Lymphatic drainage No lymphatic vessels have been observed draining the lacrimal gland. Nerve supply The lacrimal gland is innervated by the lacrimal nerve, which is the smallest branch of the ophthalmic nerve, itself a branch of the trigeminal nerve (CN V). After the lacrimal nerve branches from the ophthalmic nerve it receives a communicating branch from the zygomatic nerve. This communicating branch carries postganglionic parasympathetic axons from the pterygopalatine ganglion. The lacrimal nerve passes anteriorly in the orbit and through the lacrimal gland providing parasympathetic and sympathetic innervation to it. Parasympathetic innervation The parasympathetic innervation to the lacrimal gland is a complex pathway which traverses through numerous structures in the head. Ultimately this two-neuron pathway involving both a preganglionic and postganglionic parasympathetic neuron increases the secretion of lacrimal fluid from the lacrimal gland. The preganglionic parasympathetic neurons are located in the superior salivatory nucleus. They project axons which exit the brainstem as part of the facial nerve (CN VII). Within the facial canal at the geniculate ganglion the axons branch from the facial nerve forming the greater petrosal nerve. This nerve exits the facial canal through the hiatus for the greater petrosal nerve in the petrous part of the temporal bone. It emerges to the middle cranial fossa and travels anteromedially to enter the foramen lacerum. Within the foramen lacerum it joins to the deep petrosal nerve to form the nerve of the pterygoid canal and then passes through this canal. It emerges in the pterygopalatine fossa and enters the pterygopalatine ganglion where the preganglionic parasympathetic axons synapse with the postganglionic parasympathetic neurons. The postganglionic neurons then send axons which travel with the zygomatic nerve to enter the inferior orbital fissure. As the zygomatic nerve travels anteriorly in the orbit it sends a communicating branch to the lacrimal nerve which carries the postganglionic parasympathetic axons. The lacrimal nerve completes this long pathway by travelling through the lacrimal gland and sending branches to which it provides parasympathetic innervation to increase the secretion of lacrimal fluid. Sympathetic innervation Sympathetic innervation to the lacrimal gland is of less physiologic importance than the parasympathetic innervation, however there are noradrenergic axons found within the lacrimal gland. Their cell bodies are located in the superior cervical ganglion. Clinical significance In contrast to the normal moisture of the eyes or even crying, there can be persistent dryness, scratching, itchiness and burning in the eyes, which are signs