184 MYOLOGY, OR ANATOMY OF MUSCULAR SYSTEM 



the head. The Icvatorcs costamm have but little action on the 

 ribs; are regarded as muscles of forced inspiration. The rectus 

 Jnfrralis bends the head to one side. 



THE FASCLffi AND MUSCLES OF THE ABDOMEN 



i 



The fascia of the abdomen is divided into a superficial, and 

 a deep aponeurosis. The superficial fascia is subdivided into a 

 superficial layer and a deep layer. 



The superficial layer of the superficial fascia (Camper's 

 fascia) is continuous with the fascia over the thorax, back, 

 and thighs, and in the male it passes over the penis and outer 

 surface of the cord to the scrotum, helping to form the dartos; 

 from here it is traced backward as the superficial layer of the 

 superficial fascia of the perineum; in the female it passes to the 

 labia majora. The deep layer of the superficial fascia (Scarpa's 

 fascia) is continued above with the superficial layer of the 

 superficial fascia; it is adherent internally to the linea alba and 

 symphysis pubis; below it forms the suspensory ligament of the 

 penis and laterally passes over Poupart's ligament to blend with 

 the fascia lata of the thigh; at the root of the penis it passes 

 over the latter organ and the scrotum and cord to help form 

 the dartos. At the margin of the dartos it is continuous 

 with the deep layer of the superficial fascia of the perineum 

 (Colics' fascia); in the female it is continuous with the labia 

 majora. 



The deep abdominal fascia covers the aponeurosis of the 

 external oblique muscle, but is so closely adherent that. it. is 

 difficult of demonstration. 



1. M. rcchis abdominis, separated from its fellow by the 

 linea alba. Origin, cartilage of the fifth, sixth, and seventh 

 ribs, and usually bone of the fifth, by three slips, sometimes 

 from the ensiform; insertion, by two tendons, the inner smaller 

 one into the front of the symphysis pubis, crossing its fellow 

 of the opposite side, passing down and out to the adductor 

 fascia, down and in to the fascia of the penis; the buter head 

 into the pubic crest or space in front of it if the pyramidalis 

 is lacking. (Henle considers the insertion as below, as it passes 

 into so much movable fascia.) The fibers are interrupted 

 by zigzag transverse tendinous intersections, linea transversse. 



