432 THE MUSCLES 



3. RETRAHENS AUREM 



The retrahens aurem — named from its aetion of drawing back the auricle — 

 consists of two nuiscular l)ands, wliich narrow shghtly as they pass forwards to the 

 ear. 



Origin. — Tlie upper part of the outer surface of the mastoid process of the 

 temporal bone. 



Insertion. — The inner surface of the concha. 



Structure. — It consists usually of darker and more distinctly fleshy bands 

 than the two preceding muscles. They arise, one alcove the other, by short tendi- 

 nous fibres from the mastoid process, and pass transversely forwards to their tendi- 

 nous insertion. 



Nerve -supply. — The posterior auricular Ijranch of the facial, which sends 

 filaments to the lower part of its deep surface. 



Action. — To draw l^ack the auricle. 



Relations. — Superficially, the skin; deeply, the posterior auricular artery, part 

 of the great auricular and the posterior auricular nerves. 



THE MUSCLES OF THE NOSE 



The chief muscles of the nose are three in number: viz. the pyramidalis nasi 

 and compressor narium, which consist of muscular fibres which pass up^vards and 

 outwards from an aponeurosis, covering the cartilaginous part of the ridge of the 

 nose, and intimately connected with the under surface of the skin; and the depressor 

 alse nasi. A small slij) from the levator labii superioris alseque nasi is also attached 

 to the ala nasi; and two little muscles may sometimes be found in the subcutaneous 

 tissue upon the outer surface of the nostril: viz. the dilatator naris anterior and 

 posterior. 



1. PYRAMIDALIS 



The pyramidalis (figs. 309 and 311) — named from its triangular shape, Avhich is 

 like the side of a pyramid — is a thin sheet. 



Origin, — The upper border of the nasal aponeurosis over the junction of the 

 cartilage with the lower border of the nasal bone. 



Insertion. — The deep surface of the skin lietween the eyebrows, being at this 

 point cuntiiuious with the inner fibres of the frontalis. 



Structure. — The muscular fibres form a slightly curved sheet, Avhich wraps 

 round the anterior surface of the nasal bone, and is continuous with the correspond- 

 ing muscle of the other side. They converge as they pass upwards, and the outer 

 ones run slightly inwards as well as upwards, to their insertion. 



Nerve-supply. — The infraorbital branch of the uppc^r division of the facial, 

 which enters the outer part of its deep surface. 



Action. — To draw downwards the skin between the eyebrows, so as to throw it 

 forwards into a fold, and at the same time to produce a transverse groove above 

 the bridge of the nose. This gives to the face a stern, aggressive, or fierce 

 expression. 



Relations. — Sujicrticially, the skin; and deeply, the nasal bone. 



Variation. — Tills muscle is sometimes absent. 



2. COMPRESSOR NARIUM 



The compressor narium (figs. 309 and 311) — named from its supposed action 

 as a compressor of the nostrils — is a triangular sheet, the base of which is attached 

 to the nasal aponeurosis above mentioned. 



