ANATOMY IN A NUTSHELL. 535 



Zygomaticus major. — 



Origin. — From the malar bone on its posterior asped of external border. 



Insertion. — Into the angle of the mouth. 



Action. — It raises the lip outward. 



Nerve Supply. — Facial. 



Blood Supply. — Branches from the facial artery. 



Zygomaticus minor. — Stenson's dud the facial artery and vein pass under 

 this muscle. 



Origin. — From the anterior aspect of the external surface of the malar 

 bone. 



Insertion. — Into the angle of the mouth, where it blends with the Levator 

 labii superioris. 



Action. — To raise the lip outward. 



Nerve Supply. — Facial. 



Blood Supply. — Branches from the facial artery. 



Masseter muscle which has been given on page 520. 



Temporal muscle which has been given on page 508. 



LESSON CLXXXI. 



Superior Maxillary Bone. (Plates CCLII-CCLIII). 



The superior maxillary bones are two in number and form the upper jaw. 

 There is only one bone of the face larger than the superior maxillary and that 

 is the inferior maxillary. This bone forms parts of the roof of the mouth, of 

 the floor and outer wall of the nose, of the Moor of the orbit; and parts of the 

 zygomatic and spheno-maxillary fossae, spheno- and pterygo-maxillary fissures. 



The body of the superior maxillary bom 1 is a hollow cube. This hollow 

 is called the antrum of Highmore. 



The external surface, or facial surface of the body, looks forward and out- 

 ward. On this surface we have the following points for consideration: The 

 incisive fossa is just above the incisor teeth and gives origin for the Depressor 

 alse nasi muscle. Just below this fossa a portion of the Orbicularis oris is at- 

 tached to the aveolar border. External to this fossa is the origin of the Com- 

 pressor alse nasi. The canine fossa, which skives origin to the Levator anguli 

 oris, is separated from the incisive fossa by the canine eminence. Tins emi- 

 nence is a vertical ridge produced by the canine tooth. The infraorbital fora- 

 men, which is for the infraorbital vessels and nerve, is above the canine fossa. 

 The margin of the orbit gives attachment to the Levatorlabii superioris propus 

 muscle. 



The posterior, or zygomatic surface is convex and forms pari of the zygo- 

 matic fossa. ()n this surface we have the following points for consideration: 

 Near its center are the openings of the posterior dental canals for the posterior 

 dental vessels ami nerve. The tuberosity, which is at the lower pan of this 

 surface, gives origin to the Internal pterygoid muscle. This tuberosity artic- 

 ulates with the tuberosity of the palate bone and some time- with the external 

 pterygoid plate of the sphenoid. A groove just above this tuberosity i- con- 



