallel tubes of limitary mem- 

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

 and nucleated cells. According to Ecker, the apparently tubular canals con- 

 sist 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, which, from being situated endwise, 

 present the appearance of linear tubes. Nucleated cells exist in large numbers 

 in the suprarenal glands of ruminants, more sparingly in man and other animals, 

 but the granular matter appears to form the chief constituent of the gland ; the 

 granules vary in size, and they present the singular peculiarity of undergoing 

 no change when acted upon by most 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 suprarenal capsules are numerous and of large size, 

 they 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 suprarenal 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 pneurnogas- 

 tric 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, cov- 

 ered 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 visceral layer of the pelvic fascia, which is reflected from the wall of 

 the pelvis on to the viscera. 



Contents. The viscera contained in this cavity are the urinary bladder, the 



