60 A MANUAL OF ANA TO MY. 



Insertion. Into the outer margin of the levator labii su- 

 perioris. 



Nerve Supply. Same as above. 



Action. To raise the outer part of the upper lip. 

 Levator Labii Superioris. 



Origin. From the superior maxillary bone just below 

 the orbit. 



Insertion. Into the orbicularis oris and skin of the 

 upper lip. 



Nerve Supply. Infra-orbital branch of the facial. 



Action. To elevate the upper lip. 

 Levator Labii Superioris Alsequae Nasi. 



Origin. From the nasal process of the superior maxilla. 



Insertion. An internal fasciculus into the wing of the 

 nose, and by the outer portion into the orbicularis oris and 

 the skin of the upper lip. 



Nerve Supply. The infra-orbital branch of the facial. 



Action. To raise the wing of the nose and the upper 



HP. 



Levator Ang-uli Oris. Fig. 3. 



Origin. From the canine fossa of the superior maxil- 

 lary bone, below the infra-orbital foramen. 



Insertion. Into the orbicularis oris at the angle of the 

 mouth. 



Nerve Supply. The facial by the infra-orbital branch. 



Action. To raise the angle of the mouth. 



DISSECTION. 



The parotid gland and masseter muscle are covered by a dense layer of 

 fascia, the parotid and masseteric, a prolongation of the superficial layer of 

 the cervical fascia upward to the zygomatic arch. Be very careful in remov- 

 ing this fascia to leave the branches of the facial nerve, the auriculo-temporal 

 nerve, the transverse facial artery, Stenson's duct, and the detached portion of 

 the parotid gland (glandula socia parotidis) uninjured upon the masseter muscle. 



