Greater petrosal nerve

The greater petrosal nerve is a nerve in the skull that branches from the facial nerve; it forms part of a chain of nerves that innervates the lacrimal gland.

Structure
The greater petrosal nerve is a branch of the facial nerve that arises from the geniculate ganglion, a part of the facial nerve inside the facial canal. The nerve joins with the deep petrosal nerve (a nerve which carries sympathetic fibers) to form the nerve of pterygoid canal.

Function
This nerve is the parasympathetic root of the pterygopalatine ganglion. It carries preganglionic parasympathetic fibers to the pterygopalantine ganglion for the lacrimal, nasal and palatine glands. In all three cases it induces secretion. It also serves to carry sensory information from the soft palate back to the brain.