Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

The accessory structures of the eye include the eyebrow, eyelashes, and eyelid. The eyebrow andeyelashes serve a protective function. The eyelid is lined with mucous membrane (called conjunctiva)which continues over the surface of the eyeball. The corner where the upper and lower eyelids joinis called the canthus, the medial canthus being on the innerside, the internal (temporal) canthus beingon the outer side. The lacrimal apparatus consists of four structures: the lacrimal glands, lacrimalducts, lacrimal sac, and nasolacrimal duct. These structures perform the functions of secreting anddraining tears on the surface of the eyeball (Figures 76 and 77).Figure 76. EYEBALL (sagittal view) Figure 77. EYEBALL (frontal view)°.Canthllt _. * i/ed[¢lL (n¢iCL) T,!spore][c6nthua cant busL_c rlm_t Ila.C '_ "antiLagrLmaL ducte- , LacrJLelat ILnnds"_";:'_'_-)"'_ ":_" i_xcretory ductlCo nJ uric t I vaNa soLae r I ran J_'_J]Figure 78. LACRIMAL APPARATUS419