Cranial nerves - TRIGEMINAL nerve FINALpptx

Cranial nerves presentation
Trigeminal nerve.

1. Group 4 trigeminal nerve

2. SNO NAME INDEX NUMBER S/NO NAME REG. NUMBER 1 OKORI DEBORAH U/240802071/BMI 2 OSIRE MOSES U/240801409/BMI 3 OCOL ANDREW U/240802221/BMI 4 EKWANG MICHAEL U/240801494/BMI 5 NALUYINDA STELLA U/240801300/BMI 6 NAMUKA JOY U/240802202/BMI 8 AUMA CAROLINE U/240800804/ BDU 9 KALUMA RACHEAL U/240802211/ BPT 10 MUGABI JOB U/240300078/BMI 11 OSAURO KENNETH PAUL U/2308147/BMI 12 GAMUKAMA MBABAZIZE U/240801642/BMI 13 FAIDA DAISY EUDINE U/240801559/BMI

3. OBJECTIVES General overview EMBRYOLOGY COURSE GANGLION and associated ganglion NUCLEI BRANCHES Clinical Correlates TEST

4. TRIGEMINAL NERVE( CNV ) The trigeminal nerve (CN V) is the largest cranial nerve. It’s a mixed nerve The principal general sensory nerve for the head (face, teeth, mouth, nasal cavity, and dura of the cranial cavity) and its motor to the muscles of mastication ( massete , mylohoid , tensor tympani, tensor veli palatini , anterior belly of digastric ). It emerges from the lateral aspect of the pons by a large sensory root and a small motor root The trigeminal nerve is a special Visceral efferent ( SVE ) i.e carry motor signals from the CNS smooth muscles and other body parts/ and General Somatic Afferent (GSA) nerve i.e. carry sensory information like pain and touch. It has three divisions namely Maxillary Ophthalmic Mandibular

5. 1. Special Visceral Efferent / Motor The SVE emerges separately but medial and close to its companion from the trigeminal motor nucleus found in the pontine tegmentum . Together they both pass through the tentorium cerebelli to the mouth of trigeminal cave ( Meckels cave)

6. Cont ….. SVE receieves corticonuclear fibers from both the cerebral hemispheres and also the reticular formation. The cells of the motor nucleus gives off axons the form the motor root supplying muscles of mastication which include Temporalis Masseter Lateral and medial pterygoid

7. 2. General Somatic Afferent / Sensory Component The GSA component provides sensory innervations from the face, mucous membranes, nasal and oral cavities, frontal sinuses and deep structures of the head. The fibers of the trigeminal nerve that reach the main sensory nuclei come from cell bodies in the trigeminal ganglion together with the direct fibers from the mesencephalic nucleus, they form a single, large, sensory root, attached to the central aspect of the pons .

8. Embryology of the trigeminal nerve The trigeminal ganglia is first visible in week 4 stage 10, initially developing from neural crest cells which separate from neural folds before neural fold fusion. After fusion receive contributions from the neural tube roof plate The trigeminal ganglia (CN V) is the first to become apparent and is the largest of the cranial nerve. Origin CN V arises from the basal plate of the embryonic pons Has both sensory and motor components, which develop from different embryological sources

9. SENSORY COMPONENT Originates from neural crest cells, ectodermal placode, particularly the trigeminal placode The trigeminal ganglion also called the gasserian or semilunar ganglion forms from The neural crest cells which contribute to the majority of neurons Ectodermal placode provides additional sensory neurons These give rise to the three division, ophthalmic nerve v1 (sensory), maxillary nerve v2 (sensory), mandibular nerve v3 (mixed) MOTOR COMPONENT The motor nucleus of the trigeminal nerve (CN V) develops from basal plate of the pons (ventral neural tube) Motor fibers innervate muscle derived from the first pharyngeal (branchial) arch. These include; Mucles of mastication (masseter, temporalis,Tensor tympani,Tensor veli palatini MYLOHYOID,Anterior belly of digastric

10. COURSE It originates from the 3 sensory nuclei and 1 motor nucleus. It extends from mid brain to the medulla OBLONGATA , At the level of the pons , the sensory nuclei emerge to form a sensory root . The motor nucleus continue to form a motor root. The sensory root expands in to the trigeminal ganglion located lateral to the cavernous sinus in the trigeminal cave in the temporal bone.

11. CONT….. The peripheral aspect of the trigeminal ganglion gives rise to 3 divisions; 1) ophthalmic nerve ( V1) 2) maxillary nerve ( V2) 3) mandibular ( V3 ) The motor nerve continues inferior to the sensory root along the flow of the trigeminal cave and its fibers only distributed to mandibular nerve .

