The Sphenopalatine Ganglion (SPG) is known to play an integral role in the pathophysiology of a wide variety of orofacial pains involving the jaws, sinuses, eyes and the trigeminal autonomic cephalalgias. It supplies direct parasympathetic innervation to the trigeminal and facial nerves. Sympathetic innervation from the superior sympathetic chain passes thru the SPG to the trigeminal and facial nerves.

This paper reviews relevant and significant literature on SPG Blocks and Neuromodulation published in peer reviewed medical and dental journals. Neuromuscular Dentistry employs ULF-TENS to relax musculature and simultaneously provide neuromodulation to the ganglion. Conclusion: The effects of ULF-TENS on the autonomic nervous system acts on the Limbic System and Hypothalamus (H-P-A) to address Axis II issues during neuromuscular dental proce- dures. It also directly affects the autonomic component of the trigeminal nerve involved in almost all headaches and migraines as well as the Myofascial and Joint disorders of TMD.

Sphenopalatine Ganglion Block; Sphenopalatine Ganglion (SPG) Neuromodulation; ULF-TENS; Trigeminal Autonomic Nervous system; Neuromuscular Dentistry


The SPG is the largest parasympathetic ganglion of the head. The SPG should be considered an important part of the brain even though it is located within the pterygopalatine fossa (not the cranial vault) on the maxillary division of the trigeminal nerve. The maxillary artery is also located within the pterygopalatine fossa. The SPG is known by several names, including the nasal ganglion, Sluder’s ganglion, the pterygopalatine ganglion (due to location), and Meckel’s ganglion.

According to Ho, et al. [Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review. J Headache Pain. 2017;18(1):118], the sphenopalatine ganglion “is the largest and most superior ganglion of sensory, sympathetic and parasympathetic nervous sys- tem. It has the largest collection of neurons in the calvarium outside of the brain. It is also the only gang- lion having access to the outside environment through the nasal mucosa. SPG gives rise to greater and lesser palatine nerves, nasopalatine nerves, superior, inferior and posterior lateral nasal branches, as well as the pharyngeal branch of the maxillary nerve. There are also orbital branches reaching the lacrimal gland.” The excellent reference list from Ho’s article is recommended for anyone wishing to better understand sphe- nopalatigne ganglion treatment possibilities.

The access of the sphenopalatine ganglion to the outside environment via the nasal mucosa is critically important, as it led Dr. Greenfeld Sluder to the early understanding of the importance of the SPG. His early work with remote dysfunction associated with the SPG was a leap in a new direction into understanding the autonomic foundations for pain and other dysfunctions.