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Head and Neck
Published in Bobby Krishnachetty, Abdul Syed, Harriet Scott, Applied Anatomy for the FRCA, 2020
Bobby Krishnachetty, Abdul Syed, Harriet Scott
Course Sensory fibres decussate, emerging at the upper pons as a large sensory and smaller motor root.Trigeminal ganglion (also known as Gasserian or semilunar ganglion) is a crescent-shaped swelling formed by the sensory fibres situated at the apex of the petrous temporal bone. The ganglion is surrounded superiorly by the temporal lobe, medially by the internal carotid artery and cavernous sinus, and inferiorly lies the motor root.The motor fibres bypass the ganglion and join the mandibular division.
Skin infections
Published in Ronald Marks, Richard Motley, Common Skin Diseases, 2019
The disorder often starts with paraesthesiae or pain in the distribution of one or more dermatomes. Involvement of one of the branches of the trigeminal ganglion, with lesions in the distribution of the maxillary, mandibular or ophthalmic sensory nerves, is common, as is involvement of dermatomes of the cervical and thoracic regions. Lesions are confined to the skin innervated by the dorsal primary root(s) infected (Fig. 4.17), although there may be a small number of lesions elsewhere. About 25–30 per cent of patients with shingles continue to have pain and paraesthesiae in the area long after the skin lesions have disappeared.
The pathophysiology of primary headache
Published in Stephen D. Silberstein, Richard B. Upton, Peter J. Goadsby, Headache in Clinical Practice, 2018
Stephen D. Silberstein, Richard B. Upton, Peter J. Goadsby
The trigeminal innervation of pain-producing intracranial structures surrounding the large cerebral vessels, plal vessels, large venous sinuses, and dura mater is a plexus of largely unmyelinated fibres that arise from the trigeminal ganglion and in the posterior fossa from the upper cervical dorsal roots.39–40 Tracing studies have shown that fibres innervating cerebral vessels arise from within the trigeminal ganglion from neurons that contain substance P and calcitonin generelated peptide (CGRP).41 Substance P and CGRP are released when the trigeminal ganglion is stimulated either in humans or cats.42 The cell bodies in the trigeminal ganglion are pseudo-unipolar neurons that innervate the large cerebral arteries and dura mater and arise from the first or ophthalmic division of the trigeminal nerve. Stimulation of the cranial vessels, such as the superior sagittal sinus, is certainly painful in humans,43,44 and in experimental animals causes cranial release of CGRP.45 Human dural nerves that innervate the cranial vessels largely consist of small-diameter myelinated and unmyelinated fibres that subserve a nociceptive function48,47 (Table 5.1).
Prepontine cisternal routine for intrathecal targeted drug delivery in craniofacial cancer pain treatment: technical note
Published in Drug Delivery, 2022
Haocheng Zhou, Dong Huang, Dingquan Zou, Junjiao Hu, Xinning Li, Yaping Wang
The prepontine cistern is one subarachnoid space located dorsally to the clivus and ventrally to the pons. The prepontine cistern contains two cranial nerves, that is the fifth cranial nerve (trigeminal nerve) and the sixth cranial nerve (abducens nerve). The abducens nerve has been considered to transverse the anterior pontine membrane rather than through the prepontine cistern (Matsuno et al., 1988). The trigeminal nerve leaves the mid-pons anteriorly and then courses across the space of prepontine cistern. Subsequently, the fifth cranial nerve courses through the porus trigeminus and enters the Meckel cave, which forms the trigeminal or Gasserian ganglion. The trigeminal ganglion then separates into ophthalmic, maxillary and mandibular branches, which mainly governs the sensory perception in the region of face and head.
Calcitonin gene-related peptide (CGRP): role in migraine pathophysiology and therapeutic targeting
Published in Expert Opinion on Therapeutic Targets, 2020
Anne-Sophie Wattiez, Levi P. Sowers, Andrew F. Russo
Within the CNS, CGRP and its receptor are present in multiple pathways believed to play a role in migraine pathophysiology [8]. The trigeminal ganglion (located outside of the BBB) projects to the trigeminal nucleus caudalis (TNC) where second-order neurons carry the signals to the posterior thalamic area (PTA). We use PTA as a term to encompass all nuclei in the posterior thalamic area. The PTA appears to be a sensory integration center that is abnormal during migraine. Neurons in the thalamus receive input from the TNC and retinal ganglion cells [36], and several key studies have demonstrated in rodents the importance of the PTA in the development of photophobia and highlight the PTA as a possible center for the integration of light and pain [36–38]. CGRP likely contributes to this pathway as both CGRP and its receptors are present in discrete nuclei of the PTA. This is further supported by a study showing that injection of CGRP into the PTA facilitates neuronal firing [38]. Moreover, somatosensory and nociceptive stimuli from ascending pathways converge on the CGRP-producing neurons of the subparafasicular and intralaminar nuclei [39]. In humans, the posterior thalamus is known to be activated during migraine attacks and has altered functional connectivity with multiple brain regions [40,41]. Taken together, these data suggest that pre- and post-synaptic neuromodulatory actions of CGRP that have been reported in other neural circuits [42], could contribute to a state where the PTA is hypersensitive to sensory stimuli.
The first-line cluster headache medication verapamil alters the circadian period and elicits sex-specific sleep changes in mice
Published in Chronobiology International, 2021
Mark J. Burish, Chorong Han, Kazuaki Mawatari, Marvin Wirianto, Eunju Kim, Kaori Ono, Randika Parakramaweera, Zheng Chen, Seung-Hee Yoo
The hypothalamus and cerebellum are central nervous system structures known to have pronounced circadian oscillations and may be important structures in the pathophysiology of cluster headache (Arkink et al. 2017; Clelland et al. 2014; May et al. 1998; Naegel et al. 2014; Teepker et al. 2012; Yang et al. 2015). The trigeminal ganglion is an important peripheral nervous system structure for cluster headache pain (Jarrar et al. 2003; May et al. 2018; McGeeney 2018), though its circadian oscillations are not well studied. To examine whether verapamil treatment can affect the expression of clock genes in these areas, we measured mRNA expression levels of 10 core clock genes collected at ZT6 and ZT18 from verapamil-treated and control mice (Figure 5). Verapamil altered circadian expression of Clock, Bmal1, Per1, Rev-erbα, and Dbp at ZT6 significantly in the cerebellum from verapamil-treated mice compared to control mice. In the hypothalamus, verapamil altered expression of Bmal1, Per1, and Cry2 at both time points, changed expression of Per2 and Per3 at ZT6, and changed Cry1 expression at ZT18. Furthermore, in the trigeminal ganglion, we found altered mRNA expression of Per3 at both time points, altered mRNA expression of Bmal1 and Per2 at ZT6, and altered mRNA expression of Cry1 at ZT18. Taken together, these results show that verapamil can alter circadian clock gene expression in brain regions and in the trigeminal ganglion. Interestingly, Bmal1 mRNA expression was consistently downregulated by verapamil at ZT6 in all tissues as compared to control.