The glossopharyngeal nerve (GPN) is a seldom thought about cranial nerve in imaging interpretation, greatly bereason clinical indicators may reprimary unnoticed, yet likewise as a result of its complex anatomy and inconspicuousness in conventional cross-sectional imaging. In this photographic review, we aim to conduct an extensive review of the GPN anatomy from its beginning in the main nervous system to peripheral taracquire organs. Because the nerve cannot be visualised with traditional imaging examinations for many of its course, we will emphasis on the most appropriate anatomical referrals along the whole GPN pathway, which will be divided into the brain stem, cisternal, cranial base (to which we will certainly include the parasympathetic pathway leaving the major trunk of the GPN at the cranial base) and cervical segments. For that purpose, we will certainly take benefit of cadaveric slices and also dissections, our own developed illustrations and also schemes, and computed tomography (CT) and also magnetic resonance imaging (MRI) cross-sectional imperiods from our hospital’s radiological indevelopment system and also image and also archiving communication mechanism.
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• The glossopharyngeal nerve is one of the most surprise cranial nerves.
• It conveys sensory, visceral, taste, parasympathetic and also motor information.
• Radiologists’ knowledge need to go past the limitations of standard imaging approaches.
• The nerve’s pathmethod involves the brain stem, cisternal, skull base and also cervical segments.
• Systematising anatomical referrals will certainly aid through nerve pathway tracking.
The glossopharyngeal nerve (GPN) or IX cranial nerve is among the a lot of unattended cranial nerves in imaging examinations. It is not portrayed for many of its course and also, as soon as influenced, clinical manifestations are typically not characteristic. In truth, the GPN and also vagus nerve communicate so closely that an isolated GPN dysfeature could not be clinically discriminated if vagus nerve attribute is not impaired <1>, other than in the particular case of glossopharyngeal neuralgia <1,2,3,4,5>. When a cranial nerve injury is suspected, the nerve’s pathmeans must be taken into consideration from the brain stem to the targain organs <3>. In a standard magnetic resonance imaging (MRI), the substantial majority of cranial nerves are generally visible just in a brief segment but are affected by visible diseases. Because of this, by deepening anatomic expertise, radiologists that analyze cross-sectional imperiods have the right to partially get rid of that limitation.
Previous radiological publications have not been especially concentrated on the anatomic relationships of cranial nerves or on the GPN. Those reviews have actually put even more emphasis on illness that may impact the cranial nerves <3, 4, 6,7,8>. For that factor, and also based on an digital poster (EPOS) presented at the 2013 European Congress of Radiology <9>, the aim of this post is to evaluation the GPN from an anatomical suggest of view, based upon schematics, illustrations and cadaveric specimens, and also to identify the anatomical referrals that indicate the route of the nerve in cross-sectional images. The involvement of the GPN’s pathmeans in pathological procedures is past the scope of this anatomical review, and also the reader deserve to find other imaging reports in other places <3, 4, 6,7,8>.
The GPN conveys: (1) sensory afferental fees (retroauricular region), visceral afferental fees (posterior 3rd of the tongue, pharyngeal tonsil, posterior pharynx, middle ear and Eustachian tube) and taste afferents (posterior 3rd of the tongue); (2) parasympathetic affeleas (carotid sinus baroreceptors and carotid body chemoreceptors) and also efferental fees (parotid gland); and (3) motor effeleas (stylopharyngeus muscle) <1, 2, 8,9,10,11,12,13,14,15,16>. It plays a duty in swallowing, which involves a reflex arc that begins at the taste buds situated in the posterior third of the tongue and stimulates the parotid to secrete a perfect amount of saliva liquid for swenabling <1, 16>. It also carries somatosensory information from muscles and also the ear, the pharynx and also tongue mucous, and also information from the carotid sinus <1, 2, 8,9,10,11,12,13,14,15,16>. As such, though isolated involvement is rare, clinical manifestations of a GPN injury might be exterior earache, mild dysphagia and also taste transforms in the posterior 3rd of the tongue; the swpermitting reflex will be changed on the side of the lesion, the uvula will certainly be deviated to the contralateral side and the sensitivity of the pharynx, palate and tongue will be affected. Changes in the amount and quality of saliva might be present because of parotid involvement, and tachycardia carotid sinus dysattribute can be affected; lastly, glossopharyngeal neuralgia, equivalent to trigeminal neuralgia, is an isolated GPN process that occurs very periodically and is qualified by lancinating pain at the base of the tongue and also palate <1,2,3,4>.
