444 



ABDOMEN 



filled with Urine. The neck of the bladder is firmly fixed in 

 position by its attachment to the prostate and by its connec- 

 tion with the upper fascia of the pelvic diaphragm, and the 

 prostate is securely held in place by its strong sheath of pelvic 

 fascia; therefore, as the bladder becomes filled, the internal 

 urethral orifice suffers very little change of position. It is 

 only in cases of excessive distension that any marked change 

 in its level becomes manifest, and under such circumstances 

 the internal urethral orifice sinks, to a certain extent, in the 

 pelvic cavity. 



As the bladder fills, its superior wall is raised from the 

 fundus and infero-lateral walls. All its surfaces are increased 

 in area, and the borders, which in the empty bladder inter- 

 vene between them, become rounded off and finally obliterated. 

 The organ thus becomes oval in form, and the walls, which 

 are thick and firm in the contracted state, become com- 

 paratively thin. The apex appears above the symphysij 

 pubis, and, as distension goes on, the organ rises higher an< 

 higher into the hypogastric region until a considerable extent 

 of its wall becomes applied to the abdominal wall above th< 

 pubis. The infero-lateral surfaces of the distending bladder 

 encroach on the paravesical fossae, and finally obliterate them, 

 thus coming into contact with a greater extent of the sid< 

 walls of the pelvis. 



When the bladder is excessively distended it assumes 

 spherical form or, in some cases, an ovoid form, with the 

 large end above (Figs. 202, 211). In the latter case its lonj 

 axis is no longer horizontal, but oblique, being directed froi 

 above downwards and backwards. 



When the urine is ejected from the bladder, the superior 

 wall descends till it becomes approximated to the infero- 

 lateral walls and the fundus. The viscus, therefore, becomes 

 flattened from above downwards, and comes to lie again 

 entirely within the cavity of the pelvis minor. When such 

 bladder is examined in a median section, in a subject from 

 whom the urine was expelled shortly before death, the walls 

 of the bladder are thick and firm, and the lumen of the 

 viscus may be reduced to a mere slit. The part of the 

 lumen which lies behind the internal urethral orifice is called 

 the posterior limb, and the part in front of the orifice, 

 bounded by the approximated superior and infero-lateral 

 walls, is called the anterior limb of the cavity. The anteri< 



