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The orbits are two quadrilateral hollow cones, situated in the upper 

 part of the face, and intended for the reception of the eye-balls, with 

 their muscles, vessels, and nerves, and the lachrymal glands. The cen- 

 tral axis of each orbit is directed outwards, so that the axes of the two 

 continued into the skull through the optic foramina, would intersect 

 over the middle of the sella turcica. The superior boundary of the 

 orbit is formed by the orbital plate of the frontal bone, and by part of 

 the lesser wing of the sphenoid ; the inferior, by part of the malar 

 bone and by the orbital processes of the superior maxillary and palate 

 bone ; the internal by the lachrymal bone, the os planum of the 

 ethmoid and part of the body of the sphenoid ; and the external, by 

 the orbital process of the malar bone and the great ala of the sphenoid ; 

 these may be expressed more clearly in a tabular form : 



Frontal. 

 Sphenoid (lesser wing) . 



Malar. Lachrymal. 



Sphenoid (greater wing). Orbit. Ethmoid (os planum). 



Sphenoid (body). 



Malar. 



Superior maxillary. 

 Palate. 



There are nine openings communicating with the orbit : the optic, 

 for the admission of the optic nerve and ophthalmic artery ; the sphe- 

 noidal fissure, for the transmission of the third, fourth, the three 

 branches of the ophthalmic division of the fifth and the sixth nerve, 

 and the ophthalmic vein ; the spheno-maxillary fissure, for the passage 

 of the superior maxillary nerve and artery to the opening of entrance 

 of the infra-orbital canal ; temporo-malar foramina two or three 

 small openings in the orbital process of the malar bone, for the passage 

 of filaments of the orbital branch of the superior maxillary nerve ; an- 

 terior and posterior ethmoidal foramina in the suture between the os 

 planum and frontal bone, the former transmitting the nasal nerve and 

 anterior ethmoidal artery, and the latter the posterior ethmoidal artery 

 and vein ; the opening of the nasal duct ; and the supra-orbital notch 

 or foramen, for the supra-orbital nerve and artery. 



NASAL FOSSAE. 



The nasal fossae are two irregular cavities, situate in the middle of 

 the face, and extending from before backwards. They are bounded 

 above by the nasal bones, ethmoid, and sphenoid ; below by the palate 

 processes of the superior maxillary and palate bones ; Externally by the 



