cranial nerves Flashcards
What are Cranial Nerves?
Bundles of sensory and/or motor fibers
Innervate muscles and glands and/or carry sensory input
where do cranial nerves come out
Emerge from the cranial cavity via foramina in the cranium
how many CN are there
12 cranial nerves
how are the CN numbered
numbered from rostral(closer to the nose) (CN I) to caudal (CN XII) (closer to the tail
VB- clockwise
Functions of Cranial Nerves
Motor fibers - voluntary muscle
Motor fibers - involuntary muscle, glands
Sensory fibers - general sensation from skin & mucous membranes
Sensory fibers - sensation from the viscera
Sensory fibers - unique sensations
Olfactory Nerve number
1
Olfactory Nerve - sensory both or motor
sensory
Olfactory Nerve - sense for what
Sensory for smell
olfactory nerve cell bodies located where
Cell bodies are in the olfactory organ (in the roof of the nasal cavity) and along the nasal septum
olfactory nerve exit where
Exits cranium via the cribriform plate of ethmoid bone
Optic Nerve what number
2
optic nerve sensory both or motor
sensory
optic nerve sense what
Sensory for vision
optic nerve path
The optic nerve begins in the retina, then exits through the optic canal to enter the middle cranial fossa and forms the optic chiasm, where the fibers from each side partially cross
why is the optic chiasm important
Optic chiasm give us depth perception – without the world would look 2-d
Oculomotor Nerve nunmber
III - 3
Oculomotor nerve sensory motor or both
motor
Oculomotor Nerve two nucleus
Somatic nucleus
Visceral nucleus
Somatic nucleus- of the oculomotor nerve
Motor for 4 of the 6 extra-ocular muscles (all except superior oblique and lateral rectus)
Extra ocular – muscle that move the eye balls
Visceral nucleus - of the oculomotor nerve
Motor (parasympathetic) for ciliary body and constrictor pupillae
Oculomotor Nerve exit where
Travels through the superior orbital fissure
Trochlear Nerve - number
IV - 4
Trochlear motor sensory or both
motor
trochlear nerve motor supply to
Motor to superior oblique, an extraocular muscle
length of the trochlear nerve
Smallest cranial nerve, but has the longest intra-cranial course
Trochlear Nerve exit where
Traverses superior orbital fissure to gain entrance to orbit and innervates superior oblique
Trigeminal Nerve what number
V
Trigeminal Nerve motor sensory or both
both
Trigeminal Nerve nulceus
1 motor nucleus - to muscles of mastication
3 sensory nuclei - sensation to face
Trigeminal Nerve 3 divsions
Ophthalmic - V1
Maxillary - V2
Mandibular - V3
Ophthalmic Division - trigeminal
V1
Sensory to upper face (front of head & nose)
Traverses superior orbital fissure
Maxillary Division- trigeminal
V2
Sensory to upper lip, maxillary teeth, palate, mucosa of nose
Exits via foramen rotundum
Mandibular Division number - trigemenial
V3
part of the mandibular division - trigeminal
sensory and motor
sesnory divsion of the mandibular divsion
Sensory to teeth and gums of lower jaw, skin of temporal region, part of auricle, lower lip and lower face
mandibular divsion motor divsion
Motor to muscles of mastication
Mandibular Division - V3 exits where
Motor and sensory roots combine and traverse foramen ovale
Abducens Nerve what number
VI - 6
abducens nerve motor
Motor to lateral rectus (an extraocular muscle
Facial Nerve number
VII - 7
Facial Nerve motor sensory or both
both
Facial Nerve Motor to
muscles of facial expression
Facial Nerve for taste of
Taste to anterior tongue and palate
facial nerve parasympathetic
Parasympathetic for submandibular, sublingual and lacrimal glands
fascial nerve path
VII traverses internal acoustic meatus (with VIII) –>, into facial canal –> exits the cranium through the stylomastoid foramen –> Runs forward through parotid gland and divides into branches
Vestibulocochlear Nerve number
VIII
Vestibulocochlear Nerve sensory motor or both
sensory
Vestibulocochlear Nerve sensory to
Vestibular portion for balance
Cochlear portion for hearing
Vestibulocochlear Nerve pathway
Traverses internal acoustic meatus to reach inner ear
Glossopharyngeal Nerve number
IX
Glossopharyngeal Nerve sensory motor or both
both
Glossopharyngeal Nerve motor
stylopharyngeus muscle
Glossopharyngeal Nerve sensory
Sensory for touch to pharynx, tonsil and posterior 1/3 of tongue
Sensory for taste to posterior 1/3 of tongue
sensory endings to wall of carotid sinus and to carotid body
Glossopharyngeal Nerve parasympathetic
parotid gland
Glossopharyngeal Nerve exits where
jugular foramen anterior to X & XI
Glossopharyngeal Nerve travels between
Passes between internal jugular vein and internal carotid artery
Vagus Nerve number
X
Vagus Nerve sensory, motor or both
both
pathway of vagus nerve
Traverses jugular foramen (with IX and XI) –> descends within carotid sheath between internal jugular vein and internal carotid artery –> enters thorax
Vagus Nerve Parasympathetic
Parasympathetic preganglionic fibers to heart, lungs and digestive system to left colic flexure
Vagus Nerve Sensory branch
carotid body
larynx
Taste to epiglottis
to skin of auricle and dura in posterior cranial fossa
Vagus Nerve motor
Gag reflex motor
larynx
Spinal Accessory Nerve number
XI
Spinal Accessory Nerve sensory, motor, or both
motor
Spinal Accessory Nerve motor
SCM and trapezius mm
Spinal Accessory Nerve formed by what
Formed by union of cranial and spinal roots
Spinal Accessory Nerve crosses where
Traverses jugular foramen with IX and X
Hypoglossal Nerve number
XII
Hypoglossal Nerve motor sensory or both
motor
Hypoglossal Nerve motor
intrinsic and extrinsic muscles of tongue
Hypoglossal Nerve exits through
hypoglossal canal
Hypoglossal Nerve is joined by what
Joined by branch from VPR of C1
