Cranial Nerves Flashcards
What is cranial nerve 1?
Olfactory nerve which arises from the cerebrum.
What is the course of CN1?
Olfactory nerve arises from receptors in the superior nasal concha and the nasal septum. It travels through the cribiform foramen of the ethmoid bone to form a rounded mass called the olfactory bulb. and travels to the cerebrum.
What is Cranial nerve II?
Optic nerve which arises from the cerebrum.
What is the course of Cranial nerve II?
Arises from the retina and enters the brain via the optic canal. At the optic chiasm, some of the fibres decassate before ascending up the brain stem to the contra lateral visual cortex.
Where do Cranial nerve I and II arise?
Cerebrum.
What is Cranial Nerve III?
Oculomotor nerve which arises from the midbrain.
What is the course of Cranial Nerve III?
Arises from the midbrain. It travels through the cavernous sinus and enter the eye socket through the superior orbital fissure. It innervates the extraocular muscles, excluding the lateral rectus and superior oblique.
What is Cranial Nerve IV?
Trochlear nerve which arises from the midbrain.
What is the course for Cranial Nerve IV?
Arises from the midbrain and travels through the cavernous sinus and enters the eye socket via the superior orbital fissure to innervate the superior oblique extra-ocular muscle.
Where do Cranial Nerve III and IV arise from?
Midbrain.
What is Cranial Nerve V?
Trigeminal nerve which has 3 sensory branches: V1, V2 and V3. Trigeminal nerve arises from the pons to form the Trigeminal ganglion
What is the V1 branch of the trigeminal nerve?
Ophthalmic nerve which exits the cranium via the superior orbital fissure to innervate the skin of: -
>the forehead and scalp
->nose bridge, frontal and ethmoid sinus
->upper eyelid, cornea and lacrimal gland.
What is the V2 branch of the trigeminal nerve?
Maxillary nerve which exits the cranium via the inferior orbital foramen. It innervates the;
Lower eyelid
Cheeks
Maxilla, maxillary sinus and its teeth, gums and superior palate
Upper lip
It provides parasympathetic supply to the lacrimal glands and nasal glands.
What is the V3 branch of the trigeminal nerve?
Mandibular nerve which exits the cranium via the mental form and to provide sensory innervation to the:
Lower lip
Mandible
Anterior 2/3 of the tongue
Sides of the face
Chin
What is the motor function of the mandibular nerve?
It innervates the:
Tensor villi palatini
Muscles of mastication
Tensor tympani
What is Cranial Nerve VI?
Abducens nerve which arises from the pons.
What is the course for Cranial nerve VI?
Arises from the pons and travels through the cavernous sinus to the superior orbital fissure to enter eye socket. It innervates the lateral rectus extra-ocular muscle for eye abduction.
What are the muscles of mastication?
Temporalis , lateral pterygoid, medial pterygoid and masseter muscle.
What is cranial nerve VII?
Facial nerve which arises from the pons and travels through the internal acoustic meatus to give off 3 branches:
-> Facial nerve proper
-> Chorda tympani
-> Greater petrosal nerve
It also gives off a nerve to the stapedius muscle.
Facial nerve innervates all the glands in the head, excluding the parotid gland, which is innervated by the mandibular branch of the trigeminal.
Where does the facial nerve travel?
Internal acoustic meatus
OR
Stylomastoid foramen
What is the facial nerve proper?
Facial nerve proper is the motor branch of the facial nerve which travels through the internal acoustic meats and exits the cranium via the stylomastoid foramen. It passes through the parotid gland and gives rise to branches for innervation of the muscles of facial expression.
Innnervates all the glands in the head excluding parotid.
What are the muscles of facial expression?
Orbicularis oris
Frontalis
Zygomaticus
Orbicularis oculi
Nasalis
What is the chorda tympani?
Branch of the facial nerve which travels through the tympanic membrane and courses alongside the lingual nerve (V3), providing taste sensation to the anterior 2/3 of the tongue.
Chorda tympani provides innervation to the sublingual and submandibular glands for salivation.
What is the innervation to the parotid gland?
Glossopharyngeal nerve.
What is the greater petrosal nerve?
Facial nerve branch from the pons to innervate the lacrimal gland and mucous glands of the pharynx, oral cavity and nose.
