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.