The images retrieved and consisted of in this manuscript were got in a multislice spiral computed tomography (CT), GE LightSpeed VCT 64 (Milwaukee, WI, USA) and also a GE Signa HDx 1.5T MRI scanner (Milwaukee, WI, USA). All images corresponded to clinical examinations perdeveloped according to our conventional cranial, skull base and cervical CT and also MRI protocols (Table 1).
Table 1 Clinical computed tomography (CT) and magnetic resonance imaging (MRI) protocols used in the current review
For the objective of systematisation, we will follow the pattern of Policeni and Smoker <3>. According to these authors, the course of the reduced cranial nerves is split right into the brain stem, cisternal, cranial base (to which we will add the parasympathetic pathway leaving the main trunk of the GPN at the cranial base) and also cervical segments, which, in this instance, is practically diminished to the suprahyoid compartment <4>.
Origin in the brain stem
The GPN and vagus nerve are blended nerves that contain motor, branchial, sensory and also autonomic fibres <16>. Both nerves have actually a widespread beginning in the top medulla oblongata and also share three nuclei: the motor, the parasympathetic and also the special sensory nuclei. In addition, they convey basic sensory indevelopment right into the spinal trigeminal tract <1,2,3, 8, 11, 15,16,17>. Briefly, the motor nucleus requires the top end of the nucleus ambiguous and also innervates the stylopharyngeus muscle. The reduced salivary nucleus sends efferent fibres to the parotid gland. General cutaneous and also visceral sensory indevelopment travels through the GPN, joins the spinal trigeminal tract and ends in the spinal trigeminal nucleus. Finally, the one-of-a-kind sensory nucleus is the solitary tract or gustatory nucleus. It receives taste sensation fibres with the solitary tract. The nucleus of the solitary tract also receives afferent impulses from the carotid sinus via the GPN <1,2,3, 7, 8, 10, 13, 15,16,17>. All nuclei are located behind the inferior olivary nucleus (Fig. 1).
Schematic representation of the glossopharyngeal nerve. a Transversal area of the medulla oblongata at the level of the inferior olivary nucleus. Efferent nuclei: nucleus ambiguous (1) and inferior salivatory nucleus (2); afferent nuclei: solitary nucleus (3) and also sensitive trigeminal nucleus (4). Other relevant structures: dorsal motor nucleus of the vagus nerve (5), pyramidal tract (6) and also hypoglossal nerve (7). b Schematic drawing of the reduced cranial nerves representing their shared relationships and also course from the brain stem to the cranial departure. 1: spinal nerve; 2: glossopharyngeal nerve; 3: vagus nerve; 4: hypoglossal nerve; P: pons; O: inferior olidiffer nucleus; Py: pyramid; C1: atlas; OB: occipital bone. The hypoglossal nerve exits the cranium via the anterior condylar canal; the glossopharyngeal, vagus and also spinal nerves leave the cranium alengthy the jugular foramen. *Glossopharyngeal nerve nodes; black dotted line: retro-olivary groove wright here the glossopharyngeal nerve exits the medulla oblongata via the vagus and spinal nerves. The white dotted line draws the groove between the pyramid and the inferior olivary nucleus, where the hypoglossal nerve exits the brain stem. c, d Upper medulla oblongata as regarded from below. Micrographic slice showing the glossopharyngeal nerve nuclei (c) and also axial T2-weighted brain MRI at the very same level (d). In the anatomical slice (Nissl stain), left nuclei are circumscribed by dotted lines. All nuclei are behind the retro-olidiffer groove (rog). The nerve’s pathmeans is stood for on the appropriate side of the sample, between the retro-olidiffer nucleus and also the inferior cerebellar peduncle (icp). Colours as in a (the white dotted circle encloses the solitary tract)
Brain stem leave and cisternal segment
The GPN emerges in the cerebellomedullary cistern from the medulla oblongata immediately below the bulbopontine sulcus at the level of the retro-olive groove, between the inferior olidiffer nucleus and also the inferior cerebellar peduncle <7, 8, 10> (Fig. 1). At this level, it is immediately over the vagus and spinal nerves (Fig. 2). Within the cistern, the three nerves rest on the posterior margin of the jugular tubercle of the occipital bone (Figs. 2 and also 3), crossing laterally close to the anterior and inferior margin of the flocculus and also the choroid plexus protruding from the fourth ventricle (Fig. 3). When it arrives at the skull base, the GPN enters an exclusive cranial exit close to the peak of the jugular foraguys <10, 13, 14> (Fig. 2). The cranial nerves are visible in the cistern with MRI <4, 15, 18, 19> however not with CT, so the cerebellar flocculus, the choroid plexus and also the jugular tubercle come to be crucial anatomical referrals.
