02/11/2020 1 Cranial nerves: normal anatomy and imaging Head&Neck Neuroradiology 1st Cycle Module 1 4th‐6th November 2020 Sofie Van Cauter, MD PhD 12 pairs of cranial nerves Motor and sensory functions of the head and neck Purely sensory (afferent): I: olfaction II: vision VIII: hearing ‐ balance Purely motor (efferent): III: Rectus muscles (exc. lateral) and inferior oblique mucles IV: Superior oblique muscle VI: Lateral rectus muscle XI: Sternocleidomastoid, trapezius muscles XII: Intrinsic and extrinsic tongue muscles (exc. palatoglossus, mylohyoid and digastric (ant belly)) Mixed V: Sensory facial region ‐ Motor masticator muscles, tensor palatini/tympani m, mylohyoid and digastric (ant belly) m. VII: Taste ant 2/3 tongue‐ Parasympathic lacrimal glands submandibular sublingual glands ‐ Motor facial muscles IX: Taste post 1/3 tongue ‐ Sensory middle ear pharynx ‐ Parasympathic parotid ‐ Motor m. stylopharyngeus ‐ Viscerosensory carotid body X: Taste epiglottis ‐ Sensory external ear/ auditory canal/eardrum‐ Parasympathic H&N and ThorAbd ‐ Motor palatoglossus, constrictor pharynx, larynx, uvula‐ Viscerosensory larynx, oesophagus, trachea, ThorAbd organs Cavernous sinus Jugular foramen Nuclei not in the brainstem Derivatives of the forebrain Myelination not by Schwann cells MRI High contrast and spatial resolution 3D GE sequences! End organ muscles! CT Inferior to MRI Trauma Intraosseous segments of cranial nerves Bony foramina Romano et al. Insights into Imaging 2019 1 2 3 4
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Nuclei not in the brainstemDerivatives of the forebrain
Myelination not by Schwann cells
MRI
High contrast and spatial resolution
3D GE sequences!
End organ muscles!
CT Inferior to MRI
Trauma
Intraosseous segments of cranial nervesBony foramina
Romano et al. Insights into Imaging 2019
1 2
3 4
02/11/2020
2
• Sensitive nerve /extension of the brain – olfactory stimuli
• Shortest cranial nerve – enveloped by ensheating glia
: Olfactory fossa
Nasal epithelium (2,5 cm2 in roof of the nose/septum)Bipolar olfactory receptor cells (first order neurons) Not visible on MRI or CTTransethmoidal segment
Jugular ForamenOpening on the skull base between the occipital and the temporal bone
CE –CISS sequences
Linn et al, AJNR 30: 34-41, 2009
Jugular spine
Pars nervosa n. IX
Pars vascularis n. X and n. XI
jugular foramen
1. ICA2. Inferior petrosal sinus3. Sigmoid sinus
N. IX
N. X ‐ XIN. X ‐ XI
N. IXJugular spine
Hypoglossal nerve
Medulal Oblongata
Preolivary sulcusMultiple rootlets
Skull BaseHypoglossal canal
Intra‐axial segment
Cisternal segment
Extracranial segment
Carotid space – posterior aspectExtrinsic tongue muscles
Hypoglossal nerve
Hypoglossal canalJugular foramen
Jugular tubercle
coronal transversal
“ Dans les champs de l’observation, le hasard ne favorise ques les esprits préparés”“ Where observation is concerned, chance favours only the prepared mind”