480 



THE MUSCULAR SYSTEM. 



Its lower fibres, arching over the spermatic funiculus, assist in forming, laterally, 

 the anterior wall of the inguinal canal ; medially, by means of the falx inguinalis, 

 it helps to form the posterior wall of the canal. 



Its lowest fibres are continued into the cremaster muscle, which is prolonged 

 along the spermatic cord through the inguinal canal. 



M. Cremaster. The cremaster muscle forms an investment for the testis and sper- 

 matic funiculus deep to the external spermatic fascia. In the female it is more largely 

 represented by fascia than muscular fibres, and constitutes the cremasteric fascia. It 

 may be said to have an origin from the inferior edge of the obliquus internus and the 



Aponeurosis of 



obliquus externus 



(reflected) 



Linea alba 



Subcutaneous 



inguinal ring 



Lig. reflexum inguinale 



Inferior crus of 



ring 



Pubic fascia and 

 suspensory liga- 

 ment of penis 



OBLIQUUS EXTERNUS 

 ABDOMINIS 



Anterior superior 

 "iliac spine 



OBLIQUUS INTERNUS 

 ABDOMINIS 



Aponeurosis of 

 .obliquus externus 

 (reflected) 



Spermatic funiculus 



-Inguinal canal 

 .Falx aponeurotica 

 inguinalis 



Lig. reflexum iiiguinale 

 Inferior crus of sub- 

 cutaneous inguinal ring 

 (the inguinal ligament) 



Spermatic funiculus 

 (cut) 



FIG. 426. THE LEFT INGUINAL CANAL. STKTJCTTJRES SEEN ON REFLECTION OF THE OBLIQUUS EXTERNUS. 



adjacent part of the inguinal ligament. Its fibres form loops over the spermatic funiculus 

 and testis, the highest fibres getting an insertion into the pubic tubercle. 



M. Transversus Abdominis. The transversus abdominis muscle arises (1) 

 from the deep surface of the costal cartilages of the lower six ribs, interdigitating 

 with the origins of the diaphragm ; (2) from the lumbo-dorsal fascia ; (3) from the 

 anterior half of the medial lip of the iliac crest ; and (4) from the lateral third 

 of the inguinal ligament.' 



The muscular fibres run, for the most part, horizontally forwards, and end 

 in an aponeurosis which has a twofold insertion. (1) After forming (along 

 with the aponeurosis of the obliquus internus) the posterior layer of the sheath oi 

 the rectus, the aponeurosis is attached to the xiphoid process and linea alba 

 (2) The inferior fibres of the muscle arising from the inguinal ligament are joinec 

 by the inferior part of the obliquus internus to form the larger part of the fab 



