Ii68 A MANUAL OF ANATOMY 



Insertion. — ^The skin over the back part of the ala of the nose. 



Nerve-supply. — ^The facial nerve. 



Action. — ^To dilate the nostril. 



Levator Labii Superioris — Origin. — ^The superior maxilla between 

 the infra-orbital foramen and the lower margin of the orbit. 



Insertion. — ^The skin of the upper lip. 



Nerve-siipply. — ^The facial nerve. 



Action. — To raise the upper lip. 



The muscle is quadrilateral. At its origin it is overlapped by 

 the lower half of the orbicularis palpebrarum, and it covers the 

 infra-orbital nerve and artery as they emerge from the infra-orbital 

 foramen. At its insertion the fibres interlace with those of the 

 upper half of the orbicularis oris. Its inner border is joined by 

 some of the fibres of the outer or labial slip of the levator labii 

 superioris alaeque nasi, and its outer border is joined by some fibres 

 of the zygomaticus minor. 



Levator Anguli Oris — Origin. — ^The upper part of the canine fossa 

 of the superior maxilla, under cover of the levator labii superioris. 



Insertion. — ^The angle of the mouth, where some of the fibres are 

 inserted into the skin, whilst others decussate with those of the 

 depressor anguli oris, and enter the lower lip, mingling with those 

 of the lower half of the orbicularis oris. 



Nerve-supply. — ^The facial nerve. 



The direction of the muscle is downwards and slightly outwards. 



Action. — To raise the angle of the mouth, and at the same time 

 to draw it slightly inwards. 



The infra-orbital nerve and artery are superficial to the muscle. 



Zygomaticus Minor — Origin. — ^The anterior and lower part of the 

 malar bone, close to the superior maxilla. 



Insertion. — ^The skin of the upper lip immediately external to 

 the levator labii superioris, with the outer border of which muscle 

 some of its fibres blend. 



Nerve-supply. — ^The facial nerve. 



The muscle is directed downwards and inwards. 



Action. — ^To raise feebly the upper lip, and at the same time to 

 draw it slightly outwards. 



Zygomaticus Major — Origin. — ^The outer surface of the malar 

 bone near the zygomatic suture. 



Insertion. — ^The skin at the angle of the mouth, where its fibres 

 blend with those of the orbicularis oris. 



Nerve-supply. — ^The facial nerve. 



The muscle is directed downwards and inwards. 



Action. — ^To draw the angle of the mouth upwards and out- 

 wards. 



Risorius of Santorini — Origin.— ^h.e deep fascia which covers the 

 masseter muscle and parotid gland. 



Insertion. — ^The skin at the angle of the mouth, where its fibres 

 blend with the orbicularis oris. 



Nerve-supply. — The facial nerve. 



