284 THE MUSCLES OF THE HEAD AND NECK. 



The compressor naris, a thin triangular muscle, arises narrow and fleshy from 

 the facial surface of the superior maxillary bone by the side of the anterior nasal 

 aperture ; proceeding forwards and inwards, it gradually expands into a thin 

 aponeurosis, which is blended with that of the corresponding muscle of the opposite 

 side, and with the pyramidalis nasi above, being closely attached to the skin of the 

 nose, but only connected by loose areolar tissue to the subjacent cartilages. It is- 

 concealed at its origin by the muscle next described. 



The levator labii superioris alaeque nasi, the common elevator of the lip 

 and nose, lies along the side of the nose, extending from the inner margin of the 

 orbit to the upper lip. It arises by a pointed process from the nasal process of the 

 superior maxillary bone, and, as it descends, separates into two fasciculi ; one of 

 these, much the smaller, is inserted into the wing of the nose, while the other is 

 prolonged to the upper lip, where it is attached to the skin and becomes blended 

 with the orbicularis and the special elevator muscle. It is subcutaneous, except at 

 its origin, where the orbicularis palpebrarum overlaps it a little. 



Fig. 268. MUSCLES OP THE SIDE OF THE NOSE AND UPPER LIP. 

 (Allen Thomson, after Arnold.) f 



1, pyramidalis nasi ; 2, levator labii superioris alaeque nasi ; 3, com- 

 pressor naris ; 4, levator proprius aloe nasi anterior ; 5, levator proprius 

 alre nasi posterior ; 6, depressor alse nasi ; 7. septal origin of orbicularis 

 oris. 



The depressor alae nasi is a small flat muscle which 

 arises from the incisor fossa of the superior maxilla, and is 

 inserted into the septum and posterior part of the ala of the 

 nose. Some fibres are continued from the outer part of this 

 muscle into the compressor naris. 



Besides the muscles above described there are other irre- 

 gular and often indistinct fibres which enlarge the orifice of 

 the nose. Of these the following may be distinguished. 



The levator proprius alae nasi posterior, or dila- 

 tator naris posterior, is attached to the lateral margin of the nasal aperture 

 and the smaller (quadrate) cartilages of the nose on the one hand, and to the skin 

 on the other. Another set of fibres, the levator proprius alae nasi anterior, or 

 dilatator naris anterior, runs from the cartilage of the aperture of the nose to 

 the skin at the margin of the nostril. The fibres of both of these muscles are very 

 pale and often indistinct. 



Varieties. Absence of the pyramidalis has been observed. The compressor naris is some- 

 times very slightly developed, or even reduced to an aponeurotic condition. The dilators and 

 depressor of the nostril are also subject to considerable variations in strength and in the mode 

 of their attachment. The musculus anomalus of Albinus is a longitudinal muscular slip 

 frequently present, lying beneath the common elevator of the lip and nose. It springs with 

 the latter muscle from the nasal process of the superior maxilla, and ends below on the same 

 bone in connection with the origin of the compressor naris. 



Actions. Ihepyramiddlis nasi muscle takes its fixed point from below and draws down 

 the integument of the forehead, producing wrinkles across the root of the nose. The 

 roni2>rcxsor naris, acting along with its fellow of the other side, depresses the cartilaginous 

 part of the nose, and to some extent also compresses the alse together. The actions of the 

 other muscles are sufficiently indicated by their names ; the dilatation of the alas is seldom 

 perceptible in natural inspiration, but is well-marked in dyspnoea. 



