324 MUSCLES AND FASCIAE. 



5. NASAL EEGION. (Fig. 215.) 



Pyramidalis Nasi. 



Levator Labii Superioris Alaeque Nasi. 



Dilatator Naris Posterior 



Dilatator Naris Anterior. 



Compressor Nasi. 



Compressor Narium Minor. 



Depressor Alse Nasi. 



The Pyramidalis Nasi is a small pyramidal slip, prolonged downwards from 

 the Occipito-frontalis upon the side of the nose, where it becomes tendinous 

 and blends with the compressor Nasi. As the two muscles descend, they di- 

 verge, leaving an angular interval between them. 



Relations. By its upper surface, with the skin. By its under surface, with the 

 frontal and nasal bones. 



The Levator Labii Superioris Alaeque Nasi is a thin triangular muscle, placed 

 by the side of the nose, and extending between the inner margin of the orbit 

 and upper lip. It arises by a pointed extremity from the upper part of the 

 nasal process of the superior maxillary bone, and passing obliquely downwards 

 and outwards, divides into two slips, one of which is inserted into the cartilage 

 of the ala of the nose ; the other is prolonged into the upper lip, becoming 

 blended with the Orbicularis and Levator Labii Proprius. 



Relations. In front, with the integument; and with a small part of the 

 Orbicular Palpebrarum above. 



Lying upon the superior maxillary bone, beneath this muscle, is a longitu- 

 dinal muscular fasciculus about an inch in length. It is attached by one end 

 near the origin of the Compressor Nasi, and by the other to the nasal process 

 about an inch above it; it was described by Albinus as the "Musculus Anoma- 

 lus," and by Santorini, as the " Ehomboideus." 



The Dilatator Naris Posterior is a small muscle, which is placed partly be- 

 neath the proper elevator of the nose and lip. It arises from the margin of the 

 nasal notch of the superior maxilla, and from the sesamoid cartilages, and is 

 inserted into the skin near the margin of the nostril. 



The Dilatator Naris Anterior is a thin delicate fasciculus, passing from the 

 cartilage of the ala of the nose to the integument near its margin. This muscle 

 is situated in front of the preceding. 



The Compressor Nasi is a small, thin, triangular muscle, arising by its apex 

 from the superior maxillary bone, above and a little external to the incisive 

 fossa; its fibres proceed upwards and inwards, expanding into a thin aponeu- 

 rosis which is attached to the fibro-cartilage of the nose, and is continuous on 

 the bridge of the nose with that of the muscle of the opposite side, and with 

 the aponeurosis of the Pyramidalis Nasi. 



The Compressor Narium Minor is a small muscle, attached by one end to the 

 alar cartilage, and by the other to the integument at the end of the nose. 



The Depressor Alse Nasi is a short, radiated muscle, arising from the incisive 

 fossa of the superior maxilla ; its fibres ascend to be inserted into the septum, 

 and back part of the ala of the nose. This muscle lies between the mucous 

 membrane and muscular structure of the lip. 



Nerves. All the muscles of this group are supplied by the facial nerve. 



Actions. The Pyramidalis Nasi draws down the inner angle of the eyebrows; 

 by some anatomists it is also considered as an elevator of the ala, and, conse- 

 quently, a dilatator of the nose. The Levator Labii Superioris Alaeque Nasi 

 draws upwards the upper lip and ala of the nose; its most important action is 

 upon the nose, which it dilates to a considerable extent. The action of this 

 muscle produces a marked influence over the countenance, and it is the prin- 

 cipal agent in the expression of contempt. The two Dilatatores Nasi enlarge 



