OF THE BLADDER AND PROSTATE. 
47 
Diagram 6 represents the manner in which the sphincter and the fourth or central 
layer is formed on the right side of the bladder. 
k n, k n, k n. Terminal expansions or loops formed by the very oblique spiral 
figure-of-eight fibres which spread out on the right side of the bladder 
and form the fourth or circular layer in this situation. Their companion 
loops occur on the left side of the cervix, and contribute to the formation 
of the sphincter in this situation ( m mm, III). 
Diagram 7 . Horizontal section of fundus, cervix, prostate, and urethra of adult male. 
Shows relation of ureters to each other, to fibres of trigone, verumontanum, &c. 
v, z. Ureters continued into each other at a, and connected more or less 
directly with the longitudinal (a 1 ), slightly oblique (cc), oblique (g g), 
and very oblique (k k) fibres of the trigone. Those fibres converge 
towards, and in many instances cross at the verumontanum (s), where 
they terminate. A considerable number, however, are continued down- 
wards on the membranous portion of the urethra (a"). 
m,m'. External half of right and left wall of bladder splitting up ( n,n ') a 
certain proportion of the fibres (pjg') going to the prostate gland (q g ') ; 
the greater number to the urethra (o o'). See diagram 8. 
Diagram 8. Vertical section of neck of bladder, urethra, and prostate (enlarged). 
Shows how the urethra is to be regarded as the proper continuation of the 
bladder in an antero-posterior direction, and how the prostate is formed by 
the splitting up of the four outer tunics of the bladder. 
i'- Longitudinal fibres of first layer splitting up at cervix — a certain number 
(a a 1 ) investing the prostate (q) on its dorsal aspect ; some proceeding to 
the dorsal surface of the urethra ( b V), and some ( c ') to the under or 
ventral surface of the prostate (q 1 ). 
2'. Slightly oblique spiral fibres of second layer splitting up ( d ), and passing 
into the substance of the prostate ( d ' d' d ') and into the second layer of 
the urethra (e e). 
3'. Oblique spiral fibres of third layer splitting up (f) ; some passing through 
the prostate (/'/'), others proceeding to the third layer of the urethra. 
4'. Cut ends of a portion of the very oblique spiral fibres of fourth layer, form- 
ing the so-called circular fibres of the prostate (g g l ), the remainder 
occupying the centre of the walls of the urethra. 
i, a & 3. The three external layers of the bladder and urethra. 
4. The central or circular layer. A portion of each of these layers, as has 
been explained, go to form the prostate. 
5, e, & 7. The three internal layers of the bladder and urethra. These layers 
are peculiar to the urethra, and are quite distinct from the three 
external layers forming the prostate and the outer half of the urethra, 
unless in the region of the verumontanum, where they are more or less 
blended with them. 
