CN Course and Distribution Flashcards
III
Oculomotor
- Anterior midbrain
- Middle cranial fossa
- Lateral wall of cavernous sinus
- Divides into superior (LPS and SR) and inferior (MR, IR, IO)
- Passes through superior orbital fissure
- Eye muscles
Which oculomotor branch has somatic motor and parasympathetic nerves passing through?
Inferior
Superior
- GSE - LPS and SR
Inferior
- GSE - MR, IR,IO
- GVE - ciliary and sphincter pupillae
How does parasympathetic innervation of III get to its destination?
Hitch hikes on short ciliary nerves (of V1)
Sympathetic innervation of intrinsic eye muscles
Pre-gang neurons to superior cerivical ganglia
Post-gang neurons to long and short ciliary nn.
- Wrap around IC artery
- IC plexus
Innervates
- Dilator pupillae
- Ciliary mm.
- Superior tarsal m.
- SM
- Attached to LPS and lid
- Opens lid up ALL THE WAY
CN III lesions
Diplopia
Lateral strabismus
Mydriasis
Dry eye
Ptosis
VII
- Two roots from pons near PMJ
- Laterally in posterior cranial fossa with vestibulocochlear n.
- Enter IAM
- Pass through facial canal, branch into GP and CT
- Remaining VII is facial n. proper and continues down through stylomastoid foramen
- Posterior auricular n., Posterior digastric n., Stylomastoid branch off
- Pass THROUGH parotid to form plexus
- TZBMC
CN IX lesions
Supranuclear (in brain) = contralateral paralysis
- Tongue goes to side opposite of injury
Peripheral (after leaving brainstem) = ipsilateral paralsys
- Tongue goes to same side of injury/lesion
- “Lick your wounds”
Parasympathetic innervation of lacrimal gland
Pre-gang
- Super sal nuc.
- GP of VII
- Joins with DP (symp) = vidian n.
Post-gang
- Pterygopalatine gang
- Hitch hikes on zygomatic n. of V1
- Hitch hikes on lacrimal gland of V2 to innervate lac gland (what actually stimulates tears) via lac n. of V1
Parasympathetic: chorda tympani
Joins V3 on the way to sublingual and submandibular glands
Goes through submandibular ganglion
Posterior auricular n. innervates what muscle?
Auricularis posterior and occipitalis
Temporal n. innverates what muscle?
Motor - auricularis anterior/superior, frontalis, orbicularis oculi, corrugator supercilii, procerus
Zygomatic (malar) n. innverates what muscle?
Motor - orbicularis oculi and zygomaticus
Buccal (infraorbital) n. innervatess what muscle?
Motor - buccinator, orbicularis oris
Mandibular (maginal) n. innervates what muscle?
Motor - depressor labii inferioris, depressor anguli oris, mentalis
Cervical n. innervates what muscle?
Motor - depressor anguli oris and platysma
CN VII lesions
Bell’s Palsy - unilateral face paralysis from damage to SVE of VII
Temporary from dental procedures
- Inferior alveolar nerve block into parotid bed
- Improves when anesthetic wears off
Affected at stylomastoid foramen
CN IX
- Anterior medulla
- Passes laterally in posterior cranial fossa
- Jugular foramen
- Descends through upper part of neck to back of tongue
Tympanic n.
Branch of IX
- Enters middle ear cavity
- Sensory and pre-gang para fibers
- Forms part of tympanic plexus
Tympanic plexus
IX br
Sensory and sympa to middle ear cavity, pharyngotympanic tube, mastoid air cells
Lesser petrosal
IX br
- Travels through foramen ovale
- Fibers synapse in otic gang
- Travel to parotid
- Hitch hiking on V3, auriculotemporal n.
Parasympathetic innervation of parotid
Pre-gang neuron
- Inferior sal. nuc
- IX exits jugular foramen
- Tympanic n. of IX joins tympanic plexus = lesser petrosal n.
- Lesser petrosal exits foramen ovale
Post-gang neuron
- Otic gang
- Hitch hikes on auriculotemporal n. of V3
X
- Anterior medulla
- Laterally pass through posterior cranial fossa
- Pass through jugular
- Descends through neck along carotid arteries and internal jugular vein in carotid sheath
- Through mediastinum
- Pierces diaphragm with esophagus
- Terminal br in abdomen
- Most extensive distribution
X br
Pharyngeal
Superior laryngeal
- Internal laryngeal
- External laryngeal
Recurrent laryngeal
Pharyngeal plexus components
IX - glossopharyngeal n.
X - vagus n.
XI - accessory n., cranial part