566 



DISSECTION OF THE FACE. 



Appendages 

 of the eye. 



Eyebrow. 



Eyelids 



Upper 

 larger. 



Shape of 

 margin. 



Papilla. 

 Punctum. 



Hairs and 

 apertures. 



Eyelashes. 



Apparatus 

 for the 

 tears. 



Dissection. 



Apertures 

 in eyelids. 



in the columna nasi below the level of the anterior end of the septal 

 cartilage, being attached to this and to its fellow of the opposite side 

 by fibrous tissue, and reaches nearly to the superior maxillary bone. 



THE APPENDAGES OF THE EYE. 



The APPENDAGES OF THE EYE include the eyebrow, the eyelid, 

 and the lachrymal apparatus. 



The eyebrow (supercilium) is a curved eminence just above the eye 

 which is placed over the orbital arch of the frontal bone. It consists 

 of thickened integuments, and its prominence is in part due to the 

 subjacent orbicularis palpebrarimi and corrugator supercilii muscles. 

 It is furnished with long coarse hairs, which are directed outwards, 

 and towards one another. 



The eyelids (palpebrre) are two movable semilunar folds in front 

 of the eye, which can be approached or separated over the eyeball. 

 The upper lid is the larger and more moveable, and descends below 

 the middle of the eyeball when the two meet ; it is also provided 

 with a special muscle to raise it. The interval between the open 

 lids is named the palpcbral fissure. Externally and internally they 

 are united by a commissure or canthus. 



The free border of each lid is somewhat thickened, and presents 

 a narrow surface which meets the opposite lid when the aperture, is 

 closed, and is bounded towards the eyeball by a sharp smooth edge ; 

 but at the inner end, for about a quarter of an inch from the 

 commissure, it is somewhat thinner and more rounded. At the 

 spot where the two parts join is a small white eminence (fig. 207), 

 the papilla lachrymalis ; and in this is the punctum lachrymale, or the 

 opening of the canal for the tears. 



This margin is provided anteriorly with the eyelashes, and near 

 the posterior edge with a row of small openings of the Meibomian 

 glands ; but both the cilia and the glands are absent from the part of 

 the lid which is internal to the opening of the punctum lachrymale. 



The eyelashes (cilia) are two or more rows of curved hairs, which 

 are fixed into the anterior edge of the free border of the lid ; they 

 are largest in the upper lid, and diminish in length from the centre 

 to the sides. The cilia of the two lids are convex to one another, 

 and cro?s when the lids are shut. 



LACHRYMAL APPARATUS (fig. 207). The lachrymal gland, puncta, 

 canals, and sac, with the nasal duct, constitute the apparatus by 

 which the tears are formed and conveyed to the nose. 



Dissection. A bristle or blunted pin should be introduced into 

 each lachrymal canal through the punctum. The lachrymal sac 

 will appear on the removal of the internal tarsal ligament and of the 

 areolar tissue from its surface as it lies on the lachrymal bone. The 

 prolongation from the internal tarsal ligament over the sac should 

 be defined and understood before its removal (p. 568). 



The puncta lachrymalia (*), one on each lid, are the openings of 

 the lachrymal canals. Each is situate on the free margin of the lid, 

 about a quarter of an inch from the inner canthus, and at the 

 summit of the papilla lachrymalis. 



