Lachrymal Abscess 75 



THE LACHRYMAL APPARATUS 



The lachrymal gland, which is somewhat of the size and shape of 

 an almond, is lodged in the hollow under the external angular process of 

 the frontal bone. To reach the front of the globe, the tears have to 

 pass through the conjunctiva, which they do through half a score of 

 slender ducts, which open on the inner surface of the upper lid. Part 

 of the gland descends behind the lid, and its lower border rests over 

 the superior and external recti, and upon the eye-ball. Being thus 

 poured upon the upper surface of the globe, the tears fall over the 

 front of the eye-ball, washing it completely, whilst the contractions of 

 the orbicularis (p. 72) sweep them constantly inwards, in their course 

 to the puncta lachrymalia. 



Its structure is like that of a salivary gland. It receives its supplies 

 from special branches of the oph- 

 thalmic nerve (p. 61) and artery, 

 and from the sympathetic. 



The puncta lachrymalia are 

 the pin-point openings of the 

 superior and inferior lachrymal 

 canals, which lead from the inner 

 sixth of the margin of the lids to 

 the lachrymal sac. The punctum 

 may be seen on a small papilla on 

 everting the lid. 



At first each canal runs for a 

 slight distance vertically away 

 from the border of the lid, then it 

 alters its course and enters the 

 lachrymal sac. The canal is com- 

 posed of delicate fibrous tissue, and of mucous membrane lined with 

 squamous epithelium. 



The puncta are kept in position against the giobe of the eye by the 

 contractions of the small tensor tarsi, which is, really, a deep part of 

 the orbicularis. It arises from the lachrymal bone, behind the lach- 

 rymal sac, and passes with the canals to the eye-lids. If the punctum is 

 displaced it may be necessary to slit up the canal so that the tears 

 may flow away along the gutter which is then formed. 



The lachrymal sac is the upper, dilated end of the nasal duct, 

 lying in the groove between the nasal process of the superior maxilla 

 and the lachrymal bone. It has the strong tendo oculi in front and 

 the tensor tarsi behind, whilst the lachrymal canals enter its external 

 aspect. 



lachrymal abscess is the result of inflammation of the lining of 

 the sac ; it forms a swelling at the inner corner of the orbit which may 