12. Image showing the COURSE AND BRANCHES of nerve

13. TRIGEMINAL GANGLION Called also gasserion or semilunar ganglion which contains most of the CN V sensory axons cell bodies. This ganglion is situated within Meckel cave, a CSF filled space with dura mater lying over the temporal bone petrous portion. Meckel cave enclosed trigeminal ganglion and the 3 division roots. CN V neurons within ganglion are pseudo-unipolar neurons with 2 axonal branches, one extends proximally to the brainstem and the other distally towards one of the divisions hence these neurons can conduct action potential in 2 directions. Orthodromically with pain and temperature sensation directed towards brainstem. 2. Antidromically towards CN V branches.

14. ASSOCIATED GANGLION Otic Ganglion The otic ganglion is a parasympathetic ganglion that is located below the foramen ovale and medial to the mandibular nerve and it is adherent to the nerve to the medial pterygoid muscle. its functionally associated with glossopharyngeal nerve , and they reach the ganglion via the lesser petrosal nerve . The postganglionic secretomotor fibers reach the parotid salivary gland via the auriculotemporal nerve .

15. Submandibular Ganglion The submandibular ganglion is a parasympathetic ganglion that lies deep to the submandibular salivary gland and is attached to the lingual nerve. Preganglionic parasympathetic fibers reach the ganglion from the facial nerve via the chorda tympani and the lingual nerves . The trigeminal nerve is thus the main sensory nerve of the head and innervates the muscles of mastication. It also tenses the soft palate and the tympanic membrane.

16. Trigeminal nerve nuclei • The cranial nerve nuclei are a set of structures that process all sensory information from the face and control the muscles involved in chewing Although the cell bodies of sensory neurons are in the trigeminal ganglion, the central processes terminate in nuclei located in pons and medulla: 1. Principal sensory nucleus- in the pons (touch and pressure). 2. Spinal nucleus of trigeminal nerve- in the medulla (pain and temperature) 3. Mesencephalic nucleus- proprioception (not primarily for V2 , more for V3 ) • Ganglion: Meckel’s cave. .

17. TRIGEMINAL NERVE NUCLEI

18. 1. Central /principle pontine nucleus . Location ; Pons. Function; Picks sensations of discriminative touch, pressure and vibrations from the jaw.  2 TRIGEMINAL MOTOR NUCLEUS . Location ; Pons, medial to the principle pontine. Function  ;Motor innervation to the first pharyngial arch, muscles of mastication . 3 MESENCEPHALIC NUCLEUS Location; The midbrain Function; It receives unconscious feedback from the muscles of mastication, extraocular muscles and from the periodontal ligaments, This nucleus is responsible for jaw jerk flex .

19. 4.Spinal trigeminal nucleus . Location ; Medulla  oblongata.  Function ; It receives information from the peripheral processes and controls pain, temperature, proprioception and crude touch from the face.

20. TRIGEMINAL NERVE :BRANCHES (1) OPTHALMIC BRANCH V1

21. OPHTHALMIC BRANCH V1 It's A sensory nerve . Origin :trigeminal ganglion Course : lateral wall of cavernous sinus, and divides into into 3 branches which enter into the superior orbital fissure. Branches i )Lacrimal nerve it pierces through the lacrimal plate and lacrimal gland to innervate the skin of upper eyelid and conjunctiva ii)Frontal nerve goes beneath the roof of the orbit branching into supratrochlear and Supraorbital nerve supratrochlear nerve innervates the conjunctiva, skin of fore head and pulpabra . Supraorbital nerve innervate the eyelids and skin of fore head.

22. iii) Nasocilliary nerve; Its divided into 4 sub branches as, Sensory root which supplies the ciliary ganglion . Long and short cilliary nerve, innervate sympathetic fibers to dilator pupils Sensory to conea ,and iris. Posterior ethmoidal nerve, through the posterior ethmoid foramen and orbital ethmoid canal to innervate the sphenoid ethmoidal sinuses, ethmoid cells and dura. anterior ethmoidal nerve ,enter the anterior ethmoid sinus and foramen of the cribiform plate to innervate the roof of the nasal cavity . infra trochlear nerve . Which supplies to the skin of upper eye lid and cojunctiva

23. 2)MAXILLARY BRANCH V2 • V2 is purely sensory • Conveys sensation from midface, palate, nasal cavity, and upper teeth. • General somatic afferent (GSA) fibers – touch, pain, temperature

24. Course of the Maxillary Nerve Origin : Trigeminal ganglion in Meckel’s cave Exit : Leaves the middle cranial fossa through the f oramen rotundum Pathway : Enters pterygopalatine fossa and gives branches to pterygopalatine ganglion. passes laterally into the infraorbital fissure and becomes the infraorbital nerve. Exits via infraorbital foramen on the face. Terminal part : Divides into facial branches beneath the orbit.

