THE SCEOTUM. . 441 



wall. It extends from the deep to the superficial abdominal ring, and 

 is about an inch and a half in length. In the upper part of this course, 

 the cord has placed behind it the fascia transversalis, and is covered in 

 fi'ont by the lower fibres of the internal oblique and transversalis 

 muscles ; lower down it lies in front of the conjoined tendon of these 

 muscles, the fibres of which have arched inwards over it, and its cre- 

 masteric covering is in contact anteriorly with the aponeurosis of the 

 external oblique muscle. The inguinal canal is therefore said to be 

 bounded posteriorly by the fascia transversalis above and the conjoined 

 tendon below, and anteriorly by fibres of the transversalis and internal 

 oblique muscles above, and the aponeurosis of the external oblique 

 muscle below ; Avhile its floor is formed by the curving backwards of 

 Poupart's ligament, and its roof by the apposition of the layers of 

 t!ie abdominal wall and the arched fi-bres of the internal oblique 

 muscle. 



As it enters the inguinal canal, the cord receives a covering from 

 the infundibuliforni fascia, a thin laj^er continuous with the fascia 

 transversalis, and prolonged down from the margin of the deep abdo- 

 minal ring ; within the canal it receives a covering from the cremaster 

 muscle and its layer of fascia; and as it emerges from the canal 

 there is added, superficially to tliis, the intercolumnar fascia prolonged 

 from the margin of the superficial abdominal ring. 



The SCEOTUM. — The scrotum forms a purse-like investment for the 

 testes and part of the spermatic cords. Its condition is liable to 

 some variations according to the state of the health and other cir- 

 cumstances : thus it is short and corrugated in robust persons and 

 mider the efi'ects of cold, but becomes loose and pendulous in persons 

 of weak constitution, and under the relaxing influence of heat. A 

 superficial division into two lateral halves is marked by a slight median 

 ridge, named the raphe, extending forwards to the under side of the 

 penis, and backwards along the perinfeum to the margin of the anus. 



The coverings of the cord and testis in the scrotum may be enume- 

 rated from without inwards as follows, viz., the slcin, siq^crficial fascia 

 and dartos tissue, the intercolumnar fascia, the cremaster muscle and 

 fascia, and the infumlihuliform fascia, which is united to the cord by a 

 layer of loose areolar tissue ; lastly, the special serous membrane of 

 the testicle, named the tunica vaginalis, which forms a close sac, of 

 which one part lines the scrotum and the other closely envelopes the 

 testicle. 



1. The sHn of the scrotum is very thin, and is of a darker colour 

 than elsewhere ; it is generally thrown into rugae or folds, which are 

 more or less distinct according to the circumstances already mentioned. 

 It is furnished with sebaceous follicles, the secretion from which has a 

 peculiar odour, and it is covered over with thinly scattered crisp and 

 flattened hairs, the bulbs of which may be seen or felt through the skin 

 when the scrotum is stretched. The superficial blood-vessels are also 

 readily distinguished through this thin integument. 



2. Immediately beneath the skin of the scrotum there is found a 

 thin layer of a peculiar loose reddish-brown tissue, endowed with con- 

 tractility, and named the dartos tunic. This subcutaneous layer is 

 continuous with the superficial fascia of the groin, perinreum, and inner 

 side of the thighs, but assumes a difierent structure, and is entirely 

 free from fat. The dartoid tissue is more abundant on the fore part 



