Testing the Cranial Nerves Flashcards
State the 12 Cranial Nerves
I: Olfactory II: Optic III: Oculomotor IV: Trochlear V: Trigeminal VI: Abducens VII: Facial VIII: Vestibulocochlear IX: Glossopharyngeal X: Vagus XI: Accessory XII: Hypoglossal
Where is the Nuclei for each of the Cranial Nerves? (2, 2, 4, 4)
Cranial Nerves I-II: Cerebrum
Cranial Nerves III-IV: Midbrain
Cranial Nerves V-VIII: Pons
Cranial Nerves IX-XII: Medulla
What is the modality for the 12 Cranial Nerves?
I: Olfactory - Sensory II: Optic - Sensory III: Oculomotor - Motor IV: Trochlear - Motor V: Trigeminal - Both VI: Abducens - Motor VII: Facial - Both VIII: Vestibulocochlear - Sensory IX: Glossopharyngeal - Both X: Vagus - Both XI: Accessory - Motor XII: Hypoglossal - Motor
Where does Cranial Nerve I, the Olfactory Nerve exit?
Cribiform Plate
Describe the route of Cranial Nerve I, the Olfactory Nerve
Primary neurones pass through Cribiform plate -> Synapse with mitral cells -> Olfactory tract -> Olfactory stria -> Amygdala -> Hippocampus
Why is smell intimately connected with emotions, memory, motivation and behaviour?
Because impulses run to the Amygdala and Hippocampus which are components of the Limbic system
Describe the route of Cranial Nerve II, the Optic Nerve
Eye - > Optic Nerve -> Optic Chiasm -> Optic Tract -> Lateral geniculate nucleus -> Optic radiation -> Primary visual cortex
Where does decussation of the Optic Nerve occur?
Optic Chiasm
Where is the Lateral Geniculate Nucleus located?
Thalamus
What is Scotomata?
Blind spots in visual fields
What is Hemianopia?
Decreased vision in half of visual field
What is Quadrantanopia?
Decreased vision in quarter of visual field
What test is used to assess Colour Blindness?
Ishihara Test
What conditions might Visual Fields assess for?
Scotomata
Hemianopia
Quadrantanopia
Which extrinsic eye muscle runs through the Trochlea?
Superior Oblique
What is the main connection between the Oculomotor, Trochlear and Abducens nerve?
Medial Longitudinal Fissure
What is the relevance of the Medial Longitudinal Fissure with respect to the Cranial nerves
Connection between the Oculomotor, Trochlear and Abducens nerve
What is the Direct and Consusual Response in the Pupillary light reflex?
Direct response = Constriction of pupil of same eye
Consensual response = Constriction of pupil of other eye
Ptosis is caused by a lesion in which Cranial Nerve?
Oculomotor Nerve (Cranial Nerve III)
What are the three branches of the Trigeminal Nerve?
Ophthalmic: V1
Maxillary: V2
Mandibular: V3
What is the modality of the Ophthalmic, Maxillary and Mandibular branches of the Trigeminal?
Ophthalmic: Sensory
Maxillary: Sensory
Mandibular: Both
Where does the Ophthalmic branch of the Trigeminal exit?
Superior Orbital Fissure
Where does the Maxillary branch of the Trigeminal exit?
Foramen Rotundum
Where does the Mandibular branch of the Trigeminal exit?
Foramen Ovale
What is the sensory / motor function of the Mandibular branch of the Trigeminal nerve?
Sensory: Sensation to anterior 2/3rds of tongue
Motor: Muscles of Mastication
What is the sensory / motor function of the Facial nerve?
Sensory: Taste to the anterior 2/3rds of tongue
Motor: Muscles of facial expression
What is the sensory function of the Glossopharyngeal nerve?
Sensory: Sensation and taste to the Posterior 1/3rds of the tongue
Where does the Vestibulocochlear nerve exit the skull?
Internal Acoustic Meatus
Where does Cranial nerves IX, X, XI exit the brain?
Jugular Foramen
Where does Cranial Nerve XII exit the brain?
Hypoglossal canal
Unilateral damage to nerves causes deviation of the uvula to which side?
Uvula will deviate towards UNAFFECTED side, or will deviate away from the affected side
What is the motor function of the Hypoglossal nerve?
Extrinsic / Intrinsic muscles of the tongue
Weakness / deviation of for example, the left hand side of the tongue suggests a nerve lesion of what side?
Left hand side (Ipsilateral)
