258 ANATOMY AND PHYSIOLOGY FOR NURSES 

 THE APPENDAGES OF THE EYE 



The appendages of the eye are the eyebrows, eyelids, 

 eyelashes, conjunctiva, caruncula lacrimalis, and lacrimal 

 apparatus. 



The eyebrows (supercilia) are two prominent arches 

 of integument, covered with short, thick hairs, which form 

 the upper boundary of the orbits. They serve to shade 

 the eyes from a too vivid light, and protect them from the 

 particles of dust and moisture that roll down the forehead. 



The eyelids (palpebrae) are two valvular layers 

 placed in front of the eye, serving, by their closure, to 

 defend it against injury; they have been called the "blinds 

 of the eye." When drawn up, they disclose an elliptic 

 space (fissura palpebrarum) , the angle of which forms the 

 outer and inner canthi. The inner canthus is prolonged 

 for a short distance inward toward the nose, and a tri- 

 angular space is formed which is called the lacus lachry- 

 malis. At the commencement of the lacus lachrymalis, 

 upon each of the two lids, is a small, angular projection, the 

 papilla or tubercle, which forms the entrance to the lacrimal 

 canal. 



The tegumentary areolar tissue of the eyelids is re- 

 markable for its looseness and absence of fat; it is particu- 

 larly liable to serous infiltration after injury to these 

 parts. 



The tarsal cartilages contribute to the support of 

 the eyelids. They are semilunar in form, the superior 

 being about J inch in breadth at its middle and taper- 

 ing toward each extremity. The inferior is an elliptic 

 band, narrower than the superior, and is situated in the 

 substance of the lower lid. Its upper border is flat, and 

 corresponds with the edge of the upper cartilage. The 

 lower is held in place by the fibrous membrane, which is 

 firmly attached to the periosteum around the margin of 

 the orbit- 



