THE ABDOMINAL CAVITY. 161 



Cortical Substance, composed of columnar and rounded cells, held together 



in layers by a fibrous stroma. 

 Medullary Substance, -is darker than the cortical portion, and pulpy. 



Consists of cells in groups, supported by a delicate stroma, and believed 



by some anatomists to be prolonged into nerve fibres. 



What are their Relations ? Their bases rest on the upper front parts of 

 the kidneys, their posterior surfaces on the crura of the diaphragm, about the 

 level of the loth dorsal vertebra. The 



Anterior Surface, of the right capsule is covered by the liver; that of the 



left one by the spleen and pancreas. 



Superior Surface, of each is in relation internally with the great splanchnic 

 nerve and semilunar ganglion. 



Name their Vessels and Nerves. The Lymphatics of these bodies 

 open into the lumbar glands, but are very imperfectly known. Their 



Arteries, are the Supra-renal Branches of the aorta, renal, and inferior 

 phrenic arteries, forming a dense capillary plexus in the cortical portion 

 of the organ. 



Veins, of each open into a single trunk, the Supra-renal Vein, which on 

 the right side of the body empties into the inferior vena cava, on the left 

 side into the left renal vein. 



Nerves, are chiefly derived from the solar and renal plexuses, with some 

 filaments from the phrenic and pneumogastric nerves, forming a compli- 

 cated network in the medullary substance of the organ, and having 

 numerous small ganglia developed upon them. 



THE ABDOMINAL CAVITY. 



What is the Abdomen ? An oval cavity, situated between the thorax 

 above and the pelvis below, invested by peritoneum internally, and containing 

 the 



Stomach. Pancreas. Abdominal Aorta. 



Intestines. Kidneys and Ureters. Inferior Vena Cava. 



Liver. Supra-renal Capsules. Receptaculum Chyli. 



Gall-bladder. Bladder (when distended.) Thoracic Duct. 



Spleen. Uterus (during pregnancy.) Solar Plexus, etc. 



Name the Boundaries of the Abdomen. Above, it is bounded by the 

 diaphragm; below, by the brim of the pelvis; -posteriorly, by the vertebral 

 column, and the fasciae covering the psose and quadrati luvnborum muscles ; 

 anteriorly and laterally, by the transversalis fascia, the lower ribs, and the 

 venter of the ilium. 

 K 



