Fig. 7. Relationship of the right medial canthal tendon to the nasolacrimal sac: A. Diagrammatic illustration. B. Anatomic dissection. The thick anterior limb of the medial canthal tendon wraps along the anterior upper half of the lacrimal sac to insert onto the anterior lacrimal crest, and the thin posterior limb passes behind the sac to insert onto the posterior lacrimal crest. The upper eyelid tarsus is much greater in height than the lower eyelid tarsus. IO, inferior oblique muscle origin; LCT, lateral canthal tendon; MCT-a, medial canthal tendon-anterior limb; MCT-p, medial canthal tendon-posterior limb; NLS, nasolacrimal sac; SN, sutura notha; T, tarsus.