1: Cranial Nerves And Cranial Autonomics Flashcards
CN exiting cribiform plate
CN I
CN exiting optic canal
CN II
CNs exiting superior orbital fissure
3, 4, V1, 6
CN exiting foramen rotundum
V2
CN exiting foramen ovale
V3
CNs exiting internal acoustic meatus
7, 8
CNs exiting jugular foramen
9, 10, 11
CN exiting hypoglossal canal
12
Other names for first and second pharyngeal arches
First: mandibular arch
Second: hyoid arch
CNs associated with pharyngeal arches 1-6
1: CN 5
2: CN 7
3: CN 9
4&6: CN 10
All sympathetic fibers in the head
Are post-ganglionic from the superior cervical ganglion (of the sympathetic trunk)
How do all sympathetic fibers travel in the head?
Travel on vessels to the structures they innervate
An important named sympathetic N
Deep petrosal N
Which four CNs carry parasympathetic fibers?
3, 7, 9, 10
Pre-ganglionic fibers of Parasymps in the head
Arise in nuclei of brain stem -> synapse in 4 ganglia in the head
Four ganglia for parasymp fibers to synapse in the head
- Ciliary ganglia
- Pterygopalatine ganglia
- Otic ganglia
- Submandibular ganglia
How do post-ganglionic fibers of Parasymps travel to their structures?
Piggy-back on a branch of the Trigeminal
Nerve damage of CN 1
Anosmia
Only type of nervous tissue that can regenerate
Olfactory N (CN 1)
CN 2 path
Optic foramen -> enters cranium -> L and R optic N’s unite at optic chiasm -> optic tracts travel to lateral geniculate nucleus of thalamus -> occipital lobe
Nerve damage to CN 2
Anopsia (visual defects)
Which nerve is technically a “brain tract” as its really an outgrowth of the brain
CN 2 (Optic N)
4/6 extrinsic eye muscle supplied by the oculomotor N
- Superior rectus
- Medial rectus
- Inferior rectus
- Inferior oblique
Function of GVE portion of CN III
Pupil constriction + lens becomes spherical for near vision
Where are the edinger westphal nucleus and the trochlear nucleus?
Mesencephalon
Path of parasymp fibers of CN III
Travel to ciliary ganglion -> post-ganglionics to iris and ciliary M
Nerve damage of CN 3
Ptosis, paralysis of eye muscles -> strabismus, diplopia, trouble focusing
Nerve damage to CN 4
Superior oblique paralysis -> strabismus, diplopia
How does trochlear N get its name?
Means pulley bc it innervates the 1 extrinsic eye muscle that loops through a pulley-shaped ligament
GSA portion of the trigeminal N supplies what?
Face and scalp, conjunctiva, bulb of eye, mucous membranes of paranasal sinuses, nasal and oral cavities, external TM, meninges of anterior and middle cranial fossae
Origin of CN 5
Pons
Nerve damage of CN 5
Trigeminal neuralgia / tic douloureux
Tic douloureux symptoms
Intense, pulsating pain lasting minutes to several hours
V1 sensory from?
Cornea, nose, forehead, anterior scalp
Path for the three divisions of CN 5
V1: superior orbital fissure -> trigeminal ganglion -> pons
V2: foramen rotundum -> trigeminal ganglion -> pons
V3 branchial motor branches: pons -> foramen ovale -> muscles
V3 sensory branches: foramen ovale -> trigeminal ganglion -> pons
V2 sensory impulses from where?
Nasal mucosa, palate, gums, cheek
V3 sensory impulses from where?
Anterior 2/3 of tongue, cheek sin, lower jaw, over teeth, 1/3 from sensory fibers of auricle of ear
Nerve damage to CN 6
Paralysis of lateral rectus -> limits lateral eye movement, diplopia
Five major branches of the Facial N
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
What does the SVE portion of CN 7 supply?
Stapedius, stylohyoid, posterior belly of digastric, muscles of fascial expression (buccinator, platysma, occipitalis)
Sensory fiber path of CN 7
Tongue via chorda tympani branch -> tiny foramen -> geniculate ganglion of facial N
Somatic motor fiber path of CN 7
Pons -> internal auditory canal -> temporal bone -> stylomastoid foramen
Parasymp motor fiber path of CN 7
Pons -> internal auditory canal -> leaves with great petrosal N or chorda tympani N -> autonomic ganglion -> respective glands
Nerve damage to CN 7
Decreased tears and salivation, loss of taste to anterior 2/3 of tongue, facial nerve palsy
Facial nerve palsy symptoms
Paralyzed facial muscles, eyelid droop, sagging at corner of mouth
Path of CN 8
Vestibular + cochlear branches merge -> enter cranial cavity via internal auditory canal -> pons + medulla junction
Lesions in vestibular branch of CN 8
Loss of balance, N/V, dizziness
Lesion in cochlear branch of CN 8
Deafness
Other name for CN 8 (formerly)
Auditory N, acoustic N
Sensory fiber origin for CN 9
Taste buds, mucosa of posterior 1/3 of tongue, carotid bodies
Motor fiber origin of CN 9
Nuclei of medulla oblongata
Sensory fiber pathway of CN 9
Posterior 1/3 of tongue and carotid bodies -> inferior or superior ganglion -> jugular foramen -> pons
Somatic motor fiber path of CN 9
Jugular foramen -> stylopharyngeus
Parasymp motor fibers of CN 9 path
Otic ganglion -> parotid gland
Nerve damage to CN 9
Reduced salivary secretion, loss of taste to posterior 1/3 of tongue
Origin of CN X
Motor nuclei in medulla oblongata
Path of CN 10
Jugular foramen -> branches extensively in neck, thorax and abdomen -> sensory neuron cell bodies in superior and inferior ganglia
Nerve damage to CN 10
Paralysis -> variety of larynx problems like hoarseness, monotone, complete loss of voice, difficulty swallowing, GI impaired mobility
Spinal and cranial roots of CN 11: path
Superior to enter skull through foramen magnum -> >merges with cranial root -> leaves skull via jugular foramen
- Cranial root: travels with CN 10
- Spinal root: travels to SCM and trapezius
Nerve damage to CN 11
Paralysis of traps and SCM -> difficulty elevating shoulder and turning head to opposite direction
CN 12 path
Hypoglossal canal -> inferior to mandible -> inferior surface of tongue
Nerve damage to CN 12
Swallowing and speech difficulties due to impaired tongue movement
What happens if a single hypoglossal N (L or R) is paralyzed?
Protruded tongue deviates to the side of nerve damage
CN 1
Olfactory N
CN 2
Optic N
CN 3
Oculomotor N
CN 4
Trochlear N
CN 5
Trigeminal N
CN 6
Abducens N
CN 7
Facial N
CN 8
Vestibulocochlear N
CN 9
Glossopharyngeal N
CN 10
Vagus N
CN 11
Accessory N
CN 12
Hypoglossal N
