170 SURGICAL ANATOMY OF 



many lamellae as the skill of the dissector permits of; two 

 of which, however, may be considered as ample for all 

 surgical purposes, the superficial and the deep. These 

 fasciae are continuous, and interlace on either side of the 

 linea alba, which is seen as a well-marked depression, 

 and some of their fibres are attached to it, and in the 

 lower portion of the abdomen pass downwards to the 

 scrotum, strengthening the suspensory ligament of the 

 penis, and giving origin to the dartos (vide Inguinal 

 Region). In the fat existing between these laminae lie 

 numerous cutaneous branches of the superficial epigas- 

 tric and intercostal vessels and nerves. Beneath the 

 deeper layer is the external oblique muscle, the fibres of 

 origin of which interdigitate with those of the serratus 

 magnus and latissimus dorsi, and its aponeurosis passes 

 inwards, to be inserted into the iliac spine, the linea 

 alba, and iliac and pubic crests. The fibres of this 

 muscle are oblique from above down wards. Beneath it 

 lies the internal oblique, separated from it by a thin 

 cellular interval, derived originally from the lumbar 

 aponeurosis, and in which lie filaments of the lower in- 

 tercostal and last dorsal nerves ; its tendon is inserted 

 into the cartilages of the lower ribs, the linea alba, and 

 ilio-pectineal line, inclosing the rectus for its upper two- 

 thirds, and passing in front of it entirely for the remain- 

 ing third. The fibres run in the contrary direction to 

 those of the former muscle. The transversalis is sepa- 

 rated from it by a thin cellular interval, and having its 

 origin from the lower ribs and lumbar aponeurosis is in- 

 serted along the linea alba and by the conjoined tendon, 

 the upper three-fourths passing behind the rectus, and 

 blending with the tendon of the internal oblique, whilst 

 its lower fourth passes in front of it. It is separated 



