Cranial Nerves Flashcards
What modality is CNI
Special sensory- smell
What is the first cranial nerve
Olfactory nerve
Describe path of CNI
Olfactory receptors- cribriform plate- olfactory bulb- olfactory tract- lateral olfactory stria- primary olfactory cortex of uncus
Where is the primary olfactory cortex?
Uncus of temporal lobe
What is cranial nerve II
Optic nerve
What is the modality of cranial nerve II?
Special sensory- sight
Describe the path of the optic nerve
Optic disc- optic nerve- optic chiasm- nasal axons decussate and pass into contralateral optic tract- lateral geniculate nucleus of thalamus- visual cortex
Where is the visual cortex?
Above and below the calcarine sulcus of the occipital lobe
What surrounds the visual cortex?
The visual association area
What is the third cranial nerve?
Oculomotor nerve
What modality is the third cranial nerve?
Somatic motor to extra ocular muscles and parasympathetic to smooth muscle of eye via ciliary nucleus
Which cranial nerve nuclei are involved with cranial nerve III?
Oculomotor nucleus- somatic motor
Edinger-Westphal nucleus- parasympathetic
Describe the path of the somatic motor part of the oculomotor nerve
Oculomotor nucleus- ventrally through the midbrain tegmentum- many traverse the red nucleus- exit on medial aspect of crux cerebri- between posterior cerebral and superior cerebellar arteries in the wall of the cavernous sinus- superior orbital fissure- extra ocular muscles
Where do preganglionic parasympathetic neurones of CNIII terminate and what is there postganglionic course?
In the ciliary ganglion
In short ciliary nerve to innervate the sphincter pupillae and ciliary muscle in ciliary body.
What is the afferent limb of the pupillary light reflex?
Optic tract
What is the efferent limb of pupillary light reflex?
Oculomotor nerve
What is CNIV?
Trochlear nerve
What modality is CNIV
Somatic motor to superior oblique
Describe the path of CNVI
Trochlear nucleus in midbrain periaqueductal grey- pass dorsally and cross at the midline, leave the dorsal aspect of the brainstem at the level of the inferior colliculus-runs anteriorly in the lateral wall of the cavernous sinus through the superior orbital fissure- superior oblique
What is the sixth cranial nerve?
Abducent nerve
What is the modality of CNVI?
Somatic motor to lateral rectus?
Describe the path of the abducent nerve?
Abducent nucleus on the floor of the 4th ventricle- pass ventrally and emerge at the junction between the pons and the pyramid- pass anterior lay through cavernous sinus- superior orbital fissure- lateral rectus
What is the fifth cranial nerve and its constituent parts?
Trigeminal nerve
Ophthalmic, maxillary and mandibular nerve
What are the modalities of the constituents of the fifth cranial nerve?
Opthalmic nerve- somatic sensory to the skin of the forehead, eyelid, centre of nose
Maxillary nerve- somatic sensory to cheek, alla of nose, upper lid
Mandibular nerve- somatic sensory to lower lip,chin and side of face
Somatic Motor to muscles of mastication
What nuclei are involved with the trigeminal sensory pathway
Trigeminal sensory nucleus made up of
Chief sensory nucleus
Mesencephalic nucleus
Spinal nucleus
What sensory modality does the mesencephalic nucleus have.
Proprioception
What sensory modality does the chief sensory nucleus have?
Touch/ vibration
What sensory modality does the spinal nucleus of CNV have?
Pain/temperature
Which nucleus do the motor axons of CNV come from?
Trigeminal motor nucleus
What foramen does CNVi pass through
Superior orbital fissure
What foramen does CNVii pass through?
Foramen rotundum
What foramen does CNViii pass through?
Foramen ovale
What is the seventh cranial nerve?
Facial nerve
What modality is CNVII?
Sensory: anterior 2/3 of tongue, palate via geniculate nucleus
Motor: muscles of facial expression and stapedius
Parasympathetic: sublingual and submandibular glands via the submandibular ganglion and the lacrimal gland and nasal and oral mucus membranes via the pterygopalatine ganglion
Describe the path of the motor fibres of the seventh cranial nerve.
Originate in the facial motor nucleus of the caudal pontine tegmentum.
Pass dorsally and loop around the abducent nucleus beneath the flor of the forth ventricle.
Leave brainstem in the motor root of the facial nerve to travel to muscles.
