Cranial Fossa and Nerves Flashcards
What is the optic nerve (CN II) an extension of?
Diencephalon
What is the nerve being highlighted?
Abducent nerve - CNVI
What is the pathway of the spinal accessory nerve (CNXI)?
Originates in the spinal cord
Enters foramen magnum and joins cranial root before passing through the jugular foramen
What nerve supplies taste to the posterior 1/3 of the tongue?
Glossopharyngeal CN IX
What nerves pass though the internal acoustic meatus?
CNVII - Facial nerve
CNVIII - Vestibulocochlear nerve
What is the route taken by the hypoglossal nerve (CNXII)?
Originates in the medulla oblongata (anterior to the olive)
Passes through the hypoglossal canal
Enters the root of the tongue above the hyoid
What do the sensory fibres of the facial nerve (CNVII) supply?
Supplies fibres to the auricle
Special sense of taste to the anterior 2/3rds of the tongue
What is the olfactory nerve an outgrowth of?
Telencephalon
What structures pass through the jugular foramen?
Internal jugular vein
CNIX - Glossopharyngeal nerve
CNX - Vagus nerve
CNXI - Spinal accessory nerve
Describe the pathway of the facial (CN VII) nerve
Originates in the pons
Passes through the internal acoustic meatus and into the temporal bone
What is this and what structure attaches to it?
Crista Galli
Dura Mater attaches here
What nerve is being highlighted?
Trochlear nerve - CNIV
Describe the route of the olfactory nerve
Passes from the mucosa of the nose through to the cribiform plate to synapse in the olfactory bulb
Tracts back to the prepiriform area of the amygdala
What is being highlighted?
Jugular Foramen
What is being highlighted?
Hypoglossal Canal
Describe the pathway of the vestibulocochlear (CN VIII) nerve?
Vestibular apparatus and auditory apparatus
Through the internal auditory meatus
To the pons/medulla oblongata
What is the role of the olfactory nerve (CN I)?
Provides the sense of smell
Describe the route of the optic nerve (CN II)
Runs from the retina through the optic canal, then forms the optic chiasm and optic tracts
What is being highlighted?
Cribiform plate
In which part of the brain is the visual cortex?
Occipital lobe
What are the divisions of the trigeminal nerve?
CNV1 = Ophthalmic division CNV2 = Maxillary division CNV3 = Mandibular division
Describe the role of CNV3?
Supplies sensory to the ear canal, parotid gland, lower jaw and teeth
Motor to the muscles of mastication, anterior belly of digastric, mylohyoid, tensor tympani, veli tensor palatini
What is the role of the abducent nerve (CNVI)?
Motor innervation to the lateral rectus
What are the branches of the trigeminal nerve and through which foramen do they leave the skull?
CNV1 = Ophthalmic, Superior orbital fissure CNV2 = Maxillary, Foramen rotundum CNV3 = Mandibular, Foramen ovale
What are the actions of the occulomotor nerve?
Supplies somatic motor and parasympathetic innervation
Motor - inferior oblique, superior rectus, inferior rectus and medial rectus, levator palpabrae
Parasympathetic - sphincter pupillae and ciliary muscle
What passes through the hypoglossal canal?
CNXII - Hypoglossal nerve
What do the green and blue arrows indicate?
Blue = Foramen rotundum Green = Foramen ovale
What lobes of the brain lie in the middle cranial fossa?
Temporal lobes
What is highlighted?
Olfactory tract and bulb
What is this foramen?
Foramen Lacerum
What is being highlighted?
Foramen magnum
What is the pathway taken by the glossopharyngeal nerve (CN IX)?
Originates in the medulla oblongata
Passes through the jugular foramen
What fossa is this and what part of the brain lies here?
Posterior fossa
Cerebellum
What is being highlighted?
Internal acoustic meatus
What nerves arise from the midbrain?
Occulomotor CN VIII
Trochlear CN IV
What is the function of the hypoglossal nerve (CN XII)?
Motor to all the intrinsic muscles of the tongue
Motor to all extrinsic except palatoglossus
Through which foramen does the vagus nerve (CNX) leave the skull?
Via the jugular foramen
What passes through the foramen spinosum?
Middle meningeal artery
What are the branches of the facial nerve that supply the muscles of facial expression?
Temporal Zygomatic Buccal Mandibular Cervical Posterior Auricular
What nerve is highlighted?
Occulomotor - CNIII
What structures pass through the cavernous venous sinus?
CN III, IV and V pass in the lateral wall
CN VI runs through the middle with the internal carotid artery
What muscles does the spinal accessory (CN XI) supply motor innervation to?
Trapezius and SCM
Describe the role of CNV2?
Supplies general sensory innervation to skin of cheek, lower eyelid, upper jaw and teeth, side of the nose and the mucosa of the mouth
What is the only cranial nerve in which all fibres cross to the oposite side?
Trochlear CN IV
What enters the middle cranial fossa through the foramen lacerum?
Internal carotid artery
Describe the pathway of the occulomotor nerve?
Arises in the midbrain
Travels through the superior orbital fissure to the orbit
Runs in the lateral wall of the cavernous dural venous sinus and through the annular ring
What is highlighted?
The middle cranial fossa
Describe the role of CNV1?
Supplies general sensory to the eye, lacrimal gland, eyebrow, skin of the forehead, nose.
What is the role of the trochlear nerve (CN IV)?
Provides motor fibres to the superior oblique muscle of the eye
Through which foramen does the Abducent (CNVI) pass through?
Superior orbital fissure
What is the foramen highlighted?
Foramen spinosum
What cranial nerve passes through the foramen magnum?
The spinal part of the spinal accessory nerve CNXI
What fossa is shown and what part of the brain sits here?
Anterior fossa
Frontal lobes of the brain
What foramen does the trochlear nerve (CN IV) pass through?
Superior orbital fissure to reach the orbit
