166 MYOLOGY, 



DILATATOR NARIS TRANSVERSALIS. 

 ( Naso-transversalis. ) 



Situated at the supero-anterior extremity of the nose, in front 

 of the nostrils, it is single, flat, and four-sided, consisting of 

 transverse fibres which cross each other. 



Origin. The nasal peak. 



Insertion. The superior surface of the cartilaginous alse of 

 the nostrils. 



Action. It dilates the nostrils. 



DILATATOR NARIS INFERIORIS. 



(FiG. 70. m.) 

 (Nasalis Brevis Labii Superioris Supermaxillo-nasalis Brevis.) 



Another long, and four-sided muscle, situated at the side of, 

 and a little behind the nostrils. 



Origin. It arises by an aponeurotic origin from the upper 

 free margin of the superior maxilla and premaxilla. 



Insertion. The skin of the false nostril. 



Action. It dilates the nostril. 



DILATATOR NARIS SUPERIORIS. 



(FiG. 70. n.) 



Situated just above the preceding, it is broad and thin, with 

 aponeurotic attachments. 



Origin. From the lateral surface of the free margin of the nasal 

 bone. 



Insertion. The skin of the false nostril. 



Action. To assist the preceding muscle. 



DEPRESSOR LABII SUPERIORIS. 



Situated on the inner surface of the upper lip, covered by 

 mucous membrane, it is thin and fleshy. 



Origin. From the premaxilla at the alveoli, extending from 

 the lateral incisors to the tushes. 



Insertion. The diverging fibres pass obliquely forwards to 

 blend with the upper lip and nasal cartilages. 



