BULBUS OCULI 



ganglionated ciliary nerve plexus, and plexuses of arteries 

 and veins associated with the iris and ciliary body. It is 

 continuous with the iris internally, the sclera anteriorly, and 

 the corona ciliaris and the chorioid posteriorly. 



Musculus Ciliaris. The ciliary muscle is composed of in- 

 voluntary muscular tissue. The arrangement of its fibres can 

 be seen only when thin sections of the eyeball are examined 

 under the microscope. It is then obvious that the fibres are 

 disposed in two groups, viz., a radiating and a circular. 



The radiating fibres arise from the deep aspect of the 

 sclera close to the margin of the cornea. From their origin 

 they radiate backwards, in a meridional direction, and gain 



Chorioid (cut 

 edge of) 



Ciliary fol 



Lens 



Ciliary process 



FIG. 229. Posterior view of Lens and Zonula Ciliaris. 

 (Professor Arthur Thomson. ) 



insertion into the chorioid coat in the region of the ciliary 

 processes. The circular fibres consist of two or three bundles 

 placed upon the deep aspect of the radiating portion of the 

 muscle. They form a muscular ring around the outer circum- 

 ference of the iris. The ciliary muscle is supplied by the 

 oculo-motor nerve. It draws the anterior part of the chorioid 

 forwards, and so relaxes the suspensory ligament of the lens, 

 which then becomes more convex on account of its own 

 elasticity. 



Dissection. To obtain a view of the ciliary processes, a 

 frontal section should be made through an eyeball, a short 

 distance anterior to the equator. The portion of the vitreous 

 body which occupies the posterior segment of the eyeball should 

 be carefully removed. When that is done, the deep aspect of 



