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.