2/11/2011 The Cranial Nerves & Spinal nerves Departemen Anatomi Fakultas Kedokteran USU Names of cranial nerves • Ⅰ Olfactory nerve • Ⅱ Optic nerve • Ⅲ Oculomotor nerve • Ⅳ Trochlear nerve • Ⅴ Trigeminal nerve • Ⅵ Abducent nerve • Ⅶ Facial nerve • Ⅷ Vestibulocochlear nerve • Ⅸ Glossopharyngeal nerve • Ⅹ Vagus nerve • Ⅺ Accessory nerve • Ⅻ Hypoglossal nerve 1 2/11/2011 Classification of cranial nerves • Sensory cranial nerves : contain only afferent (sensory) fibers – ⅠⅠⅠOlfactory nerve – ⅡⅡⅡOptic nerve – ⅧⅧⅧ Vestibulocochlear nerve • Motor cranial nerves : contain only efferent (motor) fibers – ⅢⅢⅢ Oculomotor nerve – ⅣⅣⅣ Trochlear nerve – ⅥⅥⅥAbducent nerve – ⅪⅪⅪ Accessory nerv – ⅫⅫⅫ Hypoglossal nerve • Mixed nerves : contain both sensory and motor fibers--- – ⅤⅤⅤTrigeminal nerve, – ⅦⅦⅦ Facial nerve, – ⅨⅨⅨGlossopharyngeal nerve – ⅩⅩⅩVagus nerve Sensory cranial nerves N. Location of cell Cranial Terminal Main body and axon exit nuclei action categories ⅠⅠⅠ Olfactory cells Cribrifom Olfactory Smell (SVA) foramina bulb ⅡⅡⅡ Ganglion cells Optic Lateral Vision (SSA) canal geniculate body ⅧⅧⅧ Vestibular Internal Vestibular Equilibri ganglion(SSA) acoustic nuclei um meatus Cochlear Cochlear Hearing ganglion (SSA) nuclei 2 2/11/2011 Olfactory nerve Olfactory mucosa (SVA) → Cribriform foramina → Olfactory bulb Optic nerve Ganglion cell (SSA) → Optic canal → Lateral geniculate body 3 2/11/2011 Vestibulocochlear nerve Vestibular ganglion(SSA) ↘↘↘↗↗↗ Vestibular nuclei Internal acoustic meatus Cochlear ganglion (SSA) ↗↗↗↘↘↘ Cochlear nuclei Motor cranial nerves N. Nucleus of origin and Cranial exit Main action axon categories ⅢⅢⅢ Nucleus of oculomotor Superior orbital Motot to superior, inferior (GSE) fissure and medial recti; inferior obliquus; levator palpebrae superioris Accessory nucleus of Parasympathetic to oculomotor (GVE) sphincter pupillea and ciliary muscl ⅣⅣⅣ Nucleus of trochlear Superior orbital Motor to superior obliquus nerve (GSE) fissure ⅥⅥⅥ Nucleus of abducent Superior orbital Motor to lateral rectus nerve (GSE) fissure ⅪⅪⅪ Nucleus of accessory Jugular foramen Motor to nerve (SVE) sternocleidomastoid and trapezius ⅫⅫⅫ Nucleus of hypoglossal Hypoglossal canal Motot to muscles of nerve( GSE) tongue 4 2/11/2011 Oculomotor nerve • Components – General somatic efferent fibers (GSE) – General visceral efferent fibers (GVE) • Main action －－－supplies – Superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris – Sphincter pupillea and ciliary muscle • Ciliary ganglion: lies between optic nerve and lateral rectus Oculomotor nerve 5 2/11/2011 Accessory nerve Abducent nerve Hypoglossal nerve Hypoglossal nerve 6 2/11/2011 Oculamotor paralysis Abducent nerve injury Mixed cranial nerves 7 2/11/2011 Trigeminal nerve Components of fibers • SVE fibers : originate from motor nucleus of trigeminal nerve, and supply masticatory muscles • GSA fibers : transmit facial sensation to sensory nuclei of trigeminal nerve, the GSA fibers have their cell bodies in trigeminal ganglion, which lies on the apex of petrous part of temporal bone 8 2/11/2011 Branches • Ophthalmic nerve (Ⅴ1, sensory) leave the skull through the superior orbital fissure, to enter orbital cavity • Branches – Frontal nerve: • Supratrochlear nerve • Supraorbital nerve – Lacrimal nerve – Nasociliary nerve Distribution: • Sensation from cerebral dura mater • Visual organ • Mucosa of nose • Skin above the eye and back of nose 9 2/11/2011 Maxillary nerve (Ⅴ2, sensory) • Leave skull through foramen rotundum • Branches – Infraorbital nerve – Zygomatic nerve – Superior alveolar nerve – Pterygopalatine nerve Distribution : • Sensation from cerebral dura mater • Maxillary teeth • Mucosa of nose and mouth • Skin between eye and mouth 10 2/11/2011 Mandibular nerve (Ⅴ3, mixed) • Leave the skull through the foramen ovale to enter the infratemporal fossa • Branches – Auriculotemporal nerve – Buccal nerve – Lingual nerve – Inferior alveolar nerve – Nerve of masticatory muscles 11 2/11/2011 Distribution : • Sensation from cerebral dura mater • Teeth and gum of lower jaw • Mucosa of floor of mouth • Anterior 2/3 of tongue • Skin of auricular and temporal regions and below the mouth • Motor to masticatory muscles, mylohyoid, and anterior belly of digastric Facial nerve ( Ⅶ) Components of fibers • SVE fibers originate from nucleus of facial nerve, and supply facial muscles • GVE fibers derived from superior salivatory nucleus and relayed in pterygopalatine ganglion and submandibular ganglion. The postganglionic fibers supply lacrimal, submandibular and sublingual glands • SVA fiber from taste buds of anterior two-thirds of tongue which cell bodies are in the geniculate ganglion