Cranial nerves Dr. ayat eldomouky

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

Classification of cranial nerves Sensory cranial nerves: contain only afferent (sensory) fibers ⅠOlfactory nerve ⅡOptic nerve Ⅷ Vestibulocochlear nerve Motor cranial nerves: contain only efferent (motor) fibers Ⅲ Oculomotor nerve Ⅳ Trochlear nerve ⅥAbducent nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve Mixed nerves: contain both sensory and motor fibers--- ⅤTrigeminal nerve, Ⅶ Facial nerve, ⅨGlossopharyngeal nerve ⅩVagus nerve

Cranial Nerve I: Olfactory Arises from the olfactory epithelium in upper part of nasal cavity. Passes through the cribriform plate of the ethmoid bone Fibers run through the olfactory bulb and terminate in the primary olfactory cortex Functions solely by carrying afferent impulses for the sense of smell

Olfactory nerves

Olfactory nerve

Olfactory tracts Olfactory bulb Olfactory nerves

Cranial Nerve II: Optic Arises from the retina of the eye Optic nerves pass through the optic canals and converge at the optic chiasma Functions solely by carrying afferent impulses for vision

Cranial Nerve II: Optic Figure II Table 13.2

Optic nerve

The optic canal

Optic chiasmsa

Cranial Nerve V: Trigeminal nerve: roots (large sensory and small motor)

Trigeminal ganglion

Trigeminal divisions

Branches Ophthalmic nerve (Ⅴ1, purly sensory) leave the skull through the superior orbital fissure, to enter orbital cavity Frontal nerve Supratrochlear nerve Supraorbital nerve Lacrimal nerve Nasociliary nerve Anterior ethmoidal Internal and external nasal Infratrochlear Posterior ethmoidal ciliary

Maxillary nerve (Ⅴ2, sensory) Leave skull through foramen rotundum Branches Infraorbital nerve Zygomatic nerve 3 Superior alveolar nerve Ganglionic Pterygopalatine nerves

Mandibular nerve (Ⅴ3, mixed) Leave the skull through the foramen ovale to enter the infratemporal fossa Branches Post. Division: Auriculotemporal nerve Lingual nerve Inferior alveolar nerve ant. Division: Nerve of masticatory muscles Buccal nerve

Mandibular nerve

Otic ganglion

Auriculotemporal nerve

Lingual nerve

Submandibular ganglion

Inferior alveolar nerve Nerve to mylohyoid muscle

Facial nerve Roots: motor root Sensory root (nervus intermedius) V111

internal acoustic meatus facial canal in inner ear stylomastoid foramen

Facial nerve in ear

Pterygopalatine ganglion

Roots : From the greater petrosal nerve ( from the facial nerve) From the maxillary nerve which arises from the trigeminal ganglion Sensory root From the greater petrosal nerve ( from the facial nerve) parasympathetic root From the deep petrosal nerve ( from the nerve plexus around the internal carotid artery ) Sympathetic root

Branches: 1. orbital branches 2. nasal branches 3. palatine branches 4 Branches: 1.orbital branches 2.nasal branches 3.palatine branches 4.pharyngeal branches

Facial nerve distribution Greater petrosal nerve Nerve to stapedius Posterior auricular nerve Chorda tympani Five terminal branches Nerve to posterior belly of digastric muscle

Chorda tympani nerve

Cranial Nerve VIII: Vestibulocochlear Fibers arise from the hearing and equilibrium apparatus of the inner ear, pass through the internal acoustic meatus, Two divisions – cochlear (hearing) and vestibular (balance (equilibrium))

Cranial Nerve VIII: Vestibulocochlear Figure VIII from Table 13.2

Cranial Nerve IX: Glossopharyngeal Fibers emerge from the medulla, leave the skull via the jugular foramen, and run to the throat Nerve IX is a mixed nerve with motor and sensory functions Motor – innervates part of the tongue and pharynx, and provides motor fibers to the parotid salivary gland Sensory – fibers conduct taste and general sensory impulses from the tongue and pharynx