Damage leads to loss of lacrimation.
What is the posterior auricular nerve?
Facial nerve branch which innervates the intrinsic and extrinsic muscles of the ear.
Which suprahyoid muscles are innnervated by the branches of facial nerve?
Posterior belly of digastric
Stylohyoid muscle.
What is Cranial Nerve VIII?
Vestibulocochlear nerve, formed of the vestibular nerve and cochlear nerve which is important for hearing and balance, exiting the cranium via the internal acoustic meatus.
Where is the vestibular nuclei located?
Arises from the vestibular nuclei in the pons and medulla to exit the skull via the internal acoustic meatus to the vestibular system of the ear for balance.
Where is the cochlear nuclei located?
Arises from the cochlear nuclei in the medulla to exit the cranium via the internal acoustic meatus and provide fibres to the cochlea for hearing.
What is Cranial Nerve IX?
Glossopharhygneal nerve which arises from the medulla.
What is the innnervation by Cranial Nerve IX?
Glossopharyngeal nerve innervates:
Taste and sensation to posterior 1/3 of tongue
Middle ear and Eustachian tube
Parotid gland
Oropharynx for afferent gag reflex
Carotid sinus and carotid body for baroreceptors
What is the significance of the carotid sinus and carotid body?
Peripheral baroreceptors wrovides information about blood pressure and oxygen saturation.
What is Cranial Nerve X?
Cranial Nerve 10 which arises from the medulla to innervate the pharynx for swallowing, larynx for speech and abdominal and thoracic viscera. It is important for the efferent gag reflex.
What is Cranial nerve XI?
Spinal accessory nerve which arises from the medulla. It innervates the sternocleodomastoid and trapezius and can be tested by asking patient to look over their shoulder.
What is Cranial Nerve XII?
Vagus nerve which arises from the medulla and innervates the muscles of the tongue. Can be tested by asking patient to stick out tongue.
Where does the lingual nerve arise?
Branch of the V3 trigeminal nerve (mandibular nerve) for sensation to the anterior 2/3 of tongue.
Where does the inferior alveolar nerve arise?
Branch of V3 trigeminal nerve (mandibular) to innervate the lower jaw.
What is the innervation to the palatoglossus?
Vagus nerve
-> This is the only muscle of the tongue innervated by this.
What is the sensory function of the facial nerve?
Taste.
What is the motor function of the facial nerve?
Facial muscle expression.
Efferent part of the corneal reflex
What are the autonomic functions of the facial nerve?
Tear and salivary gland.
Innervation of carotid sinus
Glossopharyngeal nerve
Uvula deviated to the left
Vagus nerve
Longest cranial here
Vagus nerve
Smallest cranial nerve
Trochlear nerve
Longest intracranial cranial nerve
Trochlear
Which cranial nerves arise from the internal acoustic meatus?
Vestibulocochlear nerve
Facial nerve
Which nerves arise from the cribiform plate?
Olfactory nerve
Which nerve arises from the foramen ovale?
Mandibular nerve, V3 branch of trigeminal.
Which nerve arises from the foramen rotundum ?
Maxillary nerve, V2 branch of trigeminal nerve.
Which nerve arises from optic canal?
Optic nerve
Which nerve arises from the foramen lacerum?
Greater petrosal nerve
Which nerve arises from the superior orbital fissure?
Oculomotor nerve
Trochlear
Ophthalmic branch of trigeminal
Abducens
What are the parasympathetic cranial nerves?
CN3: pupil constriction via ciliary ganglion
CN7: facial nerve lacrimation, salivation and nasal glands
CN9: parotid gland
CN10: abdominal viscera for digestion
What is the innervation to the parotid gland?
Auriculotemporal
Greater auricular nerve
Which nerves travel through the superior orbital fissure?
Oculomotor nerve (III)
Trochlear nerve (IV)
Opthalmic nerve of trigeminal (V)
Abducens nerve (VI)
Opthamic vein
Where does all sympathetic innervation run from?
Sympathetic chain is between T1 and L2.
What is the innervation for sweat?
Sympathetic innervation.
Which structures travel through the optic canal?
Optic nerve
Opthalmic artery
Which nerve runs alongside the lingual nerve?
Chorda tympani
