THE EYE 381 



The appendages of the eye include the eyebrows, eyelids, 

 conjunctiva, the lacrymal gland and sac, and the nasal duct. 

 The last three belong to the " lacrymal apparatus. " 



The eyebrows (supercilia) are two prominent tracts of integu- 

 ment above the orbit, covered by thick hairs. They are 

 connected with the orbicularis, corrugator supercilii, and 

 occipitofrontalis muscles. 



The lids (palpebrse) protect the eyeball. Each is composed 

 of thin integument, areolar tissue, muscular fibers, the tarsal 

 cartilage and ligament, Meibomian glands, and conjunctiva; 

 the upper lid, which is also the more movable, contains, in 

 addition, the aponeurosis of the levator palpebrse. 



The lids are separated, when opened, by a space, the fissura 

 palpebrarum, and are united at the angles (canthi). The 

 outer canthus is sharp, and the inner is more obtuse. At 

 the inner canthus, on each lid, is found the lacrymal tubercle, 

 pierced by the punctum lacrymale, the upper opening of the 

 lacrymal canal. 



The tarsal cartilages (tarsi) are two plates of dense fibrous 

 tissue, one in each lid. Into the anterior surface of the upper 

 the levator palpebne is inserted. Each is attached at the 

 inner angle to the tendo oculi or internal tarsal ligament; 

 at the outer angle to the external tarsal ligament, which is 

 inserted into the malar bone. 



The tendo oculi or palpebrarum is Y-shaped. The stem is 

 attached to the nasal process of the superior maxilla, and 

 each arm to one of the tarsal cartilages. 



The palpebral ligament is a fibrous membrane attached to 

 the tarsal cartilages and to the corresponding margin of the 

 orbit. 



The Meibomian glands (sebaceous) lie on the* inner surface 

 of the lids, between the tarsal cartilages and the mucous mem- 

 brane. In the upper lid there are about thirty; in the lower, 

 fewer. 



The lashes (cilia) are short, thick hairs forming a double 

 row on the free margin of each lid. Above they are longer and 

 more numerous. 



The conjunctiva is the mucous membrane of the eye. The 

 palpebral portion is very thick and vascular, and forms ;it 

 the inner canthus a fold known as the plica semilunaris. The 

 ocular portion is loosely connected to the sclerotic, but over 