Cranial Nerve IX: Glossopharyngeal Figure IX from Table 13.2

Cranial Nerve X: Vagus The only cranial nerve that extends beyond the head and neck Fibers emerge from the medulla via the jugular foramen The vagus is a mixed nerve Most motor fibers are parasympathetic fibers to the heart, lungs, and visceral organs Its sensory function is in taste Paralysis leads to hoarseness Total destruction incompatible with life

Cranial Nerve X: Vagus

Cranial Nerve XI: Accessory Formed from a cranial root emerging from the medulla and a spinal root arising from the superior region of the spinal cord The spinal root passes upward into the cranium via the foramen magnum The accessory nerve leaves the cranium via the jugular foramen Primarily a motor nerve Cranial root: Supplies fibers to the larynx, pharynx, and soft palate Spinal root: Innervates the trapezius and sternocleidomastoid, which move the head and neck

Cranial Nerve XI: Accessory Figure XI from Table 13.2

Cranial Nerve XII: Hypoglossal Fibers arise from the medulla and exit the skull via the hypoglossal canal Innervates both extrinsic and intrinsic muscles of the tongue except palatoglossus, which contribute to swallowing and speech If damaged, difficulties in speech and swallowing; inability to protrude tongue

Cranial Nerve XII: Hypoglossal Figure XII from Table 13.2

Work sheet: Cranial Nerves Special Sense Nerves I,II,VIII Motor Nerves Eye—III,IV,VI Tongue—XII Palate, pharynx,larynx---XI “Rest of body” nerves IX,X Face and jaws VII, V Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves 1

Sensory cranial nerves Cranial exit Main action I Olfactory cells Cribrifom foramina Smell II Optic nerve Optic canal Vision VIII Vestibular ganglion Internal acoustic meatus Equilibrium Cochlear ganglion Hearing

Motor cranial nerves N. Nerves Cranial exit Main action III Occulomotor nerve Superior orbital fissure Motot to most of extraoccular muscles Parasympathetic to ciliary ganglion IV trochlear nerve Motor to superior obliquus VI Abducent nerve Motor to lateral rectus XI Spinal accessory nerve Jugular foramen sternocleidomastoid and trapezius Cranial accessory nerve Muscles of palate, pharynx and larynx XII hypoglossal nerve Hypoglossal canal Motor to muscles of tongue

Mixed cranial nerves N. nerves Cranial exit V Trigeminal nerve, Ophthalmic nerve Superior orbital fissure Maxillary nerve Foramen rotundum Mandibular nerve Foramen ovale VI Facial nerve Internal acoustic meatus IX Glossopharyngeal nerve Jugular foramen X Vagus

Important nerves 1. ophthalmic nerve Begin: as one branch of trigeminal ganglion End: divided into 3 branches enter the orbit through superior orbital fissure Branches: lacrimal nerve Frontal nerve: end as supratrochleal and supra orbital nerves Nasociliary nerve, give the following nerves; anterior and posterior ethmoidal , external and internal nasal infratrochlear nerve

Important nerves 2. maxillary nerve Begin: as one branch of trigeminal ganglion End: pass through foramen rotundum then enter the orbit and end as infraorbital nerve Branches: zygomatic nerve ganglionic nerve Post. Superior alveolar nerves middle Superior alveolar nerves ant. Superior alveolar nerves Infraorbital nerve

Important nerves 3. mandibular nerve Begin: as one branch of trigeminal ganglion End: enter the infratemporal fossa through the foramen ovale then divided into ant. And post. Division Branches of trunk: nerve to medial pterygoid muscle Branches of ant. division: Masseteric nerve Deep temporal nerve Buccal nerve Nerve to lateral ptrygoid muscle Branches of post. division: Auriculotemporal nerve Lingual nerve Inferior alveolar nerve

Important nerves 4. lingual nerve Begin: as one branch of post. Division of mandibular nerve End: descend medial to ramus of the mandible then runs forward to the tongue Branches: Carries general sensation of ant. 2/3 of the tongue Joined with chorda tympani (branch of facial nerve) which carries taste sensation of ant 2/3 of tongue, also carries preganglionic parasympathetic fibers to sublingual and submandibular salivary glands

Important nerves 5. inferior alveolar nerve Begin: as one branch of post. Division of mandibular nerve End: enter the mandibular canal and emerge from mental foramen as mental nerve Branches: Sensory to the lower teeth Nerve to mylohyoid muscle Mental nerve

