Cranial Nerves IX X XI XII_Dr Muntasir Hasnain_17_10_19 (1).pptx

Cranial Nerves IX X XI XII

1. Welcome Dr. Muntasir Hasnain Assistant Registrar Neurology Department NINSH

2. Topic IX, X, XI, XII cranial nerves & applied

3. IX Cranial Nerve The glossopharyngeal nerve

4. Leaves the anterolateral surface of the upper part of the medulla oblongata as a series of rootlets in a groove between the olive and the inferior cerebellar peduncle.

5. The nerve then descends through the upper part of the neck in company with the internal jugular vein and the internal carotid artery to reach the posterior border of the stylopharyngeus muscle, which it supplies.

6. Branches Tympanic Stylopharyngeal Tonsillar Nerve to carotid sinus P osterior third of tongue Lingual branches A communicating branch to the Vagus nerve

7. Clinical consideration A unilateral lesion to the glossopharyngeal nerve near its exit from the brainstem, will result in Damage to the SVA: ipsilateral loss of taste sensation from the posterior one-third of the tongue. Damage to the GVE (parasympathetic fibers ): reduction in salivary secretion of the parotid gland; Damage to the GVA : diminished visceral sensation from the pharyngeal mucous membrane, - loss of the gag reflex , - loss of the carotid sinus reflex . Damage to the SVE: paralysis of stylopharyngeus muscle leads to swallowing difficulty

8. Glossopharyngeal neuralgia I rritation of the ninth cranial nerve Causing extreme pain (electric shock-like) in the back of the throat, tongue and ear. Swallowing, chewing, talking, coughing, yawning or laughing can trigger an attack .

9. Most often a blood vessel compressing the nerve. Other causes include aging, multiple sclerosis, and nearby tumors.

10. Figure 2A (left). During MVD, a craniotomy is made in the skull. The glossopharyngeal nerve is often compressed by an artery near the brainstem . Lying close by is the vagus nerve. Figure 2B (right). A sponge is inserted between the nerve and the blood vessel to relieve the compression that causes the painful neuralgia attacks .

11. The Vagus Nerve (cranial nerve x) The term vagus is derived from the Latin word vagari meaning wandering . The vagus nerve (CN X) has the longest course and most extensive distribution . Sensory fibers outnumber parasympathetic fibers four to one.

12. In and below foramen are two sensory ganglia: superior ganglion -concerned with the general sensory component of the nerve. Inferior ganglion (nodose ganglion)- concerned with the visceral sensory components of the nerve. In the region of the superior ganglion are connections to CN IX and the superior cervical (sympathetic) ganglion.

13. In the neck, the vagus lies between the internal jugular vein and the internal carotid artery. It descends vertically within the carotid sheath, giving off branches to the pharynx, larynx, and constrictor muscles. The right recurrent laryngeal nerve curves below and behind the right subclavian artery to ascend at the side of the trachea behind the right common carotid artery.

14. The left recurrent laryngeal nerve curves below and behind the aortic arch to ascend at the left side of the trachea. From the root of the neck downward, the vagus nerve takes a different path on each side of the body to reach the cardiac, pulmonary, and esophageal plexuses

15. From the esophageal plexus, Enters abdomen through oesophageal hiatus in diaphragm as anterior and posterior trunks and contributes fibres to abdominal viscera and to coeliac, superior mesenteric and myenteric plexuses.

16. The Vagus nerve and the larynx The superior Laryngeal nerve- Sensory: Above the level of the vocal cord Motor: Cricothyroid muscle Bilateral paralysis :Horse, deep, high pitched voice The Recurrent Laryngeal Nerve- Sensory: Below the level of the vocal cord Motor: All the laryngeal muscles except the cricothyroid Paralysis of the vocal cord: Blurred and in effectual speech Bovine cough Bilateral paralysis: Stridor, respiratory obstruction

17. Clinical Testing ( IX and X CN are always tested jointly) POSITIVE FINDINGS-  Evaluate voice quality (hoarseness or dysarthria)  Ask patient to open mouth, say "ah", observe for elevation of soft palate, midline position of uvula.  Gag reflex, bilaterally  Swallowing  Taste (bitter) posterior one-third tongue

18. Clinical Testing ( IX and X CN are always tested jointly) Negative Findings Loss of voice quality (dysarthria or horseness ) Deviation of uvula towards non paralytic side Swallowing difficulty or nasal regurgitation Vagal irritation (bradycardia)

19. Disorders of vagus nerve cause Palatal weakness unilateral—minimal symptoms Bilateral-nasal regurgitation,nasal quality of speech, Pharyngeal weakness Unilateral pharyngeal wall drops on the affected side Bilateral—marked dysphagia Laryngeal weakness Unilateral damage—produce hoarseness with breathless speech and stridor Bilateral damage - produce stridor and breathless on exertion.

