218 



Organ of Vision. 



294. The Eve and the Muscles of the Eyelid. 



The eyelids, Palpebrae, are moveable portions of integument, 

 whose free margins limit the Rima palpebrarum ; this latter ends in an 

 acute outer angle, Cantliiis extcrnus, and a rounded inner angle, 

 Canthus mternus. The eyelashes, Cilia, are attached to the free edges 

 of each eyelid. The tarsi, Tarsus superior and Tarsus inferior, are placed 

 in the mucous membrane of the eyelids, and are attached to the upper 

 and lower margins of the orbit by the strong Ligamenta tarsi supe,rioris 

 et inferioris ; the thick Ligamcntum cantld internum runs from the inner 

 canthus to the nasal process of the superior maxillary bone, and the 

 broad Ligamentum canthi externum from the outer canthus to the frontal 

 process of the malar bone. The ciliary muscle, M. ciliaris, lies upon 

 the tarsus. 



Upon the posterior surface of the tarsal cartilages, or surrounded 

 by them, are the sebaceous Meibomian glands (30 40 in the upper 

 lid, 25 35 in the lower), whose ducts open on the posterior part of 

 the free margin of the lids, and secrete the Sebum palpebrale. sen Lema 

 (Fig. 295, 296). 



The eyebrows, Supercilia, are the arched eminences of integu- 

 ment, along the upper circumferences of the orbits, which support numerous 

 short, thick hairs. 



