26 



HEAD AND NECK 



three lamellae: a superior lamella, which blends with the 

 upper part of the palpebral fascia and is attached with it 

 to the anterior surface of the upper tarsus ; an intermediate 

 lamella, which is connected with the upper border of the 

 upper tarsus ; and an inferior lamella, which gains insertion 

 into the upper fornix of the conjunctiva. It raises the 

 upper eyelid by pulling on the upper tarsus, and at the same 

 time elevates the upper fornix of the conjunctiva. It is sup- 

 plied by the oculo-motor nerve. 



Vessels and Nerves of the Eyelids. At the medial com- 

 missure two arteries, the palpebral branches of the ophthalmic, 



Frontal bon 



M. orbicularis oculi 



Palpebral fascia \^5^ 



Superior conjunctival fornix 

 Superior tarsus 



Conjunctival recess 



Inferior conjunctival fornix 

 Palpebral fascia < 

 FIG. 8. Diagram of the Structure of the Eyelids. 



pierce the palpebral fascia and run laterally, one in the upper 

 and one in the lower lid. At the lateral margin of the 

 orbit, one or more branches of the lacrimal division of the 

 ophthalmic pierce the palpebral fascia and anastomose with 

 the palpebral branches of the ophthalmic. An arterial arch, 

 arcus tarseus, is thus formed close to the margin of each 

 eyelid, between the orbicularis muscle and the tarsus. 



The veins run medially towards the root of the nose and 

 open into the frontal and angular veins. 



The nerves are more numerous and come from a number 

 of different sources. The motor filaments for the various 

 parts of the orbicularis oculi are derived from the temporal 



