Ii66 A MANUAL OF ANATOMY 



Action. — ^To draw backwards the outer part of the internal tarsal 

 ligament, and in this manner compress the lachrymal sac, the 

 effect of which is to propel the tears into the nasal duct. 



Corrugator Supercilii — Origin. — ^The inner extremity of the super- 

 ciliary ridge of the frontal bone. 



Insertion. — ^The deep surface of the skin of the eyebrow at the 

 centre. 



Nerve-supply. — The facial nerve. 



The direction of the muscle is outwards and upwards, and to 

 reach the skin the fibres pass through the upper part of the orbicu- 

 laris palpebrarum and the adjacent portion of the frontalis. 



Action. — ^To draw the skin of the eyebrow inwards and down- 

 wards, giving rise to verffccal wrinkles between the eyebrows, as in 

 frowning. 



The muscle is under cover of the inner portion of the upper half 

 of the orbicularis palpebrarum, and it conceals the supratrochlear 

 nerve as it emerges from the orbit. 



Muscles of the Nose — Pyramidalis Nasi — Origin.— The aponeurosis 

 of the compressor naris over the lower part of the nasal bone. 



Insertion. — ^The deep surface of the skin over the glabella of the 

 frontal bone. Some of the fibres become continuous with the 

 mesial portion of the frontalis. 



Nerve-supply. — ^The facial nerve. 



Action. — ^To draw downwards the skin between the eyebrows, 

 giving rise to transverse wrinkles. 



Compressor Naris — Origin. — ^The superior maxilla between the 

 canine fossa and the nasal notch. 



Insertion. — By means of an expanded aponeurosis which blends 

 with its fellow of the opposite side over the cartilaginous portion 

 of the nose, and gives origin superiorly to the pyramidalis nasi. 



Nerve- supply. —The facial nerve. 



Action. — ^To depress the cartilaginous portion of the nose. 



The muscle is triangular, and at its origin is under cover of 

 the levator labii superioris alaeque nasi. 



Levator Labii Superioris Alaeque Nasi — Origin. — The outer 

 surface ol the nasal process of the superior maxilla by a pointed 

 extremity. 



Insertion. — By means of two slips. The inner or nasal slip is 

 inserted into the skin of the ala of the nose. The outer or labial 

 slip is inserted into the skin of the upper lip, some of its fibres 

 blending with the levator labii superioris, and others with the 

 upper part of the orbicularis oris. 



Ne/ve- supply. — ^The facial nerve. 



Action. — (i) To raise the upper lip, and (2) to raise, and dilate, 

 the ala of the nose. 



The muscle is triangular, and covers the origin of the compressor 

 naris. 



Depressor Alae Nasi — Origin. — ^The incisor fossa of the superior 

 maxilla. 



