Cranial Nerves IX, X, XI, XII PDF

Cranial Nerves IX, X, XI, XII Dr. A. Aktar Cranial Nerve IX - Glossopharyngeal • Sensory, motor, parasympathetic Nuclei: • Nucleus ambiguus: Motor • Inf. salivatory nucleus: PS • Solitary tract nucleus: Taste • Exit brain stem: Medulla • Leaves skull: Jugular foramen • 2 sensory ganglia: s...

Cranial Nerves IX, X, XI, XII Dr. A. Aktar Cranial Nerve IX - Glossopharyngeal • Sensory, motor, parasympathetic Nuclei: • Nucleus ambiguus: Motor • Inf. salivatory nucleus: PS • Solitary tract nucleus: Taste • Exit brain stem: Medulla • Leaves skull: Jugular foramen • 2 sensory ganglia: superior ganglion + inferior ganglion • At level of jugular foramen Cranial Nerve IX - Glossopharyngeal Jugular foramen: Formed anteriorly by petrous portion of temporal bone & posteriorly by occipital bone Glossopharyngeal N. – In Jugular Foramen • Travels together w/CN X & XI • Btwn int jugular v. & int carotid a. • Descends below styloid process Cranial Nerve IX - Glossopharyngeal Types of Fibers General sensory • Post. 1/3rd part of tongue, soft palate, upper pharynx, palatine tonsils, internal surface of tympanic membrane • Cell bodies in either sup. or inf. glossopharyngeal ganglion • Small patch on post. part of concha of auricle • Fibers travel within auricular branch of vagus n. • Carotid sinus & carotid body (communicates w/vagus n.) • General sensory fibers synapse in caudal spinal nucleus of CN V Taste • Post 1/3 of tongue (post-sulcal part) • Inf. glossopharyngeal ganglion → carries to solitary tract nucleus (gustatory part) Cranial Nerve IX - Glossopharyngeal Types of Fibers Branchial Motor • Stylopharyngeus m. • Originate from cranial part of nucleus ambiguus • Fibers don’t synapse on ganglia in jugular foramen Parasympathetic • Parotid gland via otic ganglion (& hitchiking on auriculotemporal n.) • Originate in inferior salivatory nucleus Cranial Nerve IX - Glossopharyngeal Branches • Tympanic • Stylopharyngeal • Tonsillar • Nerve to carotid sinus • Branches to post. 1/3rd of tongue • Lingual branches • A communicating branch to Vagus n. Cranial Nerve IX - Glossopharyngeal B Cranial Nerve X - Vagus Vagrant: • A person without a settled home or regular work who wanders from place to place and lives by begging • A wanderer Cranial Nerve X - Vagus • Sensory, motor, parasympathetic Nuclei: • Nucleus ambiguus: Branchial motor & preganglionic PS to heart • Dorsal nucleus of vagus: PS • Solitary tract nucleus: Taste & visceral afferents • Arises as a group of rootlets • Exit brain stem: Medulla • Leaves skull: Jugular foramen • Has 2 sensory ganglia: Superior ganglion (jugular) + inferior ganglion (nodose) • Within or immediately outside jugular foramen • Contain cell bodies of sensory neurons Cranial Nerve X - Vagus Superior Ganglion of Vagus (Jugular Ganglion ) • Located in middle part of jugular foramen • Contains sensory neuron cell bodies • Ext. auditory meatus (auricular branch), cranial meninges (meningeal branch) & ext. surface of tympanic membrane • Central fibers synapse in trigeminal nerve nuclei Inferior Ganglion of Vagus (Nodose Ganglion) • Located in height of transverse process of C1 General Sensory Cranial Nerve X - Vagus • Larynx, laryngopharnyx, deeper part of auricle, part of ext acoustic meatus, dura in post cranial fossa • Solitary tract & nucleus General Visceral Sensory • Aortic arch chemoreceptors and barorecetors, esophagus, bronchi, lungs, heart, abdominal organs from fore-gut & mid-gut Special Sensory • Taste from epiglottis & pharynx Parasympathetic • Smooth muscles & glands of pharynx, larynx, thoracic & abdominal viscera from fore-gut up to hind-gut Branchial Motor • Palatoglossus m. • Muscles of soft palate (except tensor veli palatini) • Pharynx (sup., middle & inf. pharyngeal constrictor mm., palatopharyngeus m., salpingopharyngeus m.) (except stylopharyngeus) • Larynx Cranial Nerve X - Vagus Course & Branches of CN X in Neck Region • In neck courses btwn int carotid a. & int. jugular v. R carotid sheath Cranial Nerve X - Vagus Recurrent Laryngeal Nerve • A recurrent course, moving in the opposite direction to the nerve it branches from • Supplies all intrinsic muscles of larynx, w/ exception of cricothyroid m. (superior laryngeal branch) • Course different on R & L • L loops under aortic arch • R loops under R subclavian a. Cranial Nerve XI - Accessory • Motor only • Sternocleidomastoid & trapezius muscles Nuclei: • Spinal root: Spinal nucleus of accessory n. Cranial Nerve XI - Accessory • Arise from motor neurons in upper 5 cervical segments of spinal cord • Fibers leave lateral surface of cord • Fibers ascend, unite & enter skull thru foramen magnum • Continue thru post cranial fossa • Leave skull from jugular foramen • Descends down neck to innervate SCM & trapezius mm. Cranial Nerve XII - Hypoglossal • GSE • Motor only • All intrinsic & most extrinsic muscles of tongue • Extrinsics: Hyoglossus, styloglossus, genioglossus mm • Plus gives a branch to ansa cervicalis (descending branch) Cranial Nerve XII - Hypoglossal • Arises ant surface of medulla as several rootlets • Exit thru hypoglossal canal Cranial Nerve XII - Hypoglossal • Nucleus of hypoglossal n. in medulla • Close to midline & extends length of medulla