13.05. LACRIMATION.

In the big book I read that the postganglionic pathway is uncertain, and that employment of the zygomatic nerve, the zygomaticotemporal nerve and a little branch that communicates from there to the lacrimal nerve is logical, but not necessarily proven. Probably just about any way to get from the ganglion to the gland is a viable postganglionic pathway. Just be very sure you know the source cranial nerve, the ganglion and the destination. Please restate them now.

Facial nerve, pterygopalatine ganglion, lacrimal gland.

So in what direction is tear fluid distributed across the eye by blinking?

From superior and lateral to inferior and medial.

What features of the eyelids drain tear fluid away from the surface of the eye? Where are they located?

Lacrimal puncta. Medially.

Trace the path of tear fluid from the superior and inferior lacrimal canaliculi.

Lacrimal punctum, lacrimal canaliculus, nasolacrimal duct, inferior meatus of nasal cavity. I am not sure why the lacrimal sac is not on the study list.

What muscle of facial expression can provide some tonic tension in the lower eyelid to keep the inferior lacrimal puncta in the lacus lacrimalis (lake of tears) so it will drain properly?

Orbicularis oculi, specifically the part that is called "orbicularis oculi pars lacrimalis."

Into what structures do the lacrimal puncta open directly?

Superior and inferior lacrimal canaliculi.

Where in the orbit is the lacrimal gland located?

Superolaterally and anteriorly.

What happens if that muscle fails to perform this function?

Tears can spill down the cheek, which may cause a dry eye and irritated skin.

What study list terms would you use if you added a little more content to this story?

The preganglionic parasympathetic course includes the greater petrosal branch of the facial nerve and the nerve of the pterygoid canal.