The most common site of congenital blockage in the duct marked by an arrow in the picture below is at the?
A. At the upper end.
B. In the middle.
C. At the lower end.
D. Whole of the duct.
Ans;C.At the lower end
The duct marked by an arrow in the above picture represents the Nasolacrimal duct.
- The nasolacrimal duct is about 0.5 in. (1.3 cm) long and emerges from the lower end of the lacrimal sac.
- The duct descends downward, backward, and laterally in a bony canal and opens into the inferior meatus of the nose. The opening is guarded by a fold of mucous membrane known as the lacrimal fold. This prevents air from being forced up the duct into the lacrimal sac on blowing the nose.
- The most common site of congenital blockage is at the lower end of the duct.