232 PRACTICAL ANATOMY. 



conjoined tendon into the pubic crest and ilio-pectineal line for a variable dis- 

 tance. 



The transversalis muscle is now fully exposed to view. (Fig. 162.) On 

 its outer surface you see the plexus of nerves and the vessels previously described. 

 Or. its inner surface you will find the transversalis fascia. The fibres of this 

 muscle extend transversely across the wall. The muscle arises (i) from the 

 inner surfaces of the six lower ribs, interdigitating with the diaphragm ; (2) from 

 the lumbar fascia ; (3) from the inner lip of the iliac crest ; (4) from the outer 

 two-thirds of Poupart's ligament. The muscle is inserted into (i) the linea alba ; 

 (2) the crest of the pubes ; (3) the ilio-pectineal line. This muscle assists the 

 internal oblique in forming the arch and the conjoined tendon. 



FIG. 163. INTERNAL OBLIQUE AND TRANSVERSALIS ABDOMINIS MUSCLES. 



I. Reclus abdominis. 2, 2. Internal oblique. 3, 3. Anterior leaflet of aponeurosis of interim! oblique. 

 4, 4. Divided external oblique. 5, 5. Spermatic cords. 6, 6. Inferior portion of aponeurosis of 

 external oblique. 7. Lower portion of left rectus abdominis; upper portion removed. 8, 8. Mus- 

 cular portion of transversalis abdominis. 9. Aponeurotic portion. 10. Umbilicus. II. Supra 

 umbilical portion of linea alba. 12. Infra-umbilical portion. 13. Serratus magnus. 14. Divided 

 right latissimus dorsi. 15. Divided left latissimus dorsi. 16 Divided serratus magnus. 17, 17. 

 External intercostals. 18, 18. Femoral aponeurosis. 19. Divided internal oblique. 



The Rectus and Pyramidalis. Make an incision through the sheath of 

 the rectus, extending from the pubic spine to the fifth rib, parallel with the linea 

 alba. Carefully dissect the sheath both ways /. e., turn the sheath to the right 

 and left until you have fully exposed the muscular contents. (Fig. 160.) The 

 white lines crossing the rectus are the linea? transversa;. You will find the pyra- 

 midalis below, arising from the pubic crest in front of the rectus. Trace it to its 

 insertion into the linea alba. (Fig. 160.) Now you can easily lift the rectus from 

 its bed, and look down on the posterior part of its sheath. (Fig. 163.) A descrip- 

 tion of the formation of the sheath is given in the beginning of this section. Cut 

 through the rectus one inch below the umbilicus and see : (i) The deep epigastric 

 artery and its veins ; (2) the sciiiilunar fold of Douglas. Turn the divided ends 

 of the rectus aside and trace out the branches of the deep epigastric artery. 