25. Branches In Pterygopalatine Fossa: • Zygomatic nerve → zygomaticofacial & zygomaticotemporal • Pterygopalatine GAnglion → nasopalatine, posterior superior and inferior nasal nerve, palatine nerve & pharyngeal nerve posterior superior alveolar nerve In Infraorbital Canal: • infraorbital nerve- middle and anterior superior alveolar nerve on face: palpebral(lower eyelid), nasal(lateral nose), labial branches(upper lip).

26. Branches

27. Structures Innervated Skin: Lower eyelid, cheek, upper lip, side of nose , temporal region Mucosa: Nasal cavity, maxillary sinus, palate Teeth: Upper teeth and gingiva Dura mater: Middle cranial fossa ( via meningeal branch)

28. ILLUSTRATION SHOWING TYPE OF THE NERVE (3)MANDIBULAR BRANCH

29. Origin and course The mandibular nerve originates from the trigeminal ganglion of gasser and exits the skull through the foramen ovale. Ounce it reaches the viscerocranium, it divides into two divisions; Anterior and posterior divisions. Both divisions further divide into smaller branches that innervate the structures of the face. The sensory root of the mandibular nerve originates from the trigeminal ganglion.it has a short course across the middle cranial fossa, after which it exits the skull and enters the infratemporal The motor root originates from the motor nucleus of the trigeminal nerve. It passes below the trigeminal ganglion without synapsing with it then through the foramen ovale a, after traversing the foramen . It joins the sensory root of the nerve.

30. Cont ….. The mandibular division that passes between the medial pterygoid and tensor veli palatine muscles. here it gives off the meningeal branch and the nerve to the medial pterygoid muscle. It bifurcates into two divisions The anterior division ramifies and produces motor branch for the masticatory muscles as well as one sensory branch , the buccal nerve which innervates the cheeks The posterior division divides into three sensory branches ; the auriculotemporal , lingual and inferior alveolar nerves. The latter gives off off a motor branch which innervates the and the anterior belly of the digastic muscle and mylohyoid muscle.

31. BRANCHES Meningeal branch alias nervus spinosus ; it’s the earliest branch and it pasSes through the foramen spinosum and divides into branches that accompany the main branches of the middle meningeal artery, innervating the dura mater of the middle cranial fossa. Nerve to medial pterygoid ; its branches right after the meningeal branch prior to bifurcating into two divisions, its gives off twigs that innervate the medial pterygoid muscle then penetrates it and reaches the tensor typani and tensor veli palatini which it also innervates. Branches of the anterior division Buccal nerve ; it innervates the skin of the cheek and buccal mucosa with the anastomoses with the buccal branches of the facial nerve. The masseteric nerve ; it provides a branch that innervates the temporomandibular joint, and innervates the masseter muscle The deep temporal nerve ; it has two divisions the anterior and posterior branch and they both innervate the temporalis muscle The nerve to lateral pterygoid ; it enters the lateral pterygoid muscle to innervate it.

32. The posterior division is mostly sensory giving off three main branches The articulotemporal nerve. Lingual nerve. Inferior alveolar nerve

33. Summary

34. CLINICAL CORRELATES 1)TRIGEMINAL NEURALGIA A clinical condition that causeS neuropathic (burning-like) pain to the face within the sensory territory of the trigeminal nerve. caused by compression of the TRIGEMINAL Nerve by; AN Aneurysm, Tumor, Trauma, CLINICAL PRESENTATION Severe facial pain along V2 often triggered by light touch or wind FACIAL SENSORY LOSS FREQUENT BLINKING AND TEARING OF THE EYE triggered by chewing, speaking or brushing the teeth RELIEVED BY CARBAMEZAPINE

35. CONT…. 2.Inferior alveolar nerve block: procedure used to anesthetise the mandibular branch of TN. Commonly done in dental procedures to numb the mandible, including teeth and surrounding tissues 3.Corneal reflex (aka blink reflex)- natural involuntary response to stimulate the cornea causing both eyes to blink simultaneously. It protects the eye from foreign objects. 4. Cluster headache; Has a similar presentation with the trigeminal neuralgia, but this present severe headaches on the side of the head where the trigeminal nerve territory has been affected 5. Gasserian ganglion block medical procedure that involves injecting a local anaestheSIA or other medication into the gasserian ganglion. This procedure is normally used to treat pain due to trigeminal neuralgia. 6. Congenital defects involving facial sensation or chewing defects 7. treacher collins syndrome Disruption of the neural crest cell migration can lead to craniofacial syndromes; .

36. Test Assess facial sensation (light touch,pain,temperature ),OVER THE THREE DIVISIONS,V1,V2 AND V3 TEST JAW OPENNING AND CLOSING STRENGTH, CHECK CORNEAL REFLEX(AFFERENT) WEAKNESS OR SENSORY LOSS MAY INDICATE NERVE OR BRAIN STEM DAMAGE

37. References • Gray’s Anatomy, 42nd Ed. • Snell: Clinical Neuroanatomy • Blumenfeld: Neuroanatomy Through Clinical Cases, 3rd Ed .