The glossopharyngeal nerve (gpn), cisternal percent. a Schematic illustration of a transversal slice at the level of the medulla oblongata (view from above). The gpn exits the medulla at the retro-olidiffer groove (rog) and crosses through the cerebellomedullary cistern to the jugular foraguys. Within the cistern, it lays listed below and also in front of the choroid plexus (cp) of the fourth ventricle and the cerebellar flocculus (F). The glossopharyngeal nerve exits the skull medial and also anterior to the jugular spine (*). At that level, it is closely concerned the inferior petrosal sinus (ips). The glossopharyngeal nerve crosses first over the sinus to be anterior to the sinus at the extracranial verge of the jugular foramales, posterior to the inner carotid artery. ctn: caroticotympanic or Jacobson nerve; ica: inner carotid artery; jb: jugular bulb; mo: medulla oblongata; O: inferior olivary nucleus; P: Pons; Py: pyramid; ttm: tensor tympani muscle; va: vertebral arteries. b Skull base, view from inside. The reduced cranial nerves have a close relationship via the jugular tubercle (jt). The glossopharyngeal nerve (represented by the dotted black arrow) exits with the pars nervosa of the jugular foraguys, split from the pars vascularis (pv) by the jugular spine (js). cl: clivus; fm: foramales magnum; st: sella turcica; arrowheads: internal auditory meatus
a Axial fast spin-echo T2-weighted brain MRI at the level of the medulla oblongata. The picture mirrors the reduced cranial nerves (lcn) passing by the flocculus (F), the choroid plexus (cp) outside the fourth ventricle (*) and the jugular tubercle (jt) as they technique the cochlear aqueduct (ca); O: inferior olidiffer nucleus; Py: pyramid. b Axial non-intensified brain CT shave the right to, brain window. The flocculus (F) and also the choroid plexus (cp) are reliable references to recognize the place of the adjacent glossopharyngeal nerve
The jugular foraguys and also parasympathetic segment
The cochlear aqueduct, opening just over the GPN entrance in the jugular foramen <14, 15, 19,20,21>, is the initially anatomical reference (Figs. 3 and 4). In the jugular foramen, the GPN runs with the anteromedial portion or pars nervosa (petrosal fossula), separated from the posterolateral percentage or pars vascularis (departure for the vagus and spinal nerves and the internal jugular vein) by the jugular spine (Fig. 2) and a fibrous septum (petro-occipital ligament), which is sometimes ossified <3, 6, 8, 13, 14>. At the entrance to the foramales, the GPN, vagus and also spinal nerves are initially arranged in an obliquely posteroanterior-lateromedial circulation, between the jugular bulb (posterolateral) and the inferior petrosal sinus (anteromedial) <21> (Fig. 2). Once at the exit of the jugular foramales, the GPN is mainly in front of the inferior petrosal sinus prior to draining right into the interior jugular vein <6, 20, 21> (Figs. 2 and 5). Still within the foramales, the GPN reflects two focal expansions or nodes <11> (Fig. 1), which are normally not visible in sectional high-resolution clinical images at 1.5T MRI <18> yet have actually been observed through 3T MRI <21>. The premium node conveys general sensitive information and also is situated beside the opening of the cochlear aqueduct <21>. The lower node (Andersch node) handles the visceral sensory, gustatory and carotid <6, 16> innervations, and also is located approximately 3 mm listed below <21>.
