344 



DISSECTION OF THE ABDOMEN. 



Serous coat 



nearly 



complete. 



Fibrous coat 

 sends in- 

 wards pro- 



structure. 



Interior of 

 spleen, 



disposition 

 of fibrous 



to form an 



areolar 



structure. 



Pulp of 



Malpighian 

 bodies. 



Splenic 

 artery : 



ending ; 



no anasto- 



Vein begins 

 by open 



branches 

 anastomose. 



Lymphatics 



Nerves. 



The serous or peritoneal coat encases the spleen, covering the 

 surface except at the hilum and the ridge behind. It is closely 

 connected to the subjacent fibrous coat. 



The fibrous coat (tunica propria) gives strength to the spleen, 

 and forms a complete case for it. At the hilurn this investment 

 passes into the interior with the vessels, to which it furnishes 

 sheaths ; and if an attempt is made to detach this coat, numerous 

 fibrous processes will be seen to be connected with its deep surface. 

 Its colour is whitish; and it is made up of areolar and elastic 

 tissues. 



Dissection. The spongy or trabecular structure will best appear 

 by washing and squeezing a piece of fresh bullock's spleen under 

 water, so as to remove the inner grumous-looking material. 



The trabecular tissue (fig. 130) forms a 

 network through the whole interior of the 

 spleen, similar to that of a sponge, which 

 is joined to the external casing, and forms 

 sheaths around the vessels. Its processes or 

 threads are white, flattened or cylindrical, 

 and consist of fibrous and elastic tissues, 

 with a few muscular fibres. The interstices 

 communicate freely together, and contain the 

 pulp of the spleen. 



The splenic pulp is a soft red-brown mass, 

 which is lodged in the areola3 of the trabe- 

 cular structure, and consists in great part of 

 blood. In a fresh section small whitish spots 

 (e^th of an inch in diameter) may be seen 

 scattered amongst the dark pulp : these are 

 the Malpighian corpuscles of the spleen 

 lymphoid nodules attached to the small 

 branches of the artery. 



Blood-vessels. The larger branches of the 



SPLEEN OF THE Ox. splenic artery are surrounded by sheaths of 

 fibrous tissue in the trabeculae ; but the 



smallest branches leave the sheathing, and break up into tufts of 

 capillaries, which are said to open into the fine meshes of the 

 spleen substance. There are few or no anastomoses between the 

 arterial branches in the organ. 



The splenic vein is supposed to begin in the meshes of the splenic 

 pulp by open channels. The small branches resulting from the 

 union of these radicles anastomose freely together, and unite into 

 trunks larger than the accompanying arteries, which issue by the 

 hilum of the spleen. 



Lymphatics and nerves. The lymphatics are superficial and deep, 

 and, leaving the organ at the hilum, traverse small glands lying 

 along the splenic vessels on their way to the cceliac glands. The 

 nerves come from the solar plexus, and surround the artery and its 

 branches. 



FIG. 130. TRABECULAR 

 STRUCTURE OP THE 



