Cranial nerve- summary Flashcards
CN I- Olfactory
Special Visceral Afferent fibres for sense of smell
Connects to BRAIN
Passes through CRIBRIFORM PLATE
CN II- Optic
Special Somatic Afferent fibres for vision
Afferent limb for pupillary light reflex
Connects to BRAIN
Passes through OPTIC CANAL
CN III- Oculomotor
General somatic efferent and General visceral efferent fibres to EXTRAOCULAR muscles and PUPILLARY CONSTRICTOR muscles respectively- efferent limb for pupillary light reflex (LPS, I.oblique, SR, MR, IR)
CN III palsy > eye ‘down and out’
Connects to MIDBRAIN- passes through SUPERIOR ORBITAL FISSURE
CN IV- Trochlear
General somatic efferent to extraocular SUPERIOR OBLIQUE muscle
DEPRESSING/ ABDUCTING eye
Connects to midbrain- only CN leaves pontomesenphalic junction posteriorly
Passes through SUPERIOR ORIBITAL FISSURE
CN V- Trigeminal
3 sensory nuclei
Mesencephalic- proprioception
Principal- light touch and discrimination
Spinal- pain, temperature, crude touch
AFFERENT LIMB OF CORNEAL REFLEX (CN VII bilateral efferent)
Comes from PONS, 3 divisions: opthalmic, maxillary, mandibular
CN V1 - Opthalmic
General somatic afferent modality
Sensation from above lower eyelid
SUPERIOR ORBITAL FISSURE
CN V2- Maxillary
General somatic afferent modality
Sensation from lower eyelid to upper lip
FORAMEN ROTUNDUM
CN V3- Mandibular
General somatic afferent and special visceral efferent
Sensation from below upper lip
Motor- MUSCLES OF MASTICATION (masseter, pterygoids, temporalis), mylohyoid and anterior belly of the digastric)
FORAMEN OVALE
CN VI- Abducens
General somatic efferent fibres for EYE ABDUCTION
Innervates LATERAL RECTUS
Origin- PONTOMEDULLARY JUNCTION
SUPERIOR ORBITAL FISSURE
CN VII- Facial
Origin- pontomedullary region: passes through INTERNAL auditory meatus, exits through STYLOMASTOID FORAMEN
Loops around abducens nucleus
LMN lesions > upper and lower facial paralyis
UMN lesions > lower facial paralysis only
GSA- skin behind ear
SVA- taste to anterior 2/3 tongue
GVE- parasympathetic to lacrimal, sublingual and submandibular glands
SVE- muscles of facial expression
CN VIII- Vestibulocochlear
Special somatic afferent fibres for hearing and balance- detects changes in head motion
Origin- pontomedullary region > passes through INTERNAL auditory meatus; DOES NOT LEAVE SKULL
Cochlea transmits sound waves to mechanical ossicle movements to electrochemical APs
Vestibular branch responsible for equilibrium
CN IX- Glossopharyngeal
Origin- Medulla Oblongata
Passes trhough JUGULAR FORAMEN
Draws fibres from solitary nucleus (taste), nucleus ambiguus (motor)- fibres from inferior salivatory nucleus (parotid) and dorsal motor nucleus (DMX-pharyngeal sensation)
GSA- sensation to posterior 1/3 tongue, pharynx
SVA- taste to posterior 1/3 tongue
GVE- parasympathetic to parotid glands
SVE- motor to stylopharyngeus
CN X- Vagus
Origin- Medulla Oblongata
Passes though JUGULAR FORAMEN (IX, XI)
Parasympathetic innervation of viscera
Recurrent laryngeal nerve loops under right subclav a. and left aortic arch
GSA- skin around ear
SVA- taste and sensation to epiglottis
GVA- sensory information to body viscera
GVE- parasympathetic to glands of GI tract
SVE- Motor innerv. to soft palate, pharynx and larynx
CN XI- Accessory
Origin- Medulla oblongata and superior cervical cord region
Exits spinal cord in neck, enters skull through FORAMEN MAGNUM
General somatic efferent fibres to trapezius and sternocleidomastoid
CN XI- Accessory
Origin- Medulla oblongata and superior cervical cord region
Exits spinal cord in neck, enters skull through FORAMEN MAGNUM
General somatic efferent fibres to trapezius and sternocleidomastoid