The glossopharyngeal nerve at the jugular foramales. a Coronal T2-weighted brain MRI at the level of the jugular foramen (jf). The picture mirrors the partnership in between the cochlear aqueduct (ca) above, and also the jugular foraguys and also jugular tubercle (jt) listed below. b Skull base CT scan; coronal rebuilding and construction of the right temporal bone, bone home window. The picture mirrors the inferior tympanic canaliculus (itc) for the inferior tympanic or Jacobson’s nerve at the jugular spine. ca: cochlear aqueduct; pn: pars nervosa
The glossopharyngeal nerve (gpn) at the jugular foramen. a Cadaveric area at the level of the skull base; check out from below. The glossopharyngeal nerve exits the skull close to the inferior petrosal sinus (ips), the interior carotid artery (ica) and the jugular vein (jv). jb: jugular bulb. b Corresponding axial neck CT sdeserve to at the extracranial verge of the jugular foramen; best tempdental bone, soft tproblems window. The glossopharyngeal nerve is stood for through a yellow dot
The tympanic nerve or Jacobchild nerve leaves the GPN from the reduced node <10,11,12,13,14>. Fibres of the GPN course through this nerve and have a lengthy cranial and parapharyngeal course, jumping from cranial nerve VII (the facial nerve) to cranial nerve V (the trigeminal nerve), and targeting the parotid gland lastly. The first anatomical recommendation for the Jacobboy nerve is the inlet of the reduced tympanic canaliculus in the jugular spine, which enters just once leaving the GPN <3, 6> and via which it reaches the medial wevery one of the tympanic cavity at the level of the cochlear promontory <7, 14, 22> (Figs. 2, 4 and also 6). Inside the tympanic cavity, the nerve develops a submucosal plexus that conveys sensitive indevelopment from the middle ear mucosa, antrum, mastoid air cells and also Eustachian tube <3, 8, 10, 13,14,15>. At the level of the tendon of the tensor tympani muscle, it provides off a small nerve branch (deep good petrosal nerve) that will bind the lesser superficial petrosal nerve coming from the geniculate ganglion of the facial nerve <6, 11, 12, 23>. The course of the resultant nerve (the lesser petrosal nerve) can be complied with by identifying the geniculate ganglion and also the ducts in front, till the nerve enters the middle cranial fossa with the accessory hiatus, lateral to the leave of the better petrosal nerve, which exits through the fallopian hiatus <10,11,12> (Fig. 6).
The glossopharyngeal nerve (gpn) and the tympanic nerve of Jacobboy. a Skull base CT scan; coronal reconstruction of the appropriate temporal bone, bone home window. Once showing up at the tympanic cavity at the level of the promontory (p), the tympanic nerve creates a submucous plexus within the middle ear consisting of the mastoid antrum and Eustachian tube. At the level of the tendon (ttmt) of the tensor tympani muscle (ttm), a branch of the tympanic plexus exits the cavity through a little duct and also courses forward beside the facial nerve (fn2); brief white arrow: malleus; co: cochlea. b Skull base axial CT scan; ideal tempdental bone, bone home window. The glossopharyngeal nerve fibres will departure the petrosal bone through the accessory hiatus (ah) after joining the lesser petrosal nerve of the facial nerve. fh: fallopian hiatus. c Schematic drawing of the best infratemporal fossa, check out from inside. Glossopharyngeal nerve relationships via the facial (VII) and trigeminal (V) nerves. The lower illustration represents a thorough watch of the area of interemainder (daburned rectangle). The deep good petrosal nerve (dotted arrow) comes up from the tympanic plexus at the level of the tendon of the tensor tympani muscle (ttmt) to merge through the lesser superficial pretrosal nerve coming from the geniculate ganglion (gg) of the facial nerve. The resulting nerve exits the petrosal bone (pb) to the middle cranial fossa at the level of the accessory hiatus (white arrowhead). The hiatus is situated close and lateral to the fallopian hiatus (babsence arrowhead), via which the higher petrosal nerve enters right into the skull. atn: auriculotempdental nerve; ct: chorda tympani; eca: external carotid artery; mpm: medial pterygoid muscle; mma: middle meningeal artery; pg: parotid gland; tc: tympanic cavity; V1: initially trigeminal nerve branch; V2: second trigeminal nerve branch; V3: third trigeminal nerve branch; *Otic ganglion; dashed red circle: foramen ovale. d Skull base regarded from inside. The image shows the fallopian hiatus (fh) and also the accessory hiatus (ah) on the right side, as well as the foraguys spinoamount (1), foramales ovale (2) and sphenopetrosal fiscertain (3), through which the lesser petrosal nerve that consists of the glossopharyngeal nerve fibres might exit the cranium. acf: anterior cranial fossa; cl: clivus; fl: foraguys lacerum; fm: foraguys magnum; mcf: middle cranial fossa; pcf: posterior cranial fossa; st: sella turcica
Once in the middle cranial fossa, it crosses forward and also medially to leave the skull variably via different exits: the foraguys spinosum, foramales ovale, innominate canaliculus (situated in between these 2 foramen) or the sphenopetrosal junction <11, 23> (Figs. 6 and 7). Immediately below the skull, the GPN fibres synapse in the otic ganglion, medial to the mandibular nerve and also simply under the foramales ovale <10,11,12,13> (Fig. 7). The GPN postganglionic fibres leave the otic ganglion with the auriculotemporal branch of the trigeminal nerve. Now, the reference is the line that connects the mandibular nerve through the middle meningeal artery. The auriculotemporal nerve embraces the artery and then goes ago with the parapharyngeal space medial to the lateral pterygoid muscle first and the neck of the mandibular condyle later, to reach the deep lobe of the parotid gland also, providing it with parasympathetic innervation <8, 10, 11, 14, 22> (Fig. 7).
