MYOLOGY. 65 



ABDOMINAL REGION. 



EXTERNAL OBLIQUE. 



Origin. — External surface of thirteen or fourteen lower ribs 

 and aponeurosis of latissimus dorsi. 



Insei'tion. — Into linea alba and pre-pubic tendon. A number 

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

 erior spine of the ilium, forming Pouparfs 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. 



Actiofi. — 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. 



TRANSVERSALIS. 



Origin. — Internal surface of asternal ribs, and transverse pro- 

 cesses of lumbar vertebrae. 



Insertion. — Into linea alba (or middle aponeurosis of abdo- 

 minal 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. 



