MUSCULAR COATS. CIRCULAR FIBRES. 



949 



reach the sides of the prostate. At the summit a few are continued along 

 the urachus. The longitudinal fibres, taken together, constitute what has 

 been named the detrusor tirince muscle. 



The so-called circular fibres form a thin and somewhat irregular reticulated 

 layer distributed over the body of the bladder, having various appearances 

 in different bladders. Their course may in general be looked upon as trans- 

 verse, but for the most part throughout the upper two-thirds of the bladder 

 they cross one another in very oblique bands : towards the lower part of the 

 organ they assume a more circular course, and upon the fundus and trigouo 

 form a tolerably regular layer. Close to and around the cervix, in immediate 

 connection with the prostate in the male, they densely encircle the orifice 

 and constitute what has been named the sphincter vesicce, which, however, is 

 not distinct from the other fibres. 



Fig. 666. 



Fig. 666, A. VIEW OF THE MUSCULAR FIBRES OP THE BLADDER FROM BEFOKE (after 

 Pettigrew and from Nature). 



On the right side the superficial fibres are shown ; on the left the deep or circular 

 fibres chiefly are displayed, a, on the right side, the median and most superficial 

 bauds of the longitudinal fibres, iu which a slight decussatiou of fibres is seen indicating 

 Pettigrew's longest figure-8 loops ; a, those diverging somewhat ; a", the lowest, 

 which pass much more obliquely ; the attachment of the longitudinal fibres to the prostate 

 is shown ; on the left side c, the upper, </, the middle, and c", the lowest set of circular or 

 deeper fibres ; at s, the thickest and most transverse sets of these fibres forming the 

 sphincter ; p, half the prostate left on the right side, the left having been removed ; u y the 

 urachus, into which some of the longitudinal fibres are seen prolonged. 



Fig. 666, B. VIEW OF THE MUSCULAR FIBRES OF THE BLADDER FROM BEHIND 

 (after Pettigrew and from Nature). 



On the right side the superficial fibres are displayed ; on the left the deeper fibres of 

 the same kind or intermediate fibres, and some of the circular fibres ; b, b, the median, 

 most superficial and strongest bands of longitudinal fibres on the right side ; b', the 

 more diverging set of fibres near the middle of the bladder ; b", the most divergent 

 fibres which surround the entrance of the ureters ; on the left side, c, c', and c", indicate 

 the deeper circular fibres passing round at various levels and crossing with the deeper 

 diverging fibres posteriorly; s, the most transverse fibres at the neck forming the 

 sphincter ; u, the urachus ; ur, the ureters ; the left half of the prostate has been 

 removed to show the sphincter ; v, part of the right vas deferens and vesicula seminalis. 



