2k. Cranial Nerves Flashcards
Cranial Nerve Names
I = olfactory II = optic III = oculomotor IV = trochear V = trigeminal VI = abducens VII - fascial VIII = vestibulocochlea IX = glossopharyngeal X = vagus XI = accessory XII = hypoglossal
Cranial Nerve I
- Skull Exit
Cribriform plate through the mesethmoid bone
Cranial Nerve II
- Skull Exit
Optic foramen
Cranial Nerve III
- Skull Exit
Orbital fissure
Cranial Nerve IV
- Skull Exit
Orbital fissure
Cranial Nerve V
- Skull Exit
V1 = orbital fissure and rostral alar foramen (round foramen)
V2 = rostral alar foramen (round foramen)
V3 = Oval foramen
Cranial Nerve VI
- Skull Exit
Orbital fissure
Cranial Nerve VII
- Skull Exit
Stylomastoid foramen
Cranial Nerve VIII
- Skull Exit
Internal auditory meatus
Cranial Nerve IX
- Skull Exit
Jugular foramen
Cranial Nerve X
- Skull Exit
Jugular foramen
Cranial Nerve XI
- Skull Exit
Jugular foramen
Cranial Nerve XII
- Skull Exit
Hypoglossal foramen
Brainstem Nuclei
- Motor and Sensory Positions
- Motor nuclei are medial
- Sensory nuclei are lateral
Brainstem Nuclei
- Sensory Nuclei Divisions
- Somatic sensory neurones are lateral
- Special sense sensory neurones are in the middle
- Visceral sensory neurones are medial
Brainstem Nuclei
- Motor Nuclei Divisions
- Autonomic/visceral motor neurones are lateral
- Pharyngeal arch motor neurones are in the middle
- Somatic motor neurones are medial
Brainstem Nuclei
- Trigeminal nucleus
Cranial nerves III, IV and VI have no ganglia despite containing sensory proprioceptive fibres bringing information about eye position back to the brain.
They have embedded in the trigeminal nucleus of the brainstem as the mesenchephalic nucleus.
Therefore these cells are neural crest derived, not neural ectoderm like the true brainstem
Horner’s Syndrome
- Cause
Loss of sympathetic innervation of the head, caused by damage at any point on the sympathetic pathway.
Often caused by middle ear infection damaging the sympathetic nerves running through it
Horner’s Syndrome
- 6 Clinical Signs
- Mitosis (pupil constriction)
- Loss of sympathetic innervation of the circumferential dilatory muscles in the iris - Ptosis (lowering of the upper eyelid)
- Loss of sympathetic innervation to the deep leaf of elevator palpebral superioris - Enophthalmia (eyeball sinking posteriorly)
- Loss of sympathetic innervation to the periorbital smooth muscle and fascia - Conjunctival vascular engorgement
- Loss of sympathetic vasoconstrictive innervation to the eye is lost - Reduced intraocular pressure
- Horses sweat ventral to the eye
Horner’s Syndrome
- Characteristics
Unilateral
Non-painful
Feline Dysautonomia Syndrome
- Cause
Loss of parasympathetic innervation to the head
Feline Dysautonomia Syndrome
- Clinical Sign
- Mydriasis (pupil dilation)
- Loss of parasympathetic innervation of the radial constrictory muscles in the iris
