Also called sphenopalatine ganglion block. The sphenopalatine ganglion (SPG) is a group of nerves located behind the sinuses deep in the head.

The SPG is the wheelhouse which transfers parasympathetic and sympathetic nerve fibers from the meninges to the parts of the brain which sense pain and regulate autonomic functions. This autonomic function is something like vessels dilating and contracting. Fibers from the trigeminal nerve (also called the V cranial nerve) also transverse the SPG area. Some doctors have evidence that the SPG is hyper irritable in patients with migraines and resetting this hub of nerves will help patients experience migraine headaches to a lesser degree. There is a recently approved FDA drug delivery device which allows the SPG to be numbed up without any needles and using a common medication.
This method of migraine headache control in very attractive for some patients as it may allow them to decrease their reliance on medications.