Neurolocalisation/Examination Flashcards
What is the classical pyramidal posture?
In arm:
Flexor > extensors
In leg:
Extensor > Flexor
Thenar wasting is seen in _____________ palsies.
Median nerve
Hypothenar wasting is seen in _____________ palsies.
Ulnar nerve
Winging of the scapula is seen in _________________ lesion.
Long thoracic nerve
Fasciculations imply denervation and are commonly seen in (upper/lower) motor neuron lesions.
Lower
When is pes cavus seen?
px with longstanding muscle weakness eg. hereditary illnesses like Charcot Marie Tooth, Muscular Dystrophy
What is pronator drift a sign of?
Subtle upper motor neuron weakness
When would a px use a reacher?
Proximal weakness
When would a px use utensils with modified handles?
Distal weakness/clumsiness
What is rigidity a sign of?
UMN lesion
What does a positive supinator catch sign indicate?
Upper motor neuron lesion
What does a positive knee catch sign indicate?
Upper motor neuron lesion
What is a ankle jerk clonus indicative of?
Upper motor neuron lesion
What is the (i) root (ii) nerve (ii) and (iii) plexus involved in a biceps reflex?
i) C5/6
ii) Musculocutaneous
iii) Upper brachial (Lateral cord)
What is the (i) root (ii) nerve (ii) and (iii) plexus involved in a triceps reflex?
i) C7/8
ii) Radial
iii) Lower brachial (posterior cord)
What is the (i) root (ii) nerve (ii) and (iii) plexus involved in a brachioradialis (supinator) reflex?
i) C5/6
ii) Radial
iii) Upper brachial (posterior cord)
What is the (i) root (ii) nerve (ii) and (iii) plexus involved in a quadriceps (knee) reflex?
i) L2/3/4
ii) Femoral
iii) Lumbosacral
What is the (i) root (ii) nerve (ii) and (iii) plexus involved in a ankle reflex?
i) S1
ii) Sciatic and Tibial
iii) Lumbosacral
What is the optimal stretch of a muscle when assessing its stretch reflex.
Mid flexion
What can be done to reinforce a reflex when it cannot be initially elicited?
1) Clench teeth
2) Clasp hands together and pull (Jendrassik maneuver)
What are the (i) main muscle (ii) nerve and (iii) root assessed in shoulder abduction power?
i) Deltoid (middle)
ii) Axillary nerve
iii) C5
What are the (i) main muscle (ii) nerve and (iii) root assessed in elbow flexion power?
i) Biceps brachii
ii) Musculocutaneous
iii) C5/6
What are the (i) main muscle (ii) nerve and (iii) root assessed in elbow extension power?
i) Triceps
ii) Radial
iii) C7/8
What are the (i) main muscle (ii) nerve and (iii) root assessed in wrist extension power?
i) Extensor carpi radialis/ulnaris
ii) radial nerve
iii) C6
What are the (i) main muscle (ii) nerve and (iii) root assessed in finger extension power?
i) Extensor digitorum
ii) Radial
iii) C7
What are the (i) main muscle (ii) nerve and (iii) root assessed in finger abduction power?
i) Dorsal interossei
ii) Ulnar
iii) T1
What are the (i) main muscle (ii) nerve and (iii) root assessed in thumb abduction power?
i) Abductor pollicis brevis
ii) Median
iii) T1
What are the (i) main muscle (ii) nerve and (iii) root assessed in hip flexion power?
i) Iliopsoas
ii) lumbar, femoral
iii) L1/2
What are the (i) main muscle (ii) nerve and (iii) root assessed in hip extension power?
i) Gluteus
ii) Inferior gluteal
iii) S1
What are the (i) main muscle (ii) nerve and (iii) root assessed in knee flexion power?
i) Hamstrings
ii) Sciatic
iii) S1
What are the (i) main muscle (ii) nerve and (iii) root assessed in knee extension power?
i) Quadriceps
ii) Femoral nerve
iii) L3
What are the (i) main muscle (ii) nerve and (iii) root assessed in ankle dorsiflexion power?
i) Tibialis anterior
ii) Common peroneal
iii) L5
What are the (i) main muscle (ii) nerve and (iii) root assessed in ankle plantarflexion power?
i) Soleus, Gastrocnemius
ii) Tibial
iii) S1
What are the 2 sensory modalities that should be tested in a sensory examination?
