Cranial Nerves Flashcards
Describe the function of CNI. How does it reach the brain?
Supplies sense of smell.
Passes upwards through the cribriform plate to the olfactory bulbs.
Describe the function of CNII. How does it enter the skull?
Supplies sense of vision.
Two nerves join at the optic chiasma.
Enters skull via optic canal.
What is the order of the cranial nerves?
CNI - olfactory nerve CNII - optic nerve CNIII - oculomotor nerve CNIV - trochlear nerve CNV - trigeminal nerve CNVI - abducens nerve CNVII - facial nerve CNVIII - vestibulocochlear nerve CNIX - glossopharyngeal nerve CNX - vagus nerve CNXI - accessory nerve CNXII - hypoglossal nerve
Describe the function/location of CNIII, IV, VI.
CNIII - arises from midbrain
CNIV - winds round from the back of the midbrain
CNVI - arises from the junction of the medulla and pons
Function - controls the movements of the eye and are involved in squints
Describe the function/location of CNV.
Largest of cranial nerves.
Attached to pons.
Main sensory nerve of face and mouth, supplies muscles of mastication.
Describe the function/location of CNVII,VIII.
Associated with the petrous temporal bone.
Arise together at the cerebello-pontine angle.
CNVII supplies salivary glands and muscles of face.
CNVIII supplies internal ear (supplies sensation of hearing)
Describe the function/location of CNIX, X, XI, XII.
Attached to medulla.
CNIX - supplies oropharynx
CNX - controls pharynx and larynx, branches also go to heart, stomach and intestines
CNXI - controls the pharynx and large muscle of neck (sternocleidomastoid and trapezius)
CNXII - arises from front of medulla, comes off in rootlets; controls tongue movements
ALL THESE NERVES ARE INVOLVED IN SWALLOWING AND SPEECH
What cranial nerves exit the skull via the superior orbital fissure of the sphenoid bone?
CNIII, IV, VI CNV1(ophthalmic division)
What are the five groups of branches of the facial nerve?
Temporal Zygomatic Buccal Marginal mandibular Cervical
How does the facial nerve exit the skull?
It is transmitted through the internal acoustic meatus and then travels through the facial canal, eventually exiting at the stylomastoid foramen.
What is the functional component of CNI?
Special visceral afferent - olfactory epithelium
What is the functional component of CNII?
Special somatic afferent - retina
What is the functional component of CNIII?
General somatic efferent - superior, medial and inferior rectus; inferior oblique and levator palpebral
What is the functional component of CNIV?
General somatic efferent - superior oblique muscle
What is the functional component of CNV?
General somatic afferent - skin of face and scalp, mucosa of oral cavity
Special visceral efferent - muscles of mastication and others (mylohyoid, digastric etc)
