OSTEOLOGY. 35 



Posteriorly, a suture between lesser wing and frontal bone. 



It is formed by the orbital plate of frontal and lesser wing of 

 sphenoid. 



The floor is short and flat, and presents: 



Internally, a depression for inferior oblique muscle; 



Middle, the infraorbital groove for nerve and artery; 



Externally, suture of superior maxillary and malar, and 



Posteriorly, suture between palate and superior maxillary. 



It is formed by orbital processes of malar and superior 

 maxilla and orbital surface of palate. 



Inner wall presents crest of lachrymal bone, lachrymal 

 groove, and sutures between ethmoid and sphenoid, and ethmoid 

 and lachrymal. 



It is formed by lachrymal, parts of ethmoid, and sphenoid 

 and nasal process of superior maxilla. 



The outer wall presents suture between malar and sphenoid 

 and orifices of malar canals. It is formed by orbital plate of 

 sphenoid and orbital process of malar. 



The angles of the orbit are four, superior internal and 

 external, inferior internal and external. 



They present the following : 



Superior internal angle; 



Foramen ethmoidal anterior, transmitting anterior eth- 

 moidal vessels and nasal nerve; 



Foramen ethmoidal posterior, transmitting posterior eth- 

 moidal artery and vein; 



Suture between frontal and ethmoid, and frontal and lach- 

 rymal ; 



Superior external angle; 



Sphenoidal fissure, or foramen lacerum anterius, transmit- 

 ting third, fourth, ophthalmic division of fifth and sixth nerves ; 

 orbital branch of middle meningeal artery, filaments of cavernous 

 plexus of sympathetic, recurrent branch of lachrymal artery, and 

 ophthalmic vein and process of dura mater. 



Suture between great wing of sphenoid and malar bone. 



Inferior internal angle; 



Suture between superior maxillary and palate bones, uniting 

 with lachrymal and os planum of ethmoid; 



Inferior external angle; 



Spheno-maxillary fissure, for passage of superior maxillary 

 nerve and its orbital branch, infraorbital vessels, and ascending 

 branches from Meckel's ganglion. 



The CIRCUMFERENCE is bounded : 



Inner side by nasal process of superior maxilla and internal 

 angular process of frontal; 



