Image: The sphenopalatine nerve and its branches. Gray’s Anatomy, 1910 ed.
Medical Term of the Season: Sphenopalatine ganglioneuralgia
Sphen-: Wedge-shaped, or related to the sphenoid bone of the skull
-palatine: relating to the palate of the mouth
Ganglio-: A tissue mass, most often a bundle of nerve cell bodies.
-neur-: Neural, of the head, or in the head.
So sphenopalatine ganglioneuralgia is neuralgia related to the sphenopalatine ganglia. Most commonly, this is what we know as brain freeze, or an ice-cream headache.
The touching of a cold substance to the roof of the mouth (such as in swallowing) causes a rapid constriction of blood vessels in the sinuses. When the cold substance is removed and the area quickly re-warms, an extreme “rebound” dilation of the blood vessels occurs, triggering the pain sensors in the palate.
Since the pain sensors in the palate relay their signals through the trigeminal nerve (similar to most headaches due to physical causes), the brain interprets the accidental trigger as a legitimate “headache”, and gives you that sharp pain sensation until the signal is corrected by the readjusted palate!
There is another theory regarding the source of cold-stimulus pain, which posits the origin is actually in the anterior cerebral artery, and not the sphenopalatine ganglia, but research supporting both theories also shows that the pain can be lessened by eating cold treats slowly, and not using a straw in cold beverages.
It can also be mitigated once it starts by drinking a warm beverage, or pressing the tongue against the roof of the mouth to more quickly re-warm the area.
Scientific American Mind, Vol 19, Issue 1, 2008. “Brain Freeze” by Mark Andrews.
British Medical Journal, 10 May 1997. “Ice Cream Headache.”