670 



MAMMALIAN ANATOMY 



the biceps, the semitendinosus, the semimembranosus, and the ob- 

 turator externus ; to the pubes, the pectineus, the external oblique, 

 the adductor, and the obturator externus : on the internal surface, to 

 the ilium, the erector spinee, the iliacus, and the ilio-caudal ; to the 

 ischium, the levator ani, the crus penis, and the obturator internus ; 

 to the pubes, the pubio-caudal and the obturator internus. 



FIG. 521. 



Forty-four Days after Birth. 



OUTER ASPECT. 



INNER ASPECT. 



SOME STAGES IN THE DEVELOPMENT OP THE 

 INNOMINATE BONE. 



(Natural size.) 



Blood-Supply. The innominate receives its blood-supply from 

 different vessels, principally branches of the external and the internal 

 iliac. The most important, perhaps, of these are the branch from the 

 obturator artery, piercing the external surface of the ilium at its lower 

 part, near the anterior border ; the ischiac branch, supplying the iliac 

 dorsal external surface ; and the branch from the deep femoral, entering 

 the ischium on the external surface below the acetabulum. 



Ossification. The innominate is developed from four primary 

 centres and several secondary centres of ossification. The first centre 

 to appear is that for the ilium ; this is followed by the centre for the 

 ischium and the centre for the pubes. To these are added the centre 



