ORBITS OF THE EYES. . 167 



Commonly about the middle of the middle meatus of the nose, 

 but varying very much in different subjects, is the orifice of the 

 sinus maxillare, or antrum Highmorianum. Its precise situa- 

 tion and direction are so very uncertain, that its orifice is found 

 with some difficulty in the fresh state, in great numbers of per- 

 sons. Not unfrequently I have seen this orifice high up, under 

 the anterior extremity of the middle spongy bone. 



The inferior meatus of the nose is bounded above by the 

 lower spongy bone, and below by the palate processes. It ex- 

 tends the whole length of the nostril. At the anterior part of 4 

 this meatus above, is the orifice of the ductus ad nasum, which 

 communicates with the orbit of the eye. 



The nostril presents an increased width, anterior to the points, 

 where the spongy bones cease: this space is bounded on the 

 orbitar side by the nasal bone, and the nasal process of the 

 upper maxillary. There is an increase of transverse diameter 

 also at the posterior part of the nostril, behind the points where 

 the spongy or turbinated bones cease. This space is bounded 

 externally by the nasal plate of the palate bone, and by the in- 

 ternal pterygoid process. 



The posterior nares, or orifices of the nostrils, are oval, and 

 are completely separated by the posterior margin of the vomer. 

 In the dried skeleton, on the contrary, the anterior nares have 

 a common orifice, from the deficiency of the bony septum be- 

 tween them. 



SECT. VI. ORBITS OF THE EYES. 



The orbits of the eyes are the conoidal cavities in the face, 

 presenting their bases outwards and forwards, and their apices 

 backwards; so that the diameter of either orbit, if continued, 

 would decussate that of its fellow in the pituitary fossa or sella 

 turcica. Seven bones form the orbit, the os frontis, the os 

 malse, the os maxillare superius, the os planum, the os un- 

 guis, the os sphenoides, and the os palati. Its cavity is some- 

 what quadrangular, besides being conoidal. The angles are 

 particularly well marked, in most subjects, at its base or ori- 

 fice; which resembles an oblong, having its long diameter in 

 some persons placed almost horizontally, and in others oblique- 



