N LSAL MUSCLES. 



165 



Origin. It arises from the surface of the superior maxilla, at 

 its j unction with the malar and lachrymal bones. 



Insertion. The tendon passes to the extremity of the nose, 

 where, joining its fellow, it forms a radiating expansion, becoming 

 lost in the upper lip. 



Action. It elevates and corrugates the upper lip, if acting 

 with its fellow ; if acting alone, it pulls the lip to one side. 



FIG. 70. 



Muscles of the head left lateral view, a, Abdncens ; b c d, Scuto-auricularis 

 externus, inferior, middle, and superior portions ; e, Levator palpebrse superioris 

 esternus ; / /, Orbicularis palpebrarum ; g, Xasalis longus ; h, Depressor labii 

 inferioris ; i, Buccinator; k, Masseter; I, Dilatator naris lateralis ; m, Dilatator 

 naris inferioris ; n, Dilatator naris superioris. 



DILATATOR NAEIS LATEKALIS. 



(Pyramidalis Supermaxillo-nasulis Jlagmts. ) 

 (PL. II. 7. FIG. 70. I.) 



This muscle is situated on the side of the cheek, between the 

 branches of the levator labii superioris, extending horizontally ; it 

 has a flat belly and tendon of origin. 



Attachments. It arises from the anterior extremity of the 

 maxillary spine ; it is inserted to the side of the nostril and the 

 upper lip, blending with the orbicularis oris. 



Action. It dilates the nostril, acting on its external wing. 



