i MUSCLES OF THE PELVIS. 411 
The levator ani arises from (1) the back of the body of the pubis, (2) the 
parietal pelvic fascia above or along the white line, and (3) the spine of the ischium. 
Its fibres are directed downwards and backwards, to be inserted into (1) the central 
point of the perineum, (2) the external sphincter around the anus and the ano- 
coceygeal raphe behind the anus, and (3) into the sides of the lower sacral and the 
coccygeal vertebree. 
The concave upper surface of the muscle is covered in part by the visceral 
Sacro-sciatic 
ye Se (cut) 
Y ry 
Pelvic 
peritoneum ——~_ 
IScHIO-coccy- 
— GEus (part of 
Extra- i 
peritoneal 2 
te a: levator ani) 
tissue 
The white 
line of the SE ; 1 
pelvic fascia ] ~——1_Ischial spine 
Pubie bone (cut) 
(cut) 
~~ ———_| IscuIo- ) 
COCCYGEUS 
IscHio- 
CAVERNOSUS 
I 
COCCYGEUS 
/ 
BULBO-) + 
- F 
CAVERNOSUS j 
Parts of levator ani 
T7—~__PUBO- 
CoccyGEUsS / 
Transversus perinei 
SPHINCTER ANI 
Posterior layer of EXTERNUS 
triangular ligament 
COMPRESSOR URETHR& 
Triangular ligament 
Fic. 306.—THE FascraL AND MuscuLaR WALL OF THE PELVIS AFTER RNMOVAL OF PART OF THE LEFT 
INNOMINATE BONE. 
pelvic fascia; in part it is in contact with the rectum behind and the prostate 
gland or vagina in front. The inferior convex surface of the muscle forms the 
inner wall of the ischio-rectal fossa. Its posterior edge is overlapped by the 
ischio-coccygeus; its anterior edge is in contact with the posterior layer of the 
triangular ligament. 
The levator ani is divisible into four parts—pubo-rectalis, pubo-coccygeus, ilio- 
coccygeus, and ilio-sacralis. The pubo-rectalis (levator prostate.) is the part inserted into 
the central point of the perineum. The pubo-coceygeus is the part inserted into the anus 
and the ano-coccygeal raphe, and the ilio-coccygeus and ilio-sacralis are represented by 
the fibres attached to the sacrum and coccyx. The first two are best developed ; the last 
two series of fibres the most rudimentary. These several parts of the muscle represent 
the remains of the flexor caudie of tailed animals. 
