THE EYELIDS. 355 



muscles, and muscular fibres of the occipito-frontales and 

 orbiculares palpebrarum. The hairs are arranged in two 

 rows, the superior inclining downward and outward, the 

 inferior upward and outward. Both rows converge in the 

 middle, so as to cause a fullness and regular prominence. 



The function of the eye-brow is to shade the eye from 

 too strong light, and to shield it from particles of dust, 

 and from the perspiration. 



The eyebrow can be elevated by the occipito frontalis, 

 depressed by the orbicularis palpebrarum, and drawn to- 

 wards the nose by the corrugator supercilii. 



Blood-vessels of the eyebrows. The arteries come from 

 the ophthalmic and temporal. The veins have correspond- 

 ing names with the arteries and discharge into the cavern- 

 ous sinus. 



Nerves of the eyebroivs. These come from the ophthalmic 

 branch of the fifth pair and the facial. 



The eyelids (palpebrce) form two movable curtains, sit- 

 uated in front of the eye, and. adapted to protect this organ 

 from injury. The eyelid in man consists of two por- 

 tions, a superior and an inferior lid; while in some animals 

 there is a third. When the lids are open, the points of 

 connection at their inner and outer extremities are called 

 canthij angles, or commissures. 



The internal canthus presents a triangular space called 

 the lacus lachrymalis, which encloses a little body, the 

 caruncula lachrymalis. On the free margin of each lid, at 

 the inner extremity, and a little to the outside of the car- 

 uncle, is seen an eminence called the lachrymal papilla or 

 tubercle. In each of these papillae, at the apex, is seen a 

 small opening, the punctum lachrymale, which is the com- 

 mencement of the lachrymal canals, conducting the tears 

 to the lachrymal sac. 



The structure of each eyelid consists of the integument, 

 muscle, tarsal cartilage, tunica conjunctiva and Meiboniian 

 glands. 



The integument is thin, delicate, loose, and remarkable 

 for the entire absence of fat, which would, in this situation, 



