22 



ANATOMY. 



THE NASAL BONES. 



'Describe them. They are 2 small bones forming the bridge of the nose by 

 articulation with each other in the median line. They are convex exter- 

 nally, concave internally, and grooved for the external branch of the nasal 

 nerve and for small arteries. They each articulate with 4 bones, the frontal, 

 ethmoid, superior maxillary, and the opposite nasal ; are each developed by one 

 centre of ossification, and have no muscles attached to them. 



THE SUPERIOR MAXILLARY BONES. 



Describe them. They are 2 hollow bones, together forming the upper 

 jaw. Each bone consists of 4 processes, and a body which possesses a large 

 cavity, the antrum of Highmore. 



Describe the Antrum of Highmore. It is a pyramidal cavity in the body of 

 the bone, and opens into the middle meatus of the nose by an aperture which 

 is very small in the recent subject, admitting only a small probe. Its walls are 

 very thin, and are covered internally by a mucous membrane. It presents the 

 Aperture, partly closed by the articulation of the unciform process of the 

 ethmoid with the ethmoidal process of the inferior turbinated ; and that 

 of the maxillary process of the palate with a fissure in the superior maxil- 

 lary ; also by the maxillary process of the inferior turbinated which hooks 

 over the lower edge of the orifice. 



Posterior Dental Canals, on the posterior wall of the cavity. 

 Processes in its floor, formed by the alveoli of the 1st and 2d molar teeth, 



the roots of which occasionally perforate it. 



What other points are presented by the body? The body has 4 



surfaces, the facial externally, the zygomatic 

 posteriorly, the orbital superiorly, and an 

 internal surface forming part of the outer 



14. \W ! ''''Sv 15 wa ^ ^ tne nose anc ^ ^ e cav ^y f ^ ie 



/ """-.. iHnilk mouth. It presents the 



Incisive FOSS&* on the facial surface, 

 above the incisor sockets, for the origin 

 of the depressor alee nasi muscle. 

 Canine jFossa, 1 more externally, for the 



levator anguli oris. 



Infraorbital Foramen? above the ca- 

 nine fossa, transmitting the infraor- 

 bital vessels and nerve, from the in- 

 fraorbital canal in the orbital surface? 

 of the bone. 



FIG. 6. 