The glossopharyngeal nerve. a Skull base axial CT scan; appropriate tempdental bone, bone home window. The image shows the foraguys ovale, the foramales spinosum, the canaliculus innominatus (ci) of Arnold and the spheno-tempdental junction, every one of which are feasible leave pathmethods of the lesser petrosal nerve. b Coronal quick spin-echo contrast-amplified T1-weighted brain MRI, left side skull base. The images display the connection between the foramales ovale (fo) and the V3 mandibular nerve and also otic ganglion complicated (arrow). et: Eustachian tube; lpm: lateral pterygoid muscle; mpm: medial pterygoid muscle; tvp: tensor veli palatini muscle. c Axial contrast-amplified CT scan of the neck, soft tissues window. Glossopharyngeal nerve and also auriculotemporal nerve. Just listed below the foramales ovale, the glossopharyngeal nerve fibres leave the otic ganglion to merge via the auriculotempdental nerve, a branch of the trigeminal nerve (the nerve pathmethod is stood for by dashed yellow lines). Then, the nerve travels posteriorly in the parapharyngeal space to adopt the middle meningeal artery (mma), crosses alengthy the medial edge of the condylar apophysis of the mandible (cam) and also enters the parotid gland also (pg). lpm: lateral pterygoid muscle; ms: maxillary sinus
Immediately after leaving the jugular foramen, the GPN is located medial to the interior jugular vein and also behind the interior carotid artery (Figs. 5 and also 8). Now it is situated in the retro-styloid or carotid room <4, 24>. When proceeding dvery own the neck, the GPN initially has actually the same vascular relationships. The styloid procedure, the a lot of lateral reference at this level, is likewise a helpful mark <10, 12>. At the level of the C1 transverse process, the nerve goes roughly the carotid artery laterally and also descends behind the styloid process and also the stylopharyngeus muscle <14> (Fig. 8). When it crosses between the inner carotid artery and the interior jugular vein, the GPN provides off the carotid sinus and carotid body nerve (Hering’s nerve), which descends along the anterior wall of the inner carotid artery <11> (Fig. 9).
The glossopharyngeal nerve (gpn), cervical percentage. a Schematic drawing of the glossopharyngeal nerve as soon as leaving the left jugular foramen. The glossopharyngeal nerve is situated medial to the interior jugular vein (ijv) and also behind the interior carotid artery (ica) in the carotid area. The styloid process (sp) is the many lateral referral at this point. At the level of the first cervical vertebra (C1), the glossopharyngeal nerve surrounds the artery laterally and also descends in between the styloid procedure and stylopharyngeus muscle (spm). scm: sternocleidomastoid muscle; sgm: styloglossus muscle; shl: stylohyoid ligament; mp: mastoid process: sn: spinal nerve; vn: vagus nerve. b Axial contrast-enhanced CT sdeserve to of the neck, right side, at the level of the first cervical vertebra lateral process (C1lp); soft tproblems home window. At this suggest, the glossopharyngeal nerve (arrowhead) is located between the internal carotid artery anteriorly and the interior jugular vein behind. The styloid procedure is currently in front of the glossopharyngeal nerve as it transforms around the lateral side of the internal carotid artery to reach the dorsal facet of the stylopharyngeus muscle. At this suggest, Hering’s nerve leaves the glossopharyngeal nerve to go down to the carotid body along the anterior aspect of the internal carotid artery
