Neuroanatomy Flashcards
Which extraocular muscles does the oculomotor nerve (CN III) innervate? Describe the associated eye movements
A third cranial nerve palsy results in…
Innervation and function:
- Superior rectus (elevates eye)
- Inferior rectus (depresses eye)
- Medial rectus (adducts eye)
- Intrinsic eye muscles (pupillary constriction/accommodation)
- Levator palpebrae superioris (eyelid opening)
CN III palsy:
- Eye adopts ‘down and out’ position
- Fixed, dilated pupil
- Ptosis
Which extraocular muscles does the trochlear nerve (CN IV) innervate? Describe the associated eye movements
A fourth cranial nerve palsy results in…
Innervation and function:
- Superior oblique (DAB: Depresses and ABducts eye)
CN IV palsy:
- Defective downward gaze
- Vertical diplopia
Which extraocular muscles does the abducens nerve (CN VI) innervate? Describe the associated eye movements
A sixth cranial nerve palsy results in…
Innervation and function:
- Lateral rectus (abducts eye)
Sixth cranial nerve palsy:
- Defective abduction
- Horizontal diplopia
Which mnemonic can be used to remember which cranial nerves innervate which extraocular muscles?
LR6 SO4
- Lateral rectus = CN 6
- Superior oblique = CN 4
- All the rest = CN 3
Describe the functions of the trigeminal nerve
A lesion affecting this nerve may cause…
Functions:
- Facial sensation
- Muscles of mastication
- Corneal reflex
Lesion:
- Trigeminal neuralgia
- Loss of facial sensation
- Paralysis of muscles of mastication
- Absent corneal reflex
Describe the functions of the facial nerve
A lesion affecting this nerve may cause…
Functions:
- Facial movement
- Taste (anterior 2/3 of tongue)
Lesions:
- Paralysis of upper + lower face (Bell’s palsy)
- Loss of taste
Describe the functions of the vestibulocochlear nerve
A lesions affecting this nerve may cause…
Functions:
- Hearing
- Balance
Lesions:
- Hearing loss
- Vertigo
- Nystagmus
Describe the functions of the glossopharyngeal nerve
A lesion affecting this nerve may cause…
Functions:
- Taste (posterior 1/3 tongue)
- Swallowing
- Mediates input form carotid sinus
Lesions:
- Loss of taste
- Loss of gag reflex
- Carotid sinus hypersensitivity
Describe the functions of the vagus nerve
A lesion affecting this nerve may cause…
Functions:
- Phonation
- Swallowing
- Innervates viscera
Lesion:
- Loss of gag reflex
- Uvula deviates AWAY from site of lesion
Describe the functions of the accessory nerve
A lesion affecting this nerve may cause…
Functions:
- Head and shoulder movement
Lesion:
- Weakness turning head to contralateral side
Describe the functions of the hypoglossal nerve
A lesion affecting this nerve may cause…
Functions:
- Tongue movement
Lesion:
- Tongue deviates towards site of lesion
Biceps reflex - which nerve root does this correspond to?
C5-C6
Triceps reflex - which nerve root does this correspond to?
C7-C8
Knee jerk reflex - which nerve root does this correspond to?
L3-L4
L3 rhymes with knee
Ankle jerk reflex - which nerve root does this correspond to?
S1-S2
S2 rhymes with shoe
1) Describe the location of Broca’s area
2) Describe the arterial supply to Broca’s area
3) A lesion affecting Broca’s area results in…
1) Dominant hemisphere (usually left), frontal lobe (inferior frontal gyrus)
2) Middle Cerebral Artery (MCA)
3) Expressive aphasia
1) Describe the location of Wernicke’s area
2) Describe the arterial supply to Wernicke’s area
3) A lesion affecting Wernicke’s area results in…
1) Dominant hemisphere (usually left), temporal lobe (superior temporal gyrus)
2) Middle Cerebral Artery (MCA)
3) Receptive aphasia
Which motor functions of the hand is the median nerve responsible for?
LOAF
- Lateral 2 lumbricals
- Opponens pollicis
- Abductor pollicis brevis
- Flexor pollicis
Which motor function of the hand is the ulnar nerve responsible for?
- Interossei
- Hypothenar muscles (abductor digiti minimi and flexor digiti minimi)
- Adductor pollicis
- Medial 2 lumbricals
Which nerve roots does the ulnar nerve arise from?
C8-71
i) Which nerve is responsible for supination of the hand?
ii) Which nerve is responsible for pronation of the hand?
i) Radial nerve
ii) Median nerve
