Muscles Of The Nose
Figure 579
The Procerus is a small pyramidal slip continuous with the medial part of the Frontal belly of the Occipitofrontalis. It arises from the fascia covering the lower part of the nasal bone and the upper part of the upper nasal cartilage; it is inserted into the slain over the lower part of the forehead between the two eyebrows.
Nerve-supply.-The Procerus is supplied by the upper buccal branches of the facial nerve.
Actions.----The Procerus draws down the medial angle of the eyebrow and produces the transverse wrinkles over the bridge of the nose.
The Compressor naris (Nasalis, pars transverse) arises from the maxilla, above and lateral to the incisor teeth; its fibers proceed upwards and medially and expand into a thin aponeurosis, which is continuous on the bridge of the nose with that of the muscle of the opposite side, and with the aponeurosis of the Procerus.
Nerve-supply. -The Compressor naris is supplied by the upper buccal branches of the facial nerve.
Actions.-The Compressor naris compresses the nasal aperture at the junction of the vestibule with the nasal cavity.
The Dilator naris (Nasalis, pars alaris) arises from the maxilla below and medial to the origin of the Compressor naris, and is inserted into the ala nasi. Nerve supply -The Dilator naris is supplied by the upper buccal branches of the facial nerve.
Actions.-The Dilator naris draws the ala downwards and laterally, and so assists in widening the anterior nasal aperture.
The Depressor septi, which is often regarded as a constituent portion of the Dilator naris, arises from the maxilla above the central incisor tooth; its fibers ascend to be inserted into the septum mobile nasi. It lies between the mucous membrane and muscular structure of the lip.
Nerve-supply - The Depressor septi is supplied by the upper buccal branches of the facial nerve.
Actions - The Depressor septi assists the Dilator naris to widen the nasal aperture.
The Dilatatores naris (B.N.A.) are represented by a few, poorly developed muscular slips which arise from the margin of the anterior bony aperture of the nose and the adjoining nasal cartilages and are inserted into the skirt near the margin of the nostril.
In the B.N.A. the Levator labii superioris aleque nasi, the Levatar labii suporioris and the Zygomaticus minor are grouped together and are termed the angular, infraorbital and zygomatic heads, respectively, of the Quadratus labii superioris.
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