364 THE ABDOMEN AND PELVIS 



external oblique, internal oblique, and transversus are divided, 

 in turn, in the lateral part of the wound, whilst medially the 

 anterior wall of the rectus sheath is divided and the muscle is 

 retracted in a medial direction. The transversalis fascia is 

 now exposed, and the inferior epigastric artery, which may be 

 ligated if necessary, is found on its surface in the medial part 

 of the wound. 



The fascia transversalis is torn through in the neighbourhood 

 of the bladder, and the peritoneum is retracted upwards and 

 medially. In this way the abdominal viscera are kept out of 

 the field of operations and more space is obtained. When the 

 peritoneum is elevated, the external iliac vessels are exposed in 

 the posterior part of the wound, and the ductus deferens is seen 

 in front, as it descends to reach the seminal vesicles (p. 358). 

 In this part of its course the ureter is not adherent to the 

 peritoneum, but is closely related to the structures on the pelvic 

 wall. The superior vesical artery forms a convenient guide, 

 since it lies anterior to the ureter. As a small calculus, impacted 

 in the terminal portion of the ureter, may be extremely difficult 

 to feel, an assistant pushes the bladder upwards by means of 

 a finger in the rectum. The surgeon then presses the ureter 

 against the resistance thus afforded, and determines the precise 

 position of the stone. 



Calculi impacted in the vesical orifice of the ureter may be 

 removed trans-vesically (cf. removal of gall-stones impacted in 

 ampulla of Vater, p. 317). 



The Prostate consists chiefly of plain muscle fibres and 

 glandular tissue, surrounded by a fibrous capsule. The muscle 

 fibres are directly continuous with the external stratum of the 

 muscular coat of the bladder. The prostate possesses a strong 

 fibrous sheath, which is derived from the visceral pelvic fascia 

 and is quite distinct from the capsule. This sheath does not 

 intervene between the prostate and the bladder, but is carried 

 upwards on to the walls of the latter. 



In size and shape the prostate resembles a chestnut. Its 

 base is directed upwards and is partly continuous with the neck 

 of the bladder ; its apex is directed downwards and rests on the 

 superior fascia of the urogenital diaphragm. The posterior surface 

 is in contact with the rectum and can readily be palpated on rectal 

 examination. The lateral surface is crossed by the anterior border 

 of the levator ani and can also be examined from the rectum. 



The prostate encloses the first part of the urethra, which 