The glossopharyngeal nerve, cervical portion. a Schematic illustrations that depict the glossopharyngeal nerve at the styloid pyramid and also its oropharynx finish. Once the Hering’s nerve (hn) has left the IX cranial nerve, the glossopharyngeal nerve enters a muscular tripod that consists of three styloid muscles and a fascia (shaded in green): the styloid pyramid. Within the pyramid, the glossopharyngeal nerve (arrowhead) commonly runs in a triangular airplane restricted by the facial artery (*), the exterior carotid artery (**) and the styloglossus muscle (sgm). When the stylopharyngeus muscle merges through the constrictor muscles, the nerve enters the oropharynx and also, ultimately, courses deep to the hyoglossus muscle (hgm). hb: hyoid bone; lc: laryngeal cartilage; shm: stylohyoid muscle; t: tongue. b Sagittal quick flair T1-weighted MRI centred at the skull base. Arrows: internal carotid artery; eca: exterior carotid artery; fa: facial artery; the dotted yellow line represents the supposed pathmethod of the glossopharyngeal nerve
Once the GPN is anterior to the vascular frameworks, it leaves the close partnership through the inner carotid artery roughly at the level of the soft palate <24> and also runs behind the styloid muscles (stylohyoid, styloglossus, stylopharyngeus) (Fig. 10). These muscles develop a tripod that will be the reference until the nerve enters the oropharynx, especially the medial (stylopharyngeus) and the anterior (styloglossus) muscles. The styloid muscles are surrounded by a fibrous fascia (styloid diaphragm); muscles and also fascia kind the styloid pyramid <14> (Fig. 9). The GPN surrounds the external side of the stylopharyngeus muscle to reach its anterior surface inside the pyramid <11>. In this course, the GPN gives motor innervation to the muscle <14, 25, 26>. Once within the pyramid, the the majority of prevalent place of the GPN is in a triangle, in which the posterior margin is the exterior carotid artery, the lower one is the facial artery and the anterior one is the styloglossus muscle <27> (Fig. 9). However before, this reference appears not to be suitable for the prevalent axial slices, in which the long axis of the styloid pyramid location could be an easier anatomical key point (Fig. 10).
Cervical percent of the glossopharyngeal nerve. a Axial contrast-amplified CT scan of the neck, appropriate side, soft tproblems home window. The dotted yellow line draws the borders of the styloid pyramid. 1: styloglossus muscle; 2: stylopharyngeus muscle; 3: stylohyoid muscle; 4: outside carotid artery; cm: constrictor muscles. The dotted white arrow represents the long axis of the styloid pyramid as a referral of the gpn pathmeans. dmp: posterior belly of the digastric muscle; m: mandible. b Axial T2-weighted MRI of the neck, ideal side, at the level of the intermediate tendon of the digastric muscle (dmt). The slice over the level of the tendon is an excellent recommendation for the enattempt suggest of the glossopharyngeal nerve in the pharynx. mhm: mylohyoid muscle
At approximately the suggest where the stylopharyngeus muscle merges through the constrictor muscles, the GPN enters the pharynx between the upper and also middle constrictors <14>. At this point, the stylopharyngeus and also hyoglossus muscles sepaprice the hypoglossal nerve (lateral) from the GPN (medial). This circumstance occurs automatically above the level of the intermediate tendon of the digastric muscle <14> (Fig. 10).
Once in the pharynx, the GPN splits into pharyngeal branches, which add to the pharyngeal plexus of the vagus, and also the lingual branch <4, 6, 10, 14, 25>. The referrals of the lingual branch are the reduced edge of the palatine tonsil (palatoglossus and also styloglossus muscles) and the hyoglossus muscle. The lingual branch reaches the tongue medial to the hyoglossus muscle to innervate the posterior third of the tongue <6, 11> (Fig. 10).
All anatomic references are summarised in Fig. 11.
