Cranial Nerves Flashcards
CN I
Olfactory
Innervation: Sensory (smell) from olfactory epithelium
Passes through: Cribriform plate
Test: smell test
CN II
Optic
Innervation: Sensory (vision) from retina
Passes through: Optic canal
Test: Menace response, obstacle
course, pupillary light reflex, and tracking response
CN III
Oculomotor
Innervation: Motor to D, V, and M rectus mm., ventral
oblique and levator palpebrae superioris m.
Parasympathetic to iris
sphincter m.
Passes through: Orbital fissure
Test: Dorsal, ventral, or medial movement of the pupil
look for lateral strabismus in lesioned animal, droopy upper eyelid,
pupillary light reflex with indirect response in other eye
CN IV
Trochlear
Innervation: Motor to dorsal oblique m.
Passes through: Orbital fissure
Test: Oblique deviation of pupil in lesioned animal
CN V1
Opthalmic br. of Trigeminal
Innervation: Sensory from globe, periorbita, nasal
mucosa, medial aspect of palpebrae
Passes through: Orbital Fissure
Test: medial canthus palpebral reflex
CN V2
Maxillary br. of Trigeminal
Innervation: Sensory from upper lip, nasal mucosa,
lateral aspect of palpebrae
Passes through: Round foramen and rostral
alar foramen
Test: lateral canthus palpebral reflex, test sensation to upper lip or nasal mucosa
CN V3
Mandibular br. of Trigeminal
Innervation: Sensory from lower jaw, rostral tongue and auriculotemporal area and motor to muscles of mastication
Passes through: Oval foramen
Test: sensation to lower jaw/lip or auriculotemporal area, or look
for atrophy of muscles of mastication
CN VI
Abducens
Innervation: Motor to retractor bulbi m. and lateral rectus
m.
Passes through: Orbital fissure
Test: Lateral movement of the eye, look for medial strabismus in lesioned
CN VII
Facial
Innervation: Motor to muscles of facial expression and
Sensory (taste) from rostral tongue. Parasympathetic to salivary and lacrimal gl.
Passes through: Stylomastoid foramen (motor fibers) and internal acoustic meatus
Test: Effects seen on muscles of facial expression. Look for deviation of philtrum, droopy ear, test Palpebral reflex - failure to close the palpebral fissure in lesioned animal
CN VIII
Vestibulocochlear
Innervation: Sensory for hearing and balance
Passes through: Internal acoustic meatus
Test: hearing, look for vestibular signs
CN X
Vagus
Innervation: Some motor to larynx, pharynx and esophagus. Sensory to ear canal and epiglottis. Parasympathetic to heart, lungs and abdomen
Passes through: Jugular foramen and
tympanooccipital fissure
Test: Listen to heart (↑ with lesion), listen to gut sounds (↓ with lesion).
Also can test for a gag reflex.
CN XI
Spinal Accessory
Innervation: Motor to trapezius, omotransversarius,
sternocephalicus and cleidocephalicus. Also
motor to larynx via recurrent laryngeal n.
Passes through: Jugular foramen and
tympanooccipital fissure
Test: Neurogenic atrophy of muscles with a lesion
XII
Hypoglossal
Innervates: Motor to extrinsic and intrinsic mm. of the
tongue
Passes through: Hypoglossal canal
Test: Tongue tone, look for atrophy, pull on tongue or watch drink
