CILIARY MUSCLE. 



307 



chloride of palladium, the annular plexus which is expanded over the 

 whole internal side of this muscle. 



The size of the muscle, its texture, and the relative development of its 

 meridianal and circular fibres, are subject to considerable individual 

 variations. These variations are in immediate relation to the length 

 of the optic axis, on which the refraction of the eye, that is to say, its 

 long or short-sightedness, depends. 



In hypermetropic persons,* whose optic axis is generally short, 

 the anterior part of the muscle, that is to say, Miiller's annular muscle, 

 is relatively largely developed ; in consequence of which the muscle 

 projects anteriorly in the direction of the anterior chambers of the eye, 

 and is upon the whole of smaller size. 



Fig. 364. 



Fig. 364. Section from the ciliary region of a myopic (short-sighted) eye. 



In myopics (whose optic axis is considerably longer) the anterior 

 circular muscular fasciculi are very feebly developed ; the muscle itself 

 consists chiefly of meridianal and radiating fasciculi, and the anterior 

 part of the muscle consequently appears to be displaced backwards 

 to a considerable extent ; and the whole muscle is longer. 



In the domestic animals the muscle consists exclusively of longi- 

 tudinal fasciculi. In the Pig, however, circular fasciculi are found in 

 the posterior part.t 



4. The nerves of the choroid (nervi ciliares) belong to the 

 third and fifth pairs, and to the sympathetic. The long set, 



* A. Iwanoff, Beitrage zur Anatomic des Ciliarmuskels in the Archiv fur 

 Ophthalmoloyie, Band xv., Abtheil iii., p. 284. 



f A. Iwanoff and A. Rollett, Archiv fur Ophthalmologie, Band xv., 

 Abtheil i. 



x 2 