20. Clinical consideration of X CN Unilateral damage of the vagus nerve near its emergence: Damage to the SVE( branchiomotor fibers): will cause flaccid paralysis or weakness of muscles of pharynx and larynx Results in – -dysphagia -dysphonia -dyspnea -loss of the gag reflex (efferent limb).

21. Clinical Consideration of X CN Damage to the GVA: loss of general sensation from the soft palate, pharynx, larynx, esophagus, and trachea. Damage to the GVE: cardiac arrhythmias .

22. A bilateral lesion of the vagus nerve is incompatible with life, due to the interruption of parasympathetic innervation to the heart. Stimulation of the auricular nerve of cranial nerve X in the external auditory meatus cause reflex coughing, vomiting, Fainting through reflex activation of the dorsal vagal motor nucleus.

23. Where along the course of cranial nerve X can a lesion occur? An upper motor neuron lesion (UMNL): between the cortex and the nucleus ambiguus . Causes : ischemias , infarcts, or tumors. Bilateral UMNLs leads to pseudobulbar palsy.

24. A lesion at the level of the nucleus ambiguus and below is a lower motor neuron lesion (LMNL). A unilateral lesion of the lower motor neuron fibers results in a bulbar palsy .

25. Lower motor neuron lesions can occur from Mass lesions compressing the pons, Tumors of the jugular foramen, Aneurysm or intracranial dissection of vertebral artery Thrombosis of the sigmoid sinus or internal jugular vein Surgical mishaps -carotid end arterectomy or a thyroidectomy. Compression of the left recurrent laryngeal nerve by lung tumors or paratracheal lymph nodes compressing the nerve as it passes through the thorax.

26. ACCESSORY NERVE ( IXth Cranial Nerve)

27. A motor nerve Has two parts: Cranial Spinal Cranial Part: Emerges from the anterior surface of the medulla oblongata . Runs laterally in the posterior cranial fossa Joins the spinal root.

28. Spinal root : Formed by fibers of spinal nucleus situated in anterior grey column of spinal cord in upper five cervical segments.

29. Spinal Part: Arises from nerve cells in the ventral horn of the C1-C5 segments of the spinal cord Ascends alongside the spinal cord Enters the skull through the foramen magnum It then turns laterally & joins the cranial root. The two roots unite and leave the skull through the jugular foramen

30. Course of spinal root: Enters deep surface of sternocleidomastoid muscle which it supplies. Runs posteriorly & laterally crossing posteror triangle of neck. Passes beneath trapezius muscle which it supplies.

31. The supranuclear connections act on the ipsilateral sternocleidomastoid and on the contralateral trapezius.

32. Clinical Consideration: May be damaged by 1) Traumatic Injury 2) Tumours at the base of the skull 3) Fractures involving the Jugular foramen 4) Neck laceration

33. Asymmetric neckline due to diminished sternocleidomastoid muscle mass Ipsilateral weakness of sternocleidomastoid muscle causing weakness on turning the head against resistance away from the paralysed muscle. XI Nerve lesion

34. Damage to the accessory nerve (XI) may lead to contralateral weakness in the  trapezius causing….. Downward & outward rotation of the upper part of the scapula, sagging of the shoulder Weakness on attempting to shrug the shoulder. Dropping of the shoulder Difficulty in elevating the arm above the head XI Nerve lesion

35. Central irritation of accessory nerve produces clonic spasm of sternocleidomastoid & trapezius muscle leading to spasmodic torticollis. Spasmodic torticollis.