Rundown of the anatomic referrals of the glossopharyngeal nerve in the cross-sectional typical clinical images
Muscle denervation can be the most visible authorize of neural injury, particularly in larger muscles <5, 28, 29>. However, the GPN only innervates the tiny stylopharyngeus muscle, for which no cases of atrophy have been reported <5, 28>. It additionally contributes to the pharyngeal plexus of the vagus nerve, which provides the palatoglossus and palatopharyngeus muscles, the middle and also upper constrictors, and the levator muscle of the soft palate <5>. Thus, secondary alters in cross-sectional imeras because of GPN denervation cannot be separated from those resulted in by vagus nerve injuries (Fig. 11). Imaging functions are qualified by the soft palate descent at the side of the lesion, a deviated uvula to the opposite side and muscle asymmetries at the level of the torus tubarius and constrictor muscles <1, 26, 28>. Functional parotid gland changes might be unnoticed, as the various other salivary glands remain uninfluenced <1>. More debatable is the possibility of additional gland atrophy after denervation. Parotid atrophy has actually been reported in situations of chronic trigeminal denervation, as the auriculotempdental nerve conveys the gland also innervations <30>. Though we found no previous articles on parotid gland also atrophy concerned lesions affecting the GPN pathmeans, tympanic neurectomies were reported to display that atrophy <31> and also the radiologist should consider this possibility (Fig. 12).
Glossopharyngeal nerve dysattribute. Low cranial nerves palsy. a Coronal rapid spin-echo T1-weighted MRI of the neck. A slightly hypointense mass eroding the ideal jugular foramales (arrow) was demonstrated to be a glomus jugulare paraganglioma. b Coronal rapid spin-echo T1-weighted MRI of the neck. The normal stylopharyngeus muscle (arrowhead) on the left and also its partnership through the exterior carotid artery (eca) aid to recognise the muscle atrophy on the appropriate side. Stylopharyngeus muscle atrophy is just one of the few specific imaging indications of glossopharyngeal nerve dysattribute. c Axial quick spin-echo T1-weighted MRI of the neck. An asymmetric oropharyngeal luguys due to a descfinishing soft palate on the right (arrow) and constrictor muscle atrophy (the arrowhead points to the normal muscles on the left). These are signs of vagus nerve dysattribute, which is usually linked with glossopharyngeal nerve changes. d Axial quick spin-echo T1-weighted MRI of the neck. The uvula (arrow) is disput to the left side (the dotted midline has actually been attracted to emphasise that displacement), which is the other typical sign of vagus nerve palsy. Intriguingly, this patient likewise showed a best parotid gland also (pg) atrophy, which could be concerned the glossopharyngeal nerve dysattribute. Also note the fat replacement of the appropriate side of the tongue due to hypoglossal nerve palsy
The novelty of this short article is the certain emphasis on the glossopharyngeal nerve (GPN) in cross-sectional imaging, which systematises the anatomical relationships of the primary trunk and also its branches. It will help radiologists achieve insights into a cranial nerve that, unlike many type of of its countercomponents, remains beyond the observer’s attention because of its inconspicuous clinical indicators and also scarce visibility in normal and pathological clinical imeras.
The manumanuscript comes from an digital poster presented as an educational exhibit throughout the European Congress of Radiology (ECR) organized in Vienna in March 2013, wbelow it was distinguiburned with a cum laude award. The poster is easily accessible in the EPOS database through the complying with link: https://doi.org/10.1594/ecr2013/C-1419.
Radiology Department, College General Hospital JM Morales Meseguer, University of Murcia, Murcia, Spain
José María García Santos, Sandra Sánchez Jiménez & Marta Tovar Pérez
Radiology Department, University General Hospital JM Universitario Morales Meseguer, C/ Marqués de los Velez s/n, 30008, Murcia, Spain
José María García Santos
Radiology Department, University Hospital Santa Lucía, University of Murcia, Cartagena (Murcia), Spain
Sandra Sánchez Jiménez & Marta Tovar Pérez
Department of Anatomy, Murcia School of Medicine, University of Murcia, Murcia, Spain
Matilde Moreno Cascales & Miguel A. Fernández-Villacañas Marín
Radiology Department, Hospital Barros Luco Trudeau, Santiearlier de Chile, Chile
Javier Lailhaautomobile Marty
Correspondence to José María García Santos.
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García Santos, J.M., Sánchez Jiménez, S., Tovar Pérez, M. et al. Tracking the glossopharyngeal nerve pathway through anatomical references in cross-sectional imaging techniques: a pictorial review. Insights Imaging 9, 559–569 (2018). https://doi.org/10.1007/s13244-018-0630-5
Received: 04 October 2017
Revised: 09 April 2018
Accepted: 16 April 2018
Published: 13 June 2018
Issue Date: August 2018
KeywordsAnatomyCranial nervesCentral nervous systemTomography, X-ray computedMagnetic resonance imaging
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