406 ABDOMEN 



These are the two terminal branches of the internal mam- 

 mary. The superior epigastric will be found behind the rectus 

 muscle and within the upper part of its sheath. It gives 

 twigs to the rectus, and anastomoses with the inferior epi- 

 gastric and the intercostal arteries. 



The musculo-phrenic can only be seen by reflecting the 

 transversus abdominis from the ribs. It will be found at the 

 level of the eighth rib. From this it proceeds downwards 

 along the attachment of the diaphragm, to the last intercostal 

 space. It gives branches to the diaphragm and others 

 (anterior intercostalis), which enter some of the lower inter- 

 costal spaces. 



Dissection. When the transversalis fascia is reflected the only layers 

 which intervene between the dissector and the abdominal cavity are the 

 extra-peritoneal fatty tissue and the parietal peritoneum. 



If the subject be a male, now is the best time for the student to examine 

 the constitution of the scrotum, spermatic cord, and testis. This can 

 only be done at present on the right side, as the parts on the opposite side 

 must be kept in sitii for the study of hernia. After that study has been 

 made the dissection can be repeated on the left side. 



Scrotum. This is a pendulous purse-like arrangement of 

 the skin and superficial fascia for the lodgment of the testes. 

 The skin composing it is of a dark colour and rugose, and is 

 traversed, along the middle line, by a median raphe or ridge, 

 an indication of its bilateral character. 



The superficial fascia possesses certain characters peculiar to 

 itself. It has a ruddy colour, and is totally devoid of fat. 

 The ruddy tint is due to the presence of involuntary muscular 

 fibres, which take the place of the fat and constitute what 

 is called the dartos muscle. The rugosity of the scrotal skin 

 is maintained by these muscular fibres. But, further, the 

 superficial fascia forms an imperfect septum or partition, 

 which divides the interior of the scrotum into two chambers 

 one for each testis. These points in connection with the 

 construction of the scrotum have all, to a certain degree, 

 been noted in the dissection of the perineum. 



But these two scrotal tunics are not the only coverings of 

 the testis. Each constituent of the abdominal wall has 

 been seen to contribute an investment to the spermatic cord, 

 and these in turn are continued down so as to clothe the 

 testis. Presuming, then, that the skin and superficial fascia 

 are reflected, the testis and cord within the scrotum will 

 still be found to be invested by 



