406 THE MUSCULAR SYSTEM, ea 
median raphe continuous further forwards with the septum of the scrotum 
mentioned above. Anteriorly the fascia is continued over the spermatic cords to 
the anterior abdominal wall. The importance of this fascia hes in relation to the 
extravasation of urine from a rupture of the urethra. By the fascial attachments 
the fluid is prevented from passing backwards into the ischio-rectal fossa, or 
laterally into the thigh. It is directed forwards into relation with the scrotwm 
and penis, and along the spermatic cord to the anterior abdominal wall. The 
septum of the scrotum being incomplete, fluid extravasated on one side can pass 
across the middle line to the opposite half of the perineum and scrotum. 
The deep fascia of the perineum is practically non-existent, except in the 
form of delicate aponeuroses of the muscles. 
THE MUSCLES OF THE PERINEUM. 
The perineal muscles are naturally separated into a superficial and a deep set by 
the triangular ligament. Superficially are the sphincter ani externus, transversus 
perinei superficialis, bulbo-cavernosus, and ischio-cavernosus ; beneath the triangular 
ligament is the compressor urethree. 
Sphincter ani Externus.—This muscle is fusiform in outline, flattened, and 
obliquely placed around the anus and anal canal. It can be separated into three 
BULBO-CAVERNOSUS 
ra 
Perineal branch of small 
sciatic ~_ ~ ERECTOR PENIS 
Anterior TRANSVERSUS 
superficial an ae 
; PERINEL 
perineal = ——____ | 
nerve K ‘ 
<\— schial tuberosity Ss 
Posterior ' 
superficial : 
perineal ] LEVATOR ANI 
nerve y 
Gluteal \ f 
branches, 
small sciatic 
nerve GLUTEUS 
MAXIMUS 
Parietal pelvic , 
fascia 
Inferior hemorrhoidal nerve S S = > LEVATOR ANI 
Perforating cutaneous nerve EXTERNAL SPHINCTER ANI 
Perineal branch, fourth sacral nerve Anterior sacro-coccygeal nerve R 
7 
Fic. 300.—THE MuscLtes AND NERVES OF THE MALE PERINEUM. 
layers: viz. subcutaneous, superficial, and deep. (1) The most superficial lamina 
consists of subcutaneous fibres decussating behind and in front of the anus, but — 
without bony attachments. (2) The sphincter ani superficialis constitutes the — 
main portion of the muscle. It is attached posteriorly to the coccyx, and in 
front of the anus reaches the central point of the perineum. (3) The deep fibres 
of the muscle form for the most part a complete sphincter for the anal canal. They 
are continuous with the fibres of the levator ani; they encircle the anal canal, and 
blend anteriorly with the central point of the perineum and the transversus 
perinei. 
The muscle surrounds the anus, covered only by the skin, superficial fascia, and 
