TENSOR TARSI. 407 



Semilunaris ; its principal use appears to be, to give increased 

 facility of motion to the globe in an outward direction, from the 

 looseness of its connexions between the lids and the ball. 



The muscles of the eye, described at page 304, &tc.. are to 

 be ranked among the auxiliary appurtenances of that organ. 



[At the internal corner of the eyelids is a small muscle which 

 I had occasion to observe for the first time in the winter of 

 1821-2. It has, I believe, escaped the notice of other anato- 

 mists till the present time. This muscle is about three lines 

 broad and six lines long, and arises from the posterior flat sur- 

 face of the OS unguis near its junction with the os ethmoides, 

 and passes forwards and outwards, lying on the posterior face 

 of the lachrymal ducts. As it approaches the junction of the 

 lids, it splits into two parts, nearly equal, each of which is 

 appropriated to a duct, and inserted along its course almost to 

 the punctum lachrymale. 



To get a distinct view of it, the eyelids must be separated 

 from the eye and turned over the nose, leaving the tendinous 

 attachment of the orbicularis and ciliaris muscle. The semi- 

 lunar valve is brought into sight by this process, which must be 

 dissected away, and also the fat and cellular membrane beneath 

 it. The muscle is now seen, and by passing bristles through 

 the lachrymal ducts its connexion with them is rendered evident, 

 at the same time that we get a good idea of its size, origin and 

 insertion. 



While making this inspection, by turning the muscle a little 

 aside, we shall be convinced of another fact of some impor- 

 tance, and which is equally neglected by most anatomists. It 

 is, that behind the tendon of the orbicularis muscle a ligamen- 

 tous matter passes from the corners of the eyelids to the flat 

 part of the os unguis, which ligament would keep the corner 

 of the eyelids from being deformed, notwithstanding the tendon 

 of the orbicularis be cut through in the treatment of fistula 

 lachrymalis. The lachrymal ducts are included in this ligament, 

 and pass through it into the sac instead of going along the 

 edges of the eyelids, as is commonly asserted. 



This muscle appears to be intended to keep the puncta in 



