When the rest of the orbicularis is fixed, this portion will draw the columna and the apex of the nose backwards and downwards; and when the rest of the orbicularis is relaxed, it will draw the middle of the upper lip upwards.
6. I have mentioned a layer of pale mus cular fibres arranged in various directions under the skin of the lower part of the ala nasi, among which fibres of the compressor, de pressor, and levator a.1 nasi appear to mingle. It is by these fibres that the dilatation of the nostril is cominonly effected ; for, as any one may feel and see in his own person, this act is ' not usually performed by any of the muscles yet described, but by fibres which are situated below the triangularis and entirely within the moveable part of the ala. In most instances, no definite arrangement of these fibres can be perceived ; yet they certainly sometimes form distinct fasciculi, which may be described as separate muscles. Arnold makes from them two muscles: 1. Compressor narium minor, (g,.fig. 403), a small triangular muscle pass ing from the skin of the tip of the nose back 1 wards and a little upwards, with its fibres diverging, to the anterior part of the inferior cartilage. Theile has never seen this muscle ; in one very muscular subject I found a dis tinct trace of it; and it nearly corresponds to . that which Santorini has drawn, (tab. i. e, e) ' and which lie says he once saw in action du . ring dyspncea in a woman. Ile regarded it as a dilator of the anterior part of the pinna; Arnold considers it a compressor ; the former opinion is the more probable. 2. Arnold has figured a larger quadrilateral muscle le vator aid nasi proprins (h, fig. 403), which is nearly the same as Theile's dilatator narium anterior. Theile describes it as arising from the upper edge and miter surface of the inferior cartilage, its origin extending from within two lines of' the dorsum of the nose to the sesa mold cartilages. Hence its fibres proceed downwards and are lost in the skin on the I anterior part of the edge of the nostril. Its , I ' action is to draw the anterior part of the ala outwards, and thus to dilate the nostril. Theile also describes a dilatator narium posterior, which may be found by removing all the fibres of the common levator, the depressor nasi and the triangularis. A mass of cel
lular tissue is thus exposed on the inferior and posterior part of the ala, in which muscular fibres may always be seen with the microscope, if not with the naked eye. They arise tendi nous from the edge of the ascending procbs of the superior maxillary bone and from the'sesa mold cartilages, and thence descending arelost_ in the skin of the posterior half of the edge of the nostril. Their action is to draw the poste rior part of the ala outwards, and thus to dilate the nostril.
7. One more muscle may be mentioned, though it is only indirectly connected with the nose. It is that named rhomboidens by San torini (tab. i.f), and anomalus by Albinus, from its being fixed at both its ends to immovable points. Its origin is confounded with that of the triangularis at the upper and outer part of the canine fossa; whence its fibres proceed in a broad fasciculus upwards and inwards in the fossa by the side of the nose to be attached to the surface of the superior maxillary bone close to the outer origin of the levator communis. The strength of the fibres of this singular mus cle indicates that they must act frequently; but the only effect which their contraction can be supposed to have is that of tightening and drawing in the tissues over them with which they are pretty closely connected.
The purposes served by the muscles Of the nose are but few. Their action contributes little to the various expressions' of the con dition of the mind. The sneer of conternpt is perhaps the only expression in which they take a chief part. In extreme fear they appear also to be all contracted; but in this they are affected in common with the other muscles of the face, which all seem to be seized by a tem porary spasm. Their other acts have reference to respiration, and are observed in their ex treme degrees, in the dilatatiofi of the nostrils to permit the freer ingress of the air in dys pm:ea, and in their contraction in the endea vour to perceive a slight odour, by drawing the air quickly upwards towards the seat of the most numerous filaments of the olfactory nerve.