Cranial Nerves Flashcards
What type of neurone is CNI?
Special visceral afferent
What is the central connection of CNI?
Olfactory bulb
Where does CNI exit from the skull?
Olfactory foramina in cribriform plate
What is the function of CNI?
Sense of smell, from receptor cells in nasal mucosa
What is the functional test of CNI?
Pungent smell applied to each nostril
What is the neurone type of CNII?
Special somatic afferent
Where is the central connection of CNII?
Thalamus
Where does CNII exit the skull?
Optic canal
What is the function of CNII?
Vision, from the retina of the eye to the brain
What is the functional test of CNII?
Visual acuity test - Amsler grid to record visual defects/macular function
What are the neurone types of CNIII?
General somatic efferent
General visceral efferent - PS motor
Where is the central connection of CNIII?
Midbrain
Where does CNIII exit the skull?
Superior orbital fissure
What are the functions of CNIII?
Innervates levator palpebrae superioris, med/inf/sup rectus and inf oblique
Innervates sphincter pupillae and ciliary muscles for pupil constriction
What are the functional tests for CNIII?
Visual field test
Direct light, accommodation reflexes
What is the neurone type of CNIV?
General somatic efferent
What is the central connection of CNIV?
Midbrain
Where does CNIV exit the skull?
Superior orbital fissure
What is the function of CNIV?
Innervates superior oblique muscle
What is the functional test for CNIV?
Visual field test
What are the neurone types of CNV?
General somatic afferent - 1 and 2
Branchial motor - 3
What is the central connection of CNV?
Pons
Where does CNV exit the skull?
Superior orbital fissure - 1
Foramen rotundum - 2
Foramen ovale - 3
What are the functions of CNV?
Sensation in areas of the face - 1,2 and 3
Innervates muscles of mastication and tensor tympani - 3
What are the functional tests of CNV?
Reaction to touch with closed eyes in each region
Corneal reflex - 1
Jaw jerk reflex - 2
Open jaw against resistance - 3
What is the neurone type of CNVI?
General somatic efferent
What is the central connection of CNVI?
Pontomedullary junction
Where does CNVI exit the skull?
Superior orbital fissure
What is the function of CNVI?
Innervates lateral rectus which abducts the eye
What is the functional test of CNVI?
Visual field test
What are the neurone types of CNVII?
Special visceral afferent
General visceral efferent - PS motor
Special visceral efferent - branchial motor
Where it the central connection of CNVII?
Pontomedullary junction
Where does CNVII exit the skull?
Internal acoustic meatus - facial canal - stylomastoid foramen
What are the functions of CNVII?
Sensation from auricle and external acoustic meatus, taste from anterior 2/3 of tongue
Innervates submandibular, sublingual, lacrimal, glands, and nasal/oral cavity mucosal lining
Innervates muscles of facial expression, posterior belly of digastric, stylohyoid and stapedius
What are the functional tests of CNVII?
First is rarely tested
Assessment of dry mouth
Raise eyebrows, show teeth, blow out cheeks and close eyes against resistance
What is the neurone type of CNVIII?
Special somatic afferent
Where is the central connection of CNVIII?
Pontomedullary junction
Where does CNVIII exit the skull?
Internal acoustic meatus
What are the functions of CNVIII?
Vestibular branch - sensation of equilibrium and balance
Cochlear branch - sensation of hearing
What are the functional tests for CNVIII?
Vestibular branch - Dix-Hallpike positional test
Cochlear - whispered voice test
What are the neurone types of CNIX?
General somatic afferent
Special visceral afferent
General visceral afferent
General visceral efferent - PS motor
Special visceral efferent (branchial motor)
Where is the central connection of CNIX?
Medulla oblongata
Where does CNIX exit the skull?
Jugular foramen
What are the functions of CNIX?
Sensory input from posterior 1/3 of tongue, palatine tonsils, oropharynx, mucosa of middle ear, pharyngotympanic tube and mastoid air cells
Taste from posterior 1/3 of tongue
Sensory information from the carotid body
Secretomotor for parotid gland
Innervates stylopharyngeus, superior pharyngeal constrictor, assists in phonation and swallowing
What are the functional tests of CNIX and X?
Speech assessed for dysarthria pr dysphonia
Patient says ‘Ah’ to move palate and uvula
Patient puffs cheeks with lips closed (air will escape through nose with dysfunction)
Assess strength of cough
Swallow test
What are the neurone types of CNX?
General somatic afferent
Special visceral afferent
General visceral afferent
General visceral efferent - PS motor
Special visceral efferent - branchial motor
Where is the central connection of CNX?
Medulla oblongata
Where does CNX exit the skull?
Jugular foramen
What are the functions of CNX?
Sensory input from larynx, auricle, external acoustic meatus, dura mater of the posterior cranial fossa
Taste from palate and epiglottis
Information from aortic body, oesophagus, lungs, bronchi, heart, intestines
Innervates intrathoracic and intraabdominal viscera including all smooth muscle and glands
Innervates external laryngeal and pharyngeal muscles (except stylopharyngeus), permits phonation and swallowing, responsible for gag reflex
What is the neurone type of CNXI?
General somatic efferent
Where is the central connection of CNXI?
Medulla oblongata
Where does CNXI exit the skull?
Jugular foramen
What is the function of CNXI?
Innervates SCM, trapezius and the muscles of the soft palate
What is the functional test of CNXI?
Shrug shoulders, turn head against resistance on each side
What is the neurone type of CNXII?
General somatic efferent
Where is the central connection of CNXII?
Medulla oblongata
Where does CNXII exit the skull?
Hypoglossal canal
What is the function of CNXII?
Innervates all extrinsic and intrinsic muscles of tongue (except palatoglossal which is innervated by vagus)
What is the functional test of CNXII?
Assess tongue for wasting/deviation when pushed out, say yellow lorry to assess speech
What types of lesions and abnormal findings can be found in CNI?
Fracture of cribriform plate
Anosmia (loss of smell)
What types of lesions and abnormal findings can be found in CNII?
Direct trauma to orbit or eyeball
Pressure on optic pathway
Loss of pupillary constriction
Visual field defects
What types of lesions and abnormal findings can be found in CNIII?
Fracture involving cavernous sinus
Eye turns down and out
What types of lesions and abnormal findings can be found in CNIV?
Fracture of orbit
Inability to look down when eye is adducted
What types of lesions and abnormal findings can be found in CNV?
Injury to terminal branches - particularly V2
Loss of pain and touch sensations
What types of lesions and abnormal findings can be found in CNVI?
Fracture involving cavernous sinus or orbit
Eye fails to move laterally
What types of lesions and abnormal findings can be found in CNVII?
Laceration in parotid region
Intracranial hematoma (stroke)
Paralysis of facial muscles
Forehead wrinkles because of bilateral innervation of frontalis muscle
What types of lesions and abnormal findings can be found in CNVIII?
Tumour of nerve - acoustic neuroma
Progressive unilateral hearing loss
What types of lesions and abnormal findings can be found in CNIX?
Brainstem lesion or deep laceration of neck
Loss of taste on posterior third of tongue
What types of lesions and abnormal findings can be found in CNX?
Brainstem lesion or deep laceration of neck
Sagging of soft palate
What types of lesions and abnormal findings can be found in CNXI?
Laceration of neck
Paralysis of SCM and descending fibres of trapezius
What types of lesions and abnormal findings can be found in CNXII?
Neck laceration
Protruded tongue deviates toward affected side
