DISSECTION OF THE HEAD AND NECK 



375 



ORGAN OF VISION (ORGAN ON VISUS). 



This includes the eyeball (bulbus oculi), the optic nerve (N. 

 options), and the accessory organs of the eyeball (organa oculi 

 accessories). The latter, including the extrinsic muscles of the 

 eye, orbital fasciae, eyelids and eyebrows, conjunctiva, and lacri- 

 mal apparatus, as well as the optic nerve, have already been 

 studied. The eyeball itself should now be examined. 



The student should provide himself with several eyeballs 

 from the ox and pig; some of these may be dissected fresh, 



FIG. 179. 



Linea visus (line or axis of vision) Axis optica (axis of the optical system, ocular axis) 



~~1 . Vertex corneae 

 Camera oculi anterior (anterior chamber) 



Camera oculi posterior ^^TZ- H^-^^X^ Cornea. 

 (posterior chamber) >O^\ I IV? \^V Iris 



Processus ciliaris . 



Zonula, ciliaris - ^ 

 [Zinni] 



Lens crystallina-- 



,. Conjunctiva bulbi 

 -M. ciliaris 

 .-.Pars ciliaris retinae 

 Ora serrata 

 -Nodal point 



Equatorial 

 diameter 



-Pars optica retinae 



Corpus vitreunv 



Papilla N.optici-- 

 Excavatio papillae N. optici-' 



*-Fovea centralis of the macula lutea 



ill. __.N. opticus 



Schematic section in the horizontal meridian of the right eyeball. (After Toldt, Anat. Atlas, Wien, 



1903, 3 Aufl., p. 892, Fig. 1334.) 



others after hardening in formalin. Sections in different planes 

 should be made of eyeballs hardened in formalin. These may 

 easily be permanently preserved in formalin gelatin. The eye- 

 balls should first be cleaned. Remove the conjunctiva, eye- 

 muscles, fat, and capsule of Tenon. This is best done by grasp- 

 ing the conjunctiva and fascia bu^bi with the point of the forceps 

 close to the limbus corneae and snipping through them with fine 



