THE EYE. 409 



dividual could shorten so much the internal angle of the eyelids, 

 as to conceal it, along with the puncta, in the internal canthus 

 of the orbit.* 



Of the Nerves of the Orbit. 



In addition to the optic nerve, there are several belonging to 

 the eye and to its auxiliary parts; they are derived from the 

 Motor Oculi or third pair; from the Trochlearis, or fourth pair; 

 from the first branch of the Trigeminus, or fifth pair; and from 

 the Motor Oculi Externus or sixth pair. For an account of 

 which, see Nerves. 



Of the Arteries of the Orbit. 



The Eyeball, and its auxiliary parts, are principally supplied 

 by the Ophthalmic Artery, which, as was mentioned in the ac- 

 count of the Brain, is a considerable branch given off by the 

 Internal Carotid at the fore part of the Sella Turcica. This 

 branch gets into the orbit on the outer side of the optic nerve 

 through the optic foramen, and, after a short course, crosses 

 obliquely above the optic nerve, so as to pass to the internal 

 side of the orbit. It sends off a great many small trunks, which 

 are very inconstant both in their size and origin; they are as 

 follows: 



1. Arteria Lachrymalis arises, commonly, soon after the oph- 

 thalmic has got into the orbit: it goes forwards between the rec- 

 tus superior and the rectus externus muscle, to which it dis- 

 tributes arterioles; it then reaches the lachrymal gland, and 



* Having laboured, first of all, to convince the profession of the existence of 

 this muscle, the next step, as is usual on such occasions, was to vindicate my own 

 pretensions to its discovery, and to attempt to remove such objections as re- 

 quired attention. For the arguments on this subject, I refer to the Philadelphia 

 Journal of Medical and Physical Sciences, of Nov. 1824, edited by Professor 

 Chapman. My claims have been unequivocally admitted by Messrs. Breschet 

 and Jourdan, of Paris, anatomists of unusual distinction, in the translation which 

 they have made of J. F. Meckel's Manual of Anatomy, vol. iii. p. 219; by Gery, in 

 the Melanges de Chirurgie dtrangere, Geneva, 1824, p. 415; and by Professor 

 Giuseppe Trasmondi, in the Arcadica Journal of Rome, &c. vol. xix. p. 1, 1823 

 VOL. II. 36 



