The Lachrymal Apparatus

The lachrymal gland consists of two portions: an orbital or superior portion and a palpebral or inferior portion. The orbital portion is enclosed in a capsule and slung from the orbital margin by its suspensory-ligament. Beneath, it rests on the fascial expansion of the levator palpebrae muscle. The palpebral portion is smaller than the orbital and is partially separated from it by the fascial expansion. It lies on the conjunctiva at the upper and outer portion of its fornix. The lachrymal gland opens by several fine ducts into the fornix of the conjunctiva. It is sometimes the seat of malignant tumors, but rarely of other troubles. The remaining lachrymal passages running from the eye to the nose are frequently the seat of inflammation, causing suppuration and obstruction.

The puncta lachrymalia in the top of each papilla lead into the canaliculi. These enter the lids perpendicular to their margin and turning at right angles join just before entering the upper end of the lachrymal sac.

The lachrymal canal, embracing the sac and lachrymonasal duct, each about 12 mm. in length, extends from just above the internal tarsal ligament or tendo oculi to the inferior meatus of the nose. The sac is strengthened posteriorly by the tensor tarsi or muscle of Horner, which passes from the lachrymal bone to the puncta, and by some fibres of the palpebral ligament. Anteriorly is the strong palpebral ligament. Below the palpebral ligament, the sac is comparatively weak and here it is that distention occurs and pus makes its exit. The duct lies in the lachrymal groove in the bone. It is narrower than the sac, being 3 to 4 mm. in width, and is the usual seat of obstructions. To keep the passage open in case of stricture probes are passed. The direction of the duct is slightly outward and more markedly backward, being indicated approximately by a line drawn from the inner canthus to just behind the second premolar tooth. In probing the duct it is customary to first open the punctum in the lower lid - which is normally only one mm. in size - by slitting it and the caniculus with a Weber's canaliculus knife. The probe is directed horizontally until the sac is entered, which is recognized by the end of the probe striking the bone; it is then raised vertically and passed downward and backward and sometimes slightly outward until it can be seen in the inferior meatus of the nose about 1 cm. behind the anterior end of the inferior turbinated bone.

Fig. 98.   Lachrymal apparatus.

Fig. 98. - Lachrymal apparatus.