L29 Last four cranial nerves.pdf

PRO : 1Q : drawing (Sem 1 got ISAQ). L SAQ. 7 : writing oul >1 cmug 2/3 clinical...

PRO : 1Q : drawing (Sem 1 got ISAQ). L SAQ. 7 : writing oul >1 cmug 2/3 clinical - Auto FACULTY OF DENTISTRY ANATOMY DDS YR1 (0109) By: Dr. Maher ([email protected])  ANATOMY LECTURE 30: The last four cranial nerves Learning Outcomes At the end of the lecture, students should be able to: 1. Describe the glossopharyngeal nerve nuclei location, course, type of fibers it carries, areas it supplies and effect of lesion. 2. Describe the vagus nerve nuclei location, course, type of fibers it carries, areas it supplies and effect of lesion. 3. Describe the spinal accessory nerve nuclei location, course, type of fibers it carries, areas it supplies and effect of lesion. 4. Describe the hypoglossal nerve nuclei location, course, type of fibers it carries, areas it supplies and effect of lesion. ANATOMY LECTURE 30: The last four cranial nerves  ANATOMY infundibulum Optic chiasm LECTURE 30: The lastMammillary four cranial body nerves Medulla oblongata – cranial nerves The rootless of the hypoglossal nerve leave the medulla in the groove between the pyramid and olive and. The rootlets of the glossopharyngeal, vagus, and cranial root of accessory Glossopharyngeal leave the medulla in the groove nerve (CN IX) between the olive and inferior cerebellar peduncle vagus nerve (CN X) cranial accessory 4th ventricle (CN XI) inferior pyramid olive cerebellar peduncle Spinal accessory vagus n. Hypoglossal nerve (CN XII) Hypoglossal n. GLOSSOPHARYNGEAL NERVE (CN IX) Location of cell bodies: 1) Nucleus Ambiguus: cell bodies of origin for somatomotor fibers that innervate stylopharyngeus 2) Inferior Salivary Nucleus: cell bodies of origin for visceromotor fibers that are involved in parasympt innervation of the parotid gland entrallya neuf Preganglionic arise from parasymd pregaglionic parasympathetic fibers carried by tympanic branch of CN IX, then fibers will join lesser petrosal nerve  relay at otic ganglion and then carried auriculotemporal nerve  Spina l Central processes from the inferior ganglion of CN IX terminate in: other T 3) Nucleus solitarius – taste fibers from sevel posterior third of tongue, carotid body Liber ne he and carotid sinus. also relay 4) Spinal trigeminal nucleus – general sensory from posterior third of tongue, pharynx, middle ear, auditory tube & mastoid air cells - taste Fibers for post' land will relay a i aferior ganglion which has a cel body  Spina Inferior Ganglion of the l Glossopharyngeal nerve (at the jugular foramen). Peripheral processes carry: 1) special sense (taste) & somatosensory information from the posterior 1/3 of tongue 2) Somatosensory information from the oro- pharynx 3) Somatosensory information from the middle ear, auditory tube & mastoid air cells 4) General viscerosensory information from the carotid body (chemoreception) & carotid sinus (baroreception). 1- carried out by lingual branch 2- pharyngeal branch that combines with the vagus nerve to form the pharyngeal plexus 3- carried out by tympanic branch 4- carried by the carotid sinus nerve  ANATOMY LECTURE 30: The last four cranial nerves Effects of Lesions When a foreign object touches the back of the mouth (oropharynx), it will stimulate the sensory fibers carried by pharyngeal branch of CNIX. The efferent part is carried by vagus nerve  gag reflex. So absent gag reflex is a result pf damaged CNIX. Loss of secretion of parotid gland causing reduction in salivation VAGUS NERVE (CN X) - Contains somatomotor, visceromotor and somatosensory components - Somatomotor innervates skeletal muscles of larynx, pharynx and soft palate - Visceromotor component innervates smooth muscle of the trachea, bronchi gastrointestinal tract to splenic flexure, regulate heart rhythm. - Sensory component innervates laryngeal mucosa, meninges of posterior cranial fossa, external ear, heart and abdominal organs. - General and Special sensory for root of the tongue - Leaves cranial cavity through jugular foramen  ANATOMY LECTURE 30: The last four cranial nerves VAGUS NERVE (CN X) - contains somatomotor, visceromotor and somatosensory components 1) Nucleus Ambiguus: neuronal cell bodies that innervate skeletal muscles including: pharyngeal constrictor muscles, intrinsic muscles of larynx (external laryngeal & recurrent laryngeal nn.), levator veli palatini (soft palate) and palatoglossus, palatopharyngeus, salpingopharyngeus 2) Dorsal Motor Nucleus of the Vagus: first neuronal cell bodies responsible for parasympathetic innervation of smooth muscle of digestive system (to splenic flexure), respiratory system and heart. branch larynx mainly - of vagus ANATOMY LECTURE 30: The last four cranial nerves Spinal trigeminal nucleus  ANATOMY LECTURE 30: The last four cranial nerves Inferior Ganglion of the vagus nerve (nodose ganglion): innervate mucosa of larynx, respiratory system, heart and digestive system. Its central processes (axons) terminate in the 3) nucleus solitarius of brainstem. Superior Ganglion: innervate external auditory meatus, meninges of the posterior cranial fossa and external surface of tympanic membrane. Its central fibers terminate in 4) spinal trigeminal nucleus of brainstem. sanglion ↓ conection body / of cell ANATOMY LECTURE 30: The last four cranial nerves Spinal trigeminal nucleus  ANATOMY LECTURE 30: The last four cranial nerves Effects of Lesions - Hyperactivity of vagus-stomach ulcers; disruption of swallowing, vomiting, and cough reflex - Disruption or loss of carotid sinus reflex - Disruption of normal respiratory functions; loss of taste sensation from root of the tongue - Probable loss of somatosensory sensation from the skin of external ear, tympanic membrane, and root of the tongue (Spinal) Accessory Nerve (CN XI) Location: C1-C5 of spinal cord is in the posterior portion of the anterior (ventral) horn. - fibers leave spinal cord between the posterior (dorsal) and anterior (ventral) roots to enter cranial cavity through foramen magnum. - fibers then exit cranial cavity through the jugular foramen. - innervates the sternocleidomastoid and trapezius. + vagus cranial accessory n. for spinal > -  ANATOMY LECTURE 30: The last four cranial nerves Effect of lesion - Shoulder pain in neck and upper back due to straining of supporting muscles (rhomboids and levator scapulae) with subsequent traction on the brachial plexus. - Limited or loss of sustained abduction of the shoulder.  all muscle of torgue except HYPOGLOSSAL NERVE (CN XII) (supply Palatogloss- Hypoglossal nucleus: 91). neuronal cell bodies for the hypoglossal nerve. - Exits cranial cavity through hypoglossal canal of occipital bone - In neck it loops around occipital artery to enter lateral side of the tongue - innervates: Intrinsic and extrinsic muscles (hyoglossus, styloglossus & genioglossus) of tongue  ANATOMY LECTURE 30: The last four cranial nerves Effect of lesion In unilateral hypoglossal nerve damage at the level of brain stem, an attempt to protrude the tongue, it will deviate to the side of the lesion. If supranuclear lesion tongue deviates to opposite site of the lesion - cortex, at central cerebral right lesion deviate to left torgue if right one has lesion automatic , more to the left THANK YOU