Important nerves 6. facial nerve Begin: the 7th crasnial nerve start as motor and sensory roots End: enter parotid gland then divided into 5 branches Branches: Grater petrosal nerve. Chorda tympanic nerve Nerve to stapedius Posterior auricular nerve 5 terminal: temporal, zygomatic, buccal, mandibular and cervical branches

Important nerves 6. hypoglossus nerve Begin: the last cranial nerve End: pass forward lateral to carotid sheath to reach the tongue Branches: Muscular branches to all muscles of the tongue except palatoglossus muscle

Parasympathetic ganglions 1. pterygopalatine ganglion Site: pterygopalatine fossa Parasympathetic root (preganglionic): greater petrosal nerve branch from facial nerve Branches (postganglionic): orbital branches nasal branches greater and lesser palatine branch pharyngeal branch

Parasympathetic ganglions 2. 0tic ganglion Site: infratemoral fossa Parasympathetic root (preganglionic): lesser petrosal nerve branch from glossopharyngeal nerve Branches (postganglionic): Reach the parotid gland through auriculotemporal nerve

Parasympathetic ganglions 3. submandibular ganglion Site: submandibular triangle Parasympathetic root (preganglionic): chorda tympanic nerve branch from facial nerve Branches (postganglionic): Reach the submandibular and sublingual glands

Important notes MCQ All muscles of mastication innervated by mandibular nerve All branches of anterior division of mandibular nerve are motor except buccal nerve All branches of posterior division of mandibular nerve are sensory except nerve to mylohyoid muscle

Ex. For important MCQ The glossopharyngeal nerve is------------- Purely sensory Purely motor Mixed nerve None of above The facial nerve is--------------------

The hypoglossal nerve is------------------ Purely sensory Purely motor Mixed nerve Which of the following nerve is the contiuation of the maxillary nerve ----------------- Lacrimal nerve Frontal nerve Nasociliary nerve Infraorbital nerve

The posterior division of mandibular nerve give rise to all of the following except lingual nerve inferior alveolar nerve superior alveolar nerve auriculotemporal nerve The posterior division of the mandibular nerve innervates which of the following muscles: medial pterygoid muscle stylohyoid muscle mylohyoid muscle omohyoid muscle

chorda tympani nerve contains preganglionic parasympathetic fibers that synapse in…….. Pterygopalatine ganglion Otic ganglion Ciliary ganglion Submandibular ganglion Greater petrosal nerve contains preganglionic parasympathetic fibers that synapse in……..

Lesser petrosal nerve contains preganglionic parasympathetic fibers that synapse in…….. Pterygopalatine ganglion Otic ganglion Ciliary ganglion Submandibular ganglion Oculomotor nerve contains preganglionic parasympathetic fibers that synapse in……..

The trochelar nerve leaves the skull through………… Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum   The accessory nerve leaves the skull through………… Hypoglossal canal Jugular foramen The mandibular nerve leaves the skull through…………

The vagus nerve leaves the skull through………… Superior orbital fissure Foramen rotundum Hypoglossal canal Jugular foramen   The spinal root of accessory nerve innervates---- ------- Sternomastoid muscle Trapezius muscle Both a,b Neither a or b

Which of the following nerves carry smell sensation from nasal mucosa Lateral nasal nerve nasoplatine nerve sphenopalatine nerve olfactory nerve Which of the following nerves carry visual sensation from the retina Optic nerve Occulomotor nerve Trochlear nerve Abducent nerve

Which of the following statement concerning the lingual nerve is correct? It contains parasympathetic postganglionic fibers. It contains special sensory (taste) fibers from pos1/3 of tongue. It joins the chorda tympani nerve in the infratemporal fossa. It is a branch of the facial nerve in the temporal bone. The following statements concerning the chorda tympani are correct except which? It contains special sensory (taste) fibers. It joins the lingual nerve in the infratemporal fossa.

The branches of the posterior division of the mandibular nerve are sensory except: Lingual nerve Inferior alveolar nerve Auriculotemporal nerve. Nerve to mylohyoid muscle.