Involvement of the Ipsilateral Tongue, an Intraoral Structure of Referred Pain due to Entrapment of the Greater Occipital Nerve

Abstract

This study reports a rare case of referred pain in the trigeminal nerve distribution caused by entrapment of the greater occipital nerve (GON). Notably, the pain extended to the ipsilateral tongue, an unusual intraoral involvement. GON entrapment can lead to sensitization in secondary nociceptive neurons within the trigeminocervical complex (TCC), which receives signals from both trigeminal and occipital nerves, causing referred facial pain. A 55-year-old female presented with chronic left temporo-occipital pain, along with pain in her left periorbital area, ear canal, gum, and a 20-year history of atypical facial pain on her left tongue and lower lip. Following GON decompression, her temporo-occipital pain and facial symptoms improved, with a significant reduction in burning pain on her tongue and resolution of lip tingling. The TCC, comprising convergent inputs from trigeminal and occipital nerves, is the anatomical basis of referred craniofacial pain. Chronic GON entrapment can sensitize second-order neurons in the TCC and medullary dorsal horn, explaining this unusual referred pain to the intraoral structures.

Keywords: entrapment neuropathy; greater occipital nerve; referred pain; tongue; trigeminal nucleus; trigemiocervical complex.

Figure 1

Schematic drawing showing the distribution of craniofacial pain caused by greater occipital nerve (GON) entrapment. (a) The location (gray areas) of temporal–occipital pain along with left periorbital, preauricular, and mental pain. It has also extended to the nape of the neck and shoulders. It was accompanied by dull pain such as a bruise in the left ear canal (black circle). (b) Distribution (gray areas) of left tongue and lip pain diagnosed as atypical facial pain for 20 years. (c) Drawing showing improvement and reduction in the extent of left tongue and lip pain.

Figure 2

Intraoperative images showing the entrapment of the greater occipital nerve (GON) during the decompression. (a) Intraoperative photograph showing the GON (black arrows) located beneath the tendinous aponeurotic edge (white arrows) of the trapezius in the distal trapezius tunnel, lifted with forceps. The inset shows the direction of the image and the location of the incision. (b) Intraoperative photograph showing the tendon edge (black arrows) of the trapezius muscle being gradually dissected and cut. The white arrow represents the GON. (c) Intraoperative image after decompression of the left GON (black arrows) with division of the trapezial aponeurosis (white arrows). The GON region indicated by the black arrow represents the most severely compressed region.