9 2 OUTLINES OF ANATOMY. 



External abdominal ring : 



Inner pillar. External pillar. Intercolumnar fibres. 

 Intercolumnar fascia. 

 Nerve-supply. Action. Relations. Variations. 



Carefully divide the aponeurosis of the external oblique by a transverse incision, from near the anterior 

 superior spine of the ilium to the outer border of the rectus, then downward from that point to the 

 pubis, passing to the inner side of the external abdominal ring in order to preserve it intact ; turn the 

 flap thus formed down and out to Poupart's ligament. Also divide the muscle at its origin and near the 

 crest of the ilium, and turn forward to the point where the aponeurosis blends with that of the internal 

 oblique. The ilio-hypogastric 848 (829) and ilio-inguinal 849 (829) nerves perforate the internal 

 oblique near the crest of the ilium and cross the lower portion of the muscle. 



Obliquus internus abdominis, 431-2. (427-8). Fig. 266; P. 312. (315) 



Origin. Insertion, conjoint tendon. 



Structure, linea semilunaris. 



Nerve-supply. Action. Relations. Variations. 

 Cremaster, 432. (428). Fig. 285 ; P. 365. (364) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. 

 Genital branch of the genito-crural nerve, 849. (829) 



Divide the internal oblique near its origin from the crest of the ilium and at Poupart's ligament, detach 

 from the ribs above, and by a vertical incision, from the lumbar fascia behind ; care must be exercised 

 to divide the internal oblique only. Near the crest of the ilium the branches of the deep circumflex 

 iliac artery lie between the internal oblique and transversalis, and will indicate the depth of the in- 

 cision required to divide the internal oblique. Passing forward upon the transversalis will be seen por- 

 tions of the lower intercostal, ilio-hypogastric, and ilio-inguinal nerves. 



Nerve's : 



Lower intercostal nerves : Branches, 845. (826) 



Last thoracic nerve, 846. (826) 



Ilio-hypogastric nerve, 848. (829) 



Ilio-inguinal nerve, 849. (829) 

 Arteries : 



From the lower intercostal : 



The intercostal portion, 582. (571) 

 Subcostal or twelfth dorsal, 583. (572-3) 



Lumbar arteries, 587-8. (576-7) 



Deep circumflex iliac, muscular branches, 613. (601-2) 

 Veins accompany the arteries. 

 Lymphatics : The deep parietal lymphatics of the anterior and lateral abdominal 



walls, 700. (685) 

 Transversalis abdominis, 433-4-5 ; Fig. 304. (429-30) 



Origin. Insertion. 



Structure ; anterior aponeurosis, posterior aponeurosis or lumbar fascia. 



Nerve-supply. Action. Relations. 

 Sheath of the rectus, front portion of sheath, 435. (430-1) 



Open the sheath of the rectus by a vertical incision in the median line of the sheath, reflect the outer 

 portion of the sheath to the outer border of the muscle and the inner portion toward the linea alba. 

 The pyramidalis and rectus will be exposed. 



Pryamidalis, 426. (422-3) Fig. 266; P. 312. (315) 



Origin. Insertion. Structure. Nerve-supply. Action. Relations. Variations. 

 Rectus abdominis, 426-7-8. (423-4) Fig. 266; P. 312. (315) 



Origin, outer head, inner head. Insertion. Structure, lineae transversae. 



Nerve-supply. Action. Linese transversas. Relations. Variations. 



Divide the rectus transversely near the umbilicus, turn the lower portion down to the origin and the 

 upper portion to the insertion, expose the structures in or under the muscles. In raising the muscle note 

 the anterior cutaneous nerves entering its deep surface. 



Deep epigastric artery, 612-13. (601) 



Branches: Cremasteric. Pubic. Muscular. (Cutaneous.) Terminal. 

 Superior epigastric artery, 550 ; Fig. 344. (540) 



Branches: Muscular. Xiphoid (peritoneal). 



