210 VISCERAL ANATOMY. 



What are the Eyebrows ? They are arched elevations of the integu- 

 ment over the supra-orbital arches, are covered with a row of short hairs, 

 and are drawn downwards and inwards by the Corrugator Supercilii muscle. 

 {See page 68.] 



Describe the Eyelids. The Palpebrse, or Eyelids, are two thin, movable 

 folds, placed in front of the eye, for its protection. The upper lid is the most 

 movable one, having its own levator muscle, the Levator palpebne superioris. 

 [See page 68.] The- 



Palpebral Fissure, is the space between their free margins, its outer and 

 inner angles being termed respectively the External Canthus and Inter- 

 nal Canthus. 

 Lacus Lachrymalis, is a small triangular space at the internal canthus, 



between the lids and the globe. 

 Lachrymal Papilla, on the edge of each lid, about % inch from the 



internal canthus. 



Punctum Lachrymale, a minute orifice on each papilla, and the beginning 

 of the lachrymal canal. 



Describe the Structure of the Eyelids. They are composed externally 

 of skin, internally of mucous membrane (the palpebral conjunctiva), and be- 

 tween these lie areolar tissue, the orbicularis muscle, tarsal cartilage, fibrous 

 membrane, Meibomian glands, vessels and nerves. The 



Orbicularis Palptorarum Muscle, is very thin and pale. [See p. 68.] 

 Tensor Tarsi, or Homer's Muscle, [See p. 68] is a portion of the orbicu- 

 laris, compressing the punctum and the sac. 



Tarsal Cartilages, are plates of fibro- cartilage, forming the framework of 

 the lids. The upper one is crescentic in shape, the lower one elliptical 

 and smaller. 



Tarsal Ligaments, are fasciae connecting the tarsal cartilages to the cir- 

 cumference of the orbit. Externally they connect with the malar bone, 

 and are there called the External Canthal Ligaments. 



Tendo Oculi, connects the inner end of 



r IG. 104. 



each tarsal cartilage to the nasal process 

 of the superior maxillary bone. 

 Meibomian Glands,^ are sebaceous glands 

 imbedded in the tarsal cartilages, 30 to 40 

 in the upper lid, 20 to 36 in the lower one. 

 They open along the inner edge of the free 

 border of each lid, and furnish a sebaceous 

 secretion, to prevent adhesion of the lids 

 to each other. 



