MYOLOGY. 65 



ABDOMINAL REGION. 



EXTERNAL OBLIQUE. 



Origin. External surface of thirteen or fourteen lower ribs 

 and aponeurosis of latissimus dorsi. 



Insertion. Into linea alba and pre-pubic tendon. A number 

 of strong fibres are reflected from the pubes to the anterior su- 

 perior spine of the ilium, forming Poupart's ligament. 



Action. Compresses abdominal viscera, flexes spine and acts 

 as muscle of forced expiration. 



Nerve. Intercostal and lumbar. 



INTERNAL OBLIQUE. 



Origin. Aponeurosis of latissimus dorsi; external angle of 

 ilium; outer fourth of Poupart's ligament, and external face of 

 last few ribs. 



Insertion. Linea alba; the fibres separating inferiorly to form 

 part of the inguinal canal. 



Action. Same as preceding. 



Nerve. Intercostal and lumbar. 



RETRACTOR OF LAST RIB. 



Origin. From transverse processes of first two or three lum- 

 bar vertebrae. 



Insertion. Posterior border of last rib. 

 Action. Fixes last rib. 

 Nerve. Lumbar. 



TRANS VERSALIS . 



Origin. Internal surface of asternal ribs, and transverse proc- 

 esses of lumbar vertebras. 



Insertion. Into linea alba (or middle aponeurosis of abdom- 

 inal tunic) and crural arch. 



Action. Same as oblique muscles. 



Nerve. Intercostal and lumbar. 



RECTUS ABDOMINIS. 



Origin. To cartilages of fifth, sixth, seventh, eighth, and ninth 

 ribs, and inferior face of sternum. 



Insertion. To common tendon into pubes. 



