358 



DISSECTION OF THE ABDOMEN. 



Consists of 

 two parts, 



with a 



fibrous 



capsule. 



Cortical 



and 



medullary 

 parts. 



Arteries. 

 Veins. 



Nerves. 

 Lymphatics 



right capsule, beside the vena cava is the solar plexus ; and internal 

 to the left are the aorta, with the coeliac axis, and the solar plexus. 



Obvious structure. A vertical section of a fresh suprarenal body 

 shows it to be formed of an external or cortical layer, and an 

 internal or medullary substance. The whole is surrounded by a 

 thin fibrous capsule, which sends processes into the interior, and 

 along the blood-vessels. 



The cortical part is of a deep yellow colour, and firm. It forms 

 about two-thirds of the thickness of the whole body, and in the 

 section appears striated perpendicularly to the free surface of the 

 organ. The medullary part is dark brown or nearly black, and very 

 soft and pulpy. If the specimen is not fresh, it may look as if the 

 cortical part enclosed a cavity. 



Blood-vessels. Numerous arteries are furnished to the suprarenal 

 bodies. Generally there are three vessels, one directly from the 

 aorta, and one each from the diaphragmatic and renal arteries. 

 Their small branches penetrate the organ at many spots of its circum- 

 ference. The veins are for the most part collected into one long 

 trunk, which issues by the hilum, and opens on the right side into 

 the vena cava, on the left into the renal vein. Other smaller veins 

 pass out through the cortex to the renal vein and the vena cava. 



Nerves. The nerves are very numerous and large, and come from 

 the solar plexus. 



Lymphatics are superficial and deep ; both join those of the 

 kidnev. 



To see the 

 diaphragm. 



arches. 



Diaphragm 



situation 

 and form ; 



origin at 

 the circum- 

 ference ; 



THE DIAPHRAGM WITH AORTA AND VENA CAVA. 



Dissection. The student will now clean, first the diaphragm, 

 then the large vessels and their branches, and afterwards the deep 

 muscles of the abdomen. For the dissection of the diaphragm it will 

 be necessary to remove the peritoneum, defining especially the 

 central tendinous part, and the strong processes or pillars which are 

 fixed to the lumbar vertebrae. While cleaning the muscle the 

 student should be careful of the vessels and nerves on its surface, 

 and of others in and near the pillars. The right kidney and 

 suprarenal will be drawn downwards or thrown over to the left in 

 cleaning the diaphragm, but their vessels should be preserved. 



On the right side two aponeurotic bands or arches near the spine, 

 which give attachment to the muscular fibres, should be dissected ; 

 one curves over the internal muscle (psoas) ; the other extends over 

 the external muscle (quadratus lumborum), and will be made more 

 evident by separating it from the fascia covering the muscle. 



The DIAPHRAGM or midriff (fig. 137, A p. 360) forms the vaulted 

 movable partition between the thorax and the abdomen. It is 

 fleshy externally, where it is attached to the surrounding ribs and 

 the spinal column, and tendinous in the centre. 



The origin of the muscle is at the circumference, and is alike on 

 both sides. Thus, it arises on each side by fleshy slips from the inner 

 surface of the ensiform process and the six lower rib cartilages ; from 



