WOUND AND FISTULA OF THE LACHRYMAL SAC.
The lachrymal sac, which receives the tears from the canaliculi, is situated in the infundibulum at the upper end of the lachrymal canal and is in great measure protected against external injuries by the prominent orbital edge of the lachrymal bone. Yet violent blows with or without fracture, sometimes lead to rupture of the mucous walls and the formation of a fistula. Wounds made with penetrating bodies, more or less pointed are also liable to involve the sac. The fistulous orifice may be through the skin at the inner canthus or through the mucosa by the side of the carnucle. The cutaneous opening may be a minute orifice from which tears and muco-purulent matter escapes, to mat together the hairs on the side of the face. Sometimes there is a reddish elevation, the size of a pin head, and in fistula through the mucosa this is the rule, and the orifice is elevated so that the tears flow out over the face. For the symptoms of the attendant catarrh of the sac see below. In infected cases with obstruction of the lachrymo-nasal duct, it has been known to extend to the bone and even to open into the sinuses, or tooth follicles. (Gerard, Leblanc).
The condition is found in horses, cattle and dogs.
Treatment. In fistula resulting from simple traumatism, nothing more may be requisite than rest and soothing astringent applications. Sutures are sometimes resorted to but are liable to cause itching and do more harm than good. It is above all important to keep the lachrymo-nasal duct patent, and for this purpose a lead or silver stilet, or a thick catgut suture may be worn in the canal until healing has ensued.