Cranial Nerves Flashcards
What property of cranial nerves makes them prone to compression?
They are soft and pass through bony foramina
Which type of nerve fibre has all of its cell bodies in the CNS chain?
somatic motor (efferent) fibres
What cranial nerves deal with only sensory fibres?
Olfactory (I)
Optic (II)
Vestibulocochlear (VIII)
Which cranial nerves deal with only motor functions?
Oculomotor (III) Trochlear (IV) Abducens (VI) Accessory (XI) Hypoglossal (XII)
Which cranial nerves contain both afferent and efferent fibres?
Trigeminal (V)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
Through which foramen do fibres of the olfactory nerve pass?
Foramen in the cribiform plate of the ethmoid bone
What are the functions of the olfactory nerve?
Smell
What clinical problems can affect the olfactory nerve?
Fracture of cribiform plate can tear fibres causing anosmia
What foramen does the optic nerve pass through?
The optic canal
What is the optic nerve responsible for?
vision
What foramen does the oculomotor nerve pass through ?
Superior orbital fissure, after emerging from the midbrain
What functions are carried out by the oculomotor nerve?
Eyelid and eyeball movement,
Pupil constriction
Ciliary muscle innervation (accommodation)
What is the path of the trochlear nerve?
Emerges from the midbrain and exits via the superior orbital fissure
Functions of trochlear nerve?
Extraocular muscle innervation, turns eye downwards
Path of the Abducens nerve?
Emerges between pons and medulla and exits via the superior orbital fissure
Function of abducens nerve?
Moves the eye
Pathway of the Trigeminal V1 nerve?
Pons - trigeminal ganglion - superior orbital fissure
Trigeminal V1 functions?
Sensory of cornea, forehead, scalp, eyelids, nose, and sinuses
Where does the V2 of trigeminal exit?
foramen rotundum
Where does V3 of Trigeminal exit?
Foramen Ovale
Functions of the Trigeminal V3?
Sensory of mandibular are and forward 2/3 of tongue.
Motor innervation of the muscles of mastication
Facial nerve pathway?
N.B 3 exit paths
between pons and medulla - internal acoustic meatus/facial canal/stylomastoid foramen.
Functions of Facial nerve?
Muscles of facial expression Middle ear function (stapes) Parasympathetic innervation of salivary/lacrimal/nasal glands. taste from front of tongue External acoustic meatus general sense.
Common condtion due to facial nerve injury?
Bell’s palsy - struggle frowning, eyelid movements, teeth baring etc