36. Lower Cranial Nerve Palsy Vernet syndrome  (  jugular foramen syndrome ): is a constellation of cranial nerve palsies due to a lesion at the jugular foramen such as a  glomus jugulare tumour  or  schwannoma . It consists of motor paralysis of: Glossopharyngeal nerve (CN IX) Vagus nerve (CN X) Accessory nerve (CN XI)

37. Glomus tumors ( paragangliomas ) are common causes of jugular foramen syndrome. Benign, slow-growing head and neck tumors Originates from the neural crest cells. Commonly arise in the jugular bulb ( glomus jugulare ), middle ear ( glomus tympanicum ), nodose ganglion of the vagus nerve ( glomus vagale )

38. Motor nerve

39. X cranial nerve Nucleus It is situated closed to midline immediately beneath the floor of lower part of fourth ventricle. It receives bilateral corticonuclear innervations except those nerve cell which supply genioglossus which only receives contralateral corticonuclear fibers

40. Course: It emerge from anterior surface of medulla oblongata between pyramid and olive. It crosses posterior cranial fossa and leaves the skull through hypoglossal canal.

41. Course of Hypoglossal Nerve It passes anteriorly & downward in neck. Supply muscle of tongue.

42. Segments of Hypoglossal nerve Intracranial: 1.Medullary 2.Cisternal 3.Canalicular Extracranial : 1.Oropharyngeal carotid space 2.Sublingual

43. Tongue muscles and their function The intrinsic muscles act to change the shape of the tongue. The extrinsic muscles act to protrude, elevate, and retract the tongue, as well as move it from side to side. The nerve is involved in controlling tongue movements required for speech, food manipulation (i.e. formation of bolus), and swallowing.

44. Function Of Hypoglossal Nerve CN XII supplies all the intrinsic & extrinsic muscles of the tongue except palatoglossus which is supplied by cranial nerve X.

45. The hypoglossal nerve (XII) is unique in that it is innervated bilaterally from both hemispheres motor cortex.

46. A lower motor neuron lesion will result in the tongue deviating to the ipsilateral side. The tongue deviates to the weak side because of the unopposed action of the intact contralateral genioglossus muscle. The result is the tip of the tongue deviates toward the paralyzed side. The paralyzed muscles show wasting, and the tongue becomes wrinkled on that side.

47. Common Pathologic condition affecting each segment of the XII nerve Medullary segment Cisternal segment Skull base segment Carotid space segment Sublingual segment Glioma Demylination Infarction Hemmorhage Aneurysm Basal Ectasia Meningioma Rheumatoid Arthritis Metastasis Nasopharyngeal Carcinoma Glomus Tumor Nerve sheath Tumor Nodal / Extranodal Carcinoma Metastasis Dissection Carcinoma Infection

48. Combined Lower Cranial Nerve Palsy

49. Pseudobulbar palsy: Lesion: Supranuclear lesion of the lower cranial nerves(IX,X,XI,XII) Lesion is bilateral and UMN type Patient present with– Indistinct , slurred and high pitched speech (Donald Duck or Hot Potato Dysarthria) Tongue-small, stiff or spastic What causes the lesions ? Bilateral repeated CVA Involving Internal capsule Demyelinating disease(MS) Motor Neuron Disease

50. Bulbar palsy: Site of lesion: Nucleus of the lower cranial nerves (IX,X,XI,XII) in medulla Lesion is bilateral and LMN type Patient present with Dysarthria, Dysphonia, Dysphagia nasal regurgitation tongue- wasted,fasciculation Causes: Motor Neuron Disease (MND) GBS Syringobulbia Brainstem Infarction Poliomyelitis Neurosyphilis Neurosarcoid

51. Collet- Sicard syndrome : Unilateral lesions of cranial nerves IX, X, XI, and XII. Tumours of the skull base, Coiling and dissections of the internal carotid artery, Multiple myeloma, Vasculitis , Carotid fibromuscular dysplasia, Shotgun injuries, Idiopathic cranial polyneuropathy, Atlas fractures, Occipital condyle fractures.

52. It passes laterally in the posterior cranial fossa and leaves the skull through the jugular foramen.

53. Villaret's syndrome:   ( retroparotid space syndrome, syndrome of retroparotid space) Combines  ipsilatral paralysis of the last four cranial nerves (IX, X, XI, XII) and Horner syndrome . Sometimes cranial nerve VII also involved. It may also involve the cervical ganglia of the sympathetic trunk. Paralysis is caused by a lesion in the  retroparotid space ,

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