of the facial nerve and end by synapsing with cells of nucleus of solitary tract • GSA fibers from skin of external ear 12 2/11/2011 Course : leaves skull through internal acoustic meatus, facial canal and stylomastoid foramen, it then enters parotid gland where it divides into five branches which supply facial muscles 13 2/11/2011 Branches within the facial canal • Chorda tympani : joins lingual branch of mandibular nerve – To taste buds on anterior two-thirds of tongue – Relayed in submandibular ganglion, the postganglionic fibers supply submandibular and sublingual glands • Greater petrosal nerve : GVE fibers pass to pterygopalatine ganglion and there relayed through the zygomatic and lacrimal nerves to lacrimal gland • Stapedial nerve : to stapedius 14 2/11/2011 Branches outside of facial canal • Temporal • Zygomatic • Buccal • Marginal mandibular • Cervical • Pterygopalatine ganglion : lies in pterygopalatine fossa under maxillary nerve • Submandibular ganglion : lies between lingual nerve and submandibular gland 15 2/11/2011 Injury to the facial nerve Glossopharyngeal nerve ( Ⅸ) Components of fibers • SVE fibers: originate from nucleus ambiguus, and supply stylopharygeus • GVE fibers: arise from inferior salivatory nucleus and ralyed in otic ganglion, the postganglionic fibers supply parotid gland • SVA fibers: arise from the cells of inferior ganglion, the central processes of these cells terminate in nucleus of solitary tract, the peripheral processes supply the taste buds on posterior third of tongue • GVA fibers: visceral sensation from mucosa of posterior third of tongue, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, and end by synapsing with cells of nucleus of solitary tract • GSA fibers: sensation from skin of posterior surface of auricle and 16 2/11/2011 Course : leaves the skull via jugular foramen Branches • Lingual branches : to taste buds and mucosa of posterior third of tongue • Pharyngeal branches : take part in forming the pharyngeal plexus • Tympanic nerve : GVE fibers via tympanic and lesser petrosal nerves to otic ganglion, with postganglionic fibers via auriculotemporal ( Ⅴ3) to parotid gland • Carotid sinus branch : innervations to both carotid sinus and glomus • Others: tonsillar and stylophayngeal branches Otic ganglion : situated just below foramen ovale 17 2/11/2011 Vagus nerve ( Ⅹ) components of fibers • GVE fibers: originate from dorsal nucleus of vagus nerve, synapse in parasympathetic ganglion, short postganglionic fibers innervate cardiac muscles, smooth muscles and glands of viscera • SVE fibers: originate from ambiguus, to muscles of pharynx and larynx • GVA fibers: carry impulse from viscera in neck, thoracic and abdominal cavity to nucleus of solitary tract • GSA fiber: sensation from auricle, external acoustic meatus and cerebral dura mater 18 2/11/2011 Course • Exits the skull from jugular foramen • Descends in the neck in carotid sheath between internal (or common) carotid artery and internal jugular vein Right vagus nerve • Enter thoracic inlet on right side of trachea • Travels downward posterior to right brachiocephalic vein and superior vena cava • Passes posterior to right lung root • Forms posterior esophageal plexus • Forms posterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches 19 2/11/2011 Left vagus nerve • Enter thoracic inlet between left common carotid and left subclavian arteries, posterior to left brachiocephalic vein • Crosses aortic arch where left recurrent laryngeal nerve branches off • Passes posterior to left lung root • Forms anterior esophageal plexus • Forms anterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches Branches in neck • Superior laryngeal nerve : passes down side of pharynx and given rise to – Internal branch , which pierces thyrohyoid membrane to innervates mucous membrane of larynx above fissure of glottis – External branch , which innervates cricothyroid • Cervical cardiac branches : descending to terminate in cardiac plexus • Others: auricular, pharyngeal and meningeal branches 20 2/11/2011 Superior laryngeal nerve Internal branch External branch Branches in thorax • Recurrent laryngeal nerves – Right one hooks around right subclavian artery, left one hooks aortic arch – Both ascend in tracheo-esophageal groove – Nerves enter larynx posterior to cricothyroid joint, the nerve is now called inferior laryngeal nerve – Innervations: laryngeal mucosa below fissure of glottis , all laryngeal laryngeal muscles except cricothyroid • Bronchial and esophageal branches 21 2/11/2011 Branches in abdomen • Anterior and posterior gastric branches – Run close to lesser curvature and innervate anterior and posterior