4.1 Course of the Cranial Nerves Flashcards
CNI
Consists of peripheral olfactory processes in the olfactory mucosa.
Central processes that return information to the brain.
Once the nerves penetrate through the BM of nasal mucosa, they enter the cranial cavity through the cribriform plate of ethmoid.
CNII
Convergence of retinal ganglion cell axons.
Leaves bony orbit through optic canal in sphenoid bone.
Runs along surface of middle cranial fossa to primary visual cortex.
CNIII
Occulomotor nucles/edinger-westphal nucleus
Pierces dura
Enters lateral aspect of cavernous sinus.
Receives beaches from internal carotid plexus (Fibres to not combine, only hitch hick in sheath)
Leaves cranial cavity via superior orbital fissure.
Divides into superior - SR, LPS
Inferior - IO, MR, IR
CNIV
Trochlear nucleus (posterior midbrain) Ant/Inf Pierce dura Through cavernous sinus lateral wall Superior orbital fissure SO4
Contents of Cavernous sinus? OTOMICAT
CNIII O CNIV T CNV1 O CNV2 M CNVI A Internal carotid A
CNV
At pons, mesencaphalic, principal sensory and spinal nuclei merge - sensory root.
In middle cranial fossa, sensory root expands –> trigeminal ganglion (in trigeminal cave, lateral to cavernous sinus)
Gives rise to: CNV1, CNV2, CNV3
Motor nucleus –> Motor root
Passes inferiorly to sensory root
Only to CNV3
CNV1
Trigeminal ganglion
Lateral wall of cavernous sinus
Through superior orbital fissure
Branches: frontal, lacrimal, nasociliary
CNV2
Trigeminal ganglion Lateral wall of cavernous sinus Inferior to V1 Foramen rotundum Pterygopalatine fossa 14 terminal branches innervating maxillary prominence 1st pharyngeal arch structures.
CNV3
Trigeminal ganglion Foramen ovale 4 terminal branches: Buccal Inferior alveolar Auriculotemporal Lingual Innervate mandibular prominence of 1st pharyngeal arch
CNVI
Abducens nucelus in pons Cavernous sinus SOF Orbit LR4
CNVII - Intracranial
Facial motor nucleus, nucleus solitarius, superior salivatory nucleus
Large motor root, small sensory root
IAM in petrous part of temporal
Facial canal - roots fuse to form facial nerve
Geniculate ganglion
Greater petrosal nerve (autonomic)
Nerve to stapedius
Chorda tympani
Exits cranium via stylomastoid foramen of temporal bone.
CNVII - Extracranial
Turns superiorly anterior to outer ear Posterior auricular nerve branch Through parotid gland Motor branches to posteiror belly of digastric and stylohyoid Parotid pleus: Temporal branch Zygomatic brach Buccal branch Marginal mandibular branch Cervical branch Muscles of facial expression
CNVIII
Components combine in ponsand emerge through IAM of temporal bone
Splits formin vestibular and cochlear nerves
Organ of corgi and vestibular system
CNIX
Medullar oblongata Jugular foramen Tympanic nerve aises --> otic galnglion via lesser petrosal nerve Outside JF - superior and inferior petrous ganglia Contain cell bodies of sensory CNIX Branches to parotid Desends down neck anterior to ICA At inferior margin of stylopharyngeus - motor branches Carotid sinus nerve - carotid sinus/body Terminates in pharynx: Lingual branch Tonsil branch Pharyngeal branch
CNX
JF (911)
Auricular branch in cranium - sensation of posterior part of EAM and external ear
Carotid sheath, inferiorly with CCA
RVN passes anterior to subclavian and posteiror to sternoclavicular joint enters thorax
LVN passes inferiorly between LCCA and LSubclavA, posterior to sternoclavivular joint, enters thorax.
Pharyngeal branches –> Muscles of pharynx and soft palate
SLN –> External LN - cricothyroid of larynx
SLN –> Internal LN - sensory to laryngopharynx and superior larynx
RLN (R) hooks beneath right subclavian A and ascends to larynx - muscles of inner larynx except cricothyroid
Right vagus –> Post vagal trunk
Left vagus –> Ant, vagal trunk
Branches from these innervate oesophagus, bowels
RLN (L) hooks under arhcof aorta and ascends to innervate intrinsic muscles of larynx
Cardiac branches to heart - heart rate and visceral sensation
