====== Trigeminal ganglion ======

{{ http://upload.wikimedia.org/wikipedia/commons/8/83/Gray778.png?400}}

The trigeminal [[ganglion]] (or [[Gasserian ganglion]], or [[semilunar ganglion]], or Gasser's ganglion) is a sensory ganglion of the [[trigeminal nerve]] (CN V) that occupies a cavity ([[Meckel's cave]]) in the dura mater, covering the trigeminal impression near the apex of the petrous part of the [[temporal bone]].
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From the ganglion, the 3 major divisions of the trigeminal nerve emerge anteriorly and inferiorly, with the first two (ophthalmic and maxillary divisions) passing anteriorly to enter the [[cavernous sinus]], and the third (mandibular division) descending into the [[foramen ovale]].

===== Relations =====

medial: [[motor]] [[root]] of the [[trigeminal nerve]] and [[sphenoid bone]]

lateral: posterior part of the [[cavernous sinus]], [[petrous apex]] and petrous segment of the [[internal carotid artery]]

anterior: [[cavernous sinus]] and cavernous segment of the [[internal carotid artery]]

posterior: [[prepontine cistern]]

inferior: [[greater petrosal nerve]] and [[middle cranial fossa]]

===== Blood supply =====

small ganglionic branches of the cavernous portion of the [[internal carotid artery]]

accessory meningeal artery (from the [[maxillary artery]], via the [[foramen ovale]])

===== Innervation =====

The ganglionic epineurium is innervated by the nervus spinosus from the mandibular division of the [[trigeminal nerve]] which re-enters the skull via the [[foramen spinosum]].

===== Receptors =====

Earlier studies have shown that the trigeminal ganglion (TG) comprises several receptors and signal molecules that are involved in the process of peripheral [[sensitization]], which influences the development and persistence of [[neuropathic pain]]. Targeting TG can modulate this [[sensitization]] pathway and mediate the pain-relieving effect. So far,there are few studies in which [[modulation]] approaches to TG itself have been suggested so far. "Trigeminal ganglion modulation" and "trigeminal neuralgia" were used as search phrases in the [[Scopus]] Index and [[PubMed]] databases to discover articles that were pertinent to the topic. Kc et al. in a review, addressed the role of the trigeminal ganglion in TN and underlying [[molecule]]s and [[neuropeptide]]s implicated in trigeminal pain pathways in processing pathological [[orofacial pain]]. They also reviewed different [[modulation]] approaches in TG for [[trigeminal neuralgia treatment]]. Furthermore, they discussed the prospect of targeting trigeminal ganglion to manage such intractable pain
((Kc E, Islam J, Park YS. Trigeminal ganglion itself can be a viable target to manage trigeminal neuralgia. J Headache Pain. 2022 Nov 24;23(1):150. doi: 10.1186/s10194-022-01512-x. PMID: 36424545.)).

===== Approaches=====
Traditionally, a [[pterional approach]] is utilized to access the [[Meckel cave]]. Depending on the tumor location, extradural dissection of the Gasserian ganglion can be performed. An [[endoscopic endonasal approach]] could potentially avoid a [[craniotomy]] in these cases. 

An endoscopic endonasal approach as well as a lateral approach to the Meckel cave on six anatomic specimens, to access the Meckel cave endoscopically, a complete sphenoethmoidectomy and maxillary antrostomy followed by a transpterygoid approach was performed. For lateral access, a pterional craniotomy with extradural dissection was performed. 

The endoscopic endonasal approach allowed adequate access to the Gasserian ganglion. All the relevant anatomy was identified without difficulty. Both approaches allowed for a similar exposure, but the endonasal approach avoided brain retraction and improved anteromedial exposure of the Gasserian ganglion ((Van Rompaey J, Bush C, Khabbaz E, Vender J, Panizza B, Solares CA. What is the
Best Route to the Meckel Cave? Anatomical Comparison between the Endoscopic
Endonasal Approach and a Lateral Approach. J Neurol Surg B Skull Base. 2013
Dec;74(6):331-6. doi: 10.1055/s-0033-1342989. Epub 2013 Apr 5. PubMed PMID:
24436933.
)).