Traankanalen

Traankanalen, the Dutch term for tear ducts, are part of the lacrimal drainage system that carries tears from the eye to the nasal cavity. They help maintain the tear film on the ocular surface and clear excess fluid.

Anatomy and pathways: Tears exit the eye through small openings called puncta located at the inner margins of the upper and lower eyelids. From there, tears pass through the lacrimal canaliculi (superior and inferior) into the lacrimal sac, which sits in the lacrimal fossa. The nasolacrimal duct then carries tears from the sac to the inferior meatus of the nasal cavity. Two valves regulate flow: the valve of Rosenmüller at the junction between canaliculi and the lacrimal sac, and the valve of Hasner at the distal end of the nasolacrimal duct.

Function: The traankanalen continuously drain tears produced by the lacrimal glands, preventing overflow and aiding tear clearance. This drainage also contributes to ocular surface lubrication and helps remove microorganisms from the conjunctival surface.

Clinical relevance: Obstruction of the nasolacrimal duct is a common cause of epiphora (excess tearing) and recurrent eye infections. Congenital nasolacrimal duct obstruction is frequent in infants and may improve with age or respond to lacrimal sac massage. Persistent obstruction in adults can require imaging and procedures such as dacryocystorhinostomy (DCR) to create an alternate drainage pathway. Management may include probing, stenting, or other reconstructive techniques depending on the location and severity of the blockage.