ABDOMINAL MUSCLES. 335 



anterior part of the sheath, but very slightly to the posterior 

 layer.* 



Use. To compress the forepart, but more particularly the 

 lower part of the belly ; to bend the trunk forwards, or to raise 

 the pelvis. By its tendinous intersection, it is enabled to con- 

 tract at any of the intermediate spaces ; and, by its connexion 

 with the tendons of the other muscles, it is prevented from 

 changing place, and from rising into a prominent form when 

 in action. 



The short muscle in the middle is named 



Pyramidatis, 



Arises along with the rectus ; and running upwards within 

 the same sheath, is 



Inserted, by an acute termination, near half way between 

 the os pubis and umbilicus, into the linea alba and inner edge 

 of the rectus muscle. 



As it is frequently wanting in both sides without any incon- 

 venience, its 



Use seems to be, to assist the inferior part of the rectus. 



Muscles about the male Organs of Generation. 



The testicles are said to have a thin muscle common to both, 

 and one proper to each. 



The common muscle is called the 



Dartos. 



This consists of muscular fibres blended with the cellular 

 membrane lining the scrotum ; and therefore this portion of 



* To obtain an accurate idea of the arrangement of the tendons of the three 

 large pair of abdominal muscles, it will be necessary to raise or separate the 

 external oblique muscle and tendon from the internal oblique and its tendon, as 

 far as the linea semilunaris, and to separate the internal oblique in the same 

 manner from the transversalis ; and then to make an incision in the tendon of 

 the external oblique parallel to the linea alba, and about an inch and a half 

 from it, so as to bring the whole of the rectus muscle into view. The structure 

 of the sheath which contains the rectus can then be examined. 



