Morphology of the lacrimal sac and nasolacrimal duct in adult human cadaver

The lacrimal sac (LS) is a dilated structure that lies in the lacrimal fossa, and the nasolacrimal duct (NLD) is the continuation of LS from its neck up to the inferior meatus of the nose. A study of 50 specimens of formalin-fixed adult cadavers of both sexes of Indian origin was conducted. The morphological features like length and breadth of LS and NLD, along with the histology of LS has been observed. The mean length of LS and NLD on the right side was 10.5 mm (1.04) and 16 mm (2.6) respectively, whereas the mean breadth of the above structures, on the right side was 6 mm (0.63) and 5.66 mm (0.81) respectively. The mean length of LS and NLD on the left side was 10.57 mm (1.13) and 16.42 mm (2.29), whereas, the mean breadth of the same structure on the left side was 6.71 mm (0.95) and 5 mm (0.81) respectively. The sides did not show any significant statistical difference but when the correlation between the length and breadth of LS is considered, significance was observed in the lacrimal sac of the left side. No variations were observed in the gross structure of LS and NLD. Microscopic study showed the presence of elastic fibers in LS. The importance of LS and NLD is that the blockage of this lacrimal passage is the most common cause of epiphora (watering of the eye). The presence of elastic fibers in this study confirms the hypothesis that the sac elasticity may perform a dynamic role, in forceful evacuation of lacrimal fluid in reverse direction.