ABDOMEN. 



(Fig. 5.) 



prominent anteriorly, and the continuity of the 

 abdominal and pelvic cavities is thus clearly 

 shewn. It is useful to examine the relations 

 of the axes of these two cavities ; that of the 

 pelvis passes forwards and upwards towards 

 the umbilicus, while the axis of the abdomen 

 passes from above downwards and forwards 

 so as to terminate a little above the pubis, 

 the two axes accordingly would intersect each 

 other a little below the umbilicus at an obtuse 

 angle. This angle may be obliterated by 

 bringing the pelvis very much forward and 

 producing a full flexion of the spine, and hence 

 in all efforts for expulsion that attitude is almost 

 instinctively assumed which shall identify the 

 axes of the two cavities, and thus direct the 

 efforts in the most favourable manner. The 

 ordinary form of the cavity in the adult male is 

 oval, but it presents some slight differences in 

 the female and in the fetus ; and these differ- 

 ences are dependent on the great or incomplete 

 development of the pelvis. In the female the 

 abdomen is generally more capacious than in 

 the male ; and this greater size is more remark- 

 able at the inferior part of it in the hypogastric 

 region. In fact in the male it would seem that 

 the great extremity of the oval is toward the 

 thorax, and its smaller one towards the pelvis ; 

 but in the female it is just the reverse, the 

 larger extremity being toward the pelvis. It 

 should be observed, however, that the modern 



fashion of tightly compressing the lower part of 

 the thorax has a material effect on the external 

 characters of the female abdomen, otherwise 

 there is no reason that the superior part of it 

 should be proportionally less than in the male. 

 In the foetus the abdomen is proportionally larger 

 than at any other period of life : this is to be 

 attributed to the imperfect development of the 

 pelvis, and likewise to the great size which 

 some of the abdominal viscera possess ; and as 

 some time must elapse before the pelvis reaches 

 its full dimensions, or the viscera lose their 

 superfluous parts, the abdomen continues of this 

 large size for a long period after birth. 



The subdivision of the abdomen into regions 

 is especially useful in reference to the contents 

 of the abdominal cavity, which it is highly de- 

 sirable the student should examine, so as to be 

 able to assign to each compartment its appro- 

 priate contents. The abdominal viscera may 

 be subdivided into the membranous and the 

 parenchymatous ; the former being such as the 

 stomach and intestinal canal, the latter, such as 

 the liver, spleen, pancreas, &c. The viscera 

 have likewise been distinguished in reference 

 to their position with respect to the peritoneum, 

 by the names intra-peritoneal and extra-peri- 

 toneal ; but it is sufficient to know that no 

 serous membrane contains any organ within it 

 (i. e. within its sac) to see the error of such a 

 distinction. But we cannot adopt a better di- 

 vision of the abdominal viscera than that which 

 has reference to the functions of those organs, 

 and which Beclard has adopted : viz. 1. the 

 organs of digestion the stomach, the intes- 

 tinal canal, the liver and its appendages, the 

 spleen, and the pancreas: 2. the urinary organs 

 the kidneys and the ureters, to which may 

 be added from their close relation to the kid- 

 neys, the suprarenal capsules : 3. the organs of 

 generation in the male the vasa deferentia, and 

 in the male foetus at the sixth or seventh month 

 of intra-uterine life, the testicles : none of 

 the organs of generation can strictly be said to 

 be abdominal organs in the female. In both 

 male and female the other internal generative 

 organs are pelvic viscera. If we add to the 

 above enumeration of parts the abdominal por- 

 tion of the aorta, its primary subdivision into 

 the common iliacs ; the anterior subdivision of 

 these arteries under the name of external iliacs ; 

 the branches of the aorta which are distributed 

 to the viscera as well as to the walls of the 

 abdomen ; the common and external iliac veins; 

 the venacava ascendens; the system of the vena 

 portae ; the abdominal portion of the sympa- 

 thetic system of nerves, both that which follows 

 the arterial ramifications, and that which is the 

 continuation of the chain of ganglia that lies 

 along the spine, the termination of the par 

 vagum ; the mesenteric glands, and the lacteals ; 

 the lymphatics and their ganglia which lie 

 along the spine ; the origin of the thoracic duct, 

 a portion of the course of that duct ; these will 

 complete the list of parts contained in the abdo- 

 minal cavity. 



The full particulars of the relative positions of 

 the contents of the abdomen, and the abnormal 



c 2 