1) Pin prick (Spinothalamic)
2) Proprioception (DCML)
What are saccadic eye movements?
The eyes “jump” from one target to the next with perfect accuracy
What is the term for impaired saccadic eye movements?
Ocular dysmetria/Dysmetric saccades
What is “broken pursuit”?
Saccadic intrusions into pursuit eye movement:
- eyes are unable to follow the target with accuracy, necessitating corrective adjustments to reacquire the target
What is nystagmus?
Slow and rapid, repetitive, uncontrolled movements of eye
What are 3 eye movement signs that are indicative of cerebellar dysfunction?
1) Dysmetric saccades
2) Broken pursuit
3) Nystagmus
What are 3 upper limb signs that are indicative of cerebellar dysfunction?
1) Rebound
2) Finger nose dysmetria
3) Dysdiadochokinesis
What are the corrective movements often seen in voluntary movement (eg. finger nose dysmetria test)?
Intention tremors
What test of the trunk can be used to assess the cerebellar function?
Get px to cross him arm and sit up
- if sways → truncal ataxia
What are 2 test of the lower limbs that can be used to assess cerebellar function?
1) Heel shin test
2) Gait (regular and tandem)
What is heel shin ataxia?
Struggle to place heel on knee and run it down shin in heel shin test
- indicative of cerebellar dysfunction
What is a cerebellar gait?
Broad-based gait
→ lose balance when asked to catwalk
How does one assess dysdiadochokinesis?
Ask to slap back of hand and flip between supination and pronation
Why is the jaw spared in cavernous sinus lesions?
CN3,4,5,6 all traverse through cavernous sinus
BUT V3 doesnt → supply mandible
How are gliomas defined in diagnosis?
Molecular/genetic profile
Which cranial nerve could be lesioned in a aortic dissection?
CNXII: Hypoglossal nerve
What are 4 common causes of olfactory sense disruption?
1) Cribiform plate injury (Frontal head injury)
2) Rhinitis
3) Kallman Syndrome
4) Parkinson disease
What are the testable attributes of vision?
1) Acuity
2) Visual field
3) Colour
How do the etiology of acuity and visual field defects differ?
Acuity
- damage to structures anterior to chiasm (eye, optic nerve)
Visual field
- damage to structures posterior to chiasm (optic tracts, radiation, visual cortex)
Why test one eye at a time in visual acuity tests?
A good eye can compensate for a bad eye if both open
How would you test for visual acuity if the px had forgotten their spectacles?
Test with pinhole
How would you test for visual acuity if the px has spectacles?
Test once with, once without
How does one assess the visual field of a px?
Use your visual field (on same facing side) to compare limits of field
- EYE LEVEL MUST BE SAME
- both parties have to be looking at each others eyes
- pin should be held midway between 2 people
The left visual cortex receives input from the (left/right) retina/visual field.
Right (contralateral)
(vice versa)
What is the (i) afferent limb (ii) efferent limb of the pupillary light reflex?
i) Optic nerve
ii) Oculomotor nerve
How is a optic nerve lesion differentiated from a oculomotor nerve lesion on a pupillary light reflex?
Optic nerve lesion:
- light in affected eye → neither reflex
- light in unaffected eye → both direct and consensual reflex
Oculomotor:
- light in affected eye → only consensual
- light in unaffected eye → only direct
Describe the path of the pupillary light reflex?
Optic nerve
→ Lateral geniculate (CNII) nucleus
→ Pretectal nucleus
→ Edinger Westphal (CNIII) nucleus
→ Oculomotor nerve
→ pupil constricts
How can you tell if a px can perform visual accomodation?
Look at wall and back at pin in visual field convergence → Pupils will constrict
Movements of the eyes muscles and nerve:
UL: LR6, SR3
ML: LR6
LL: LR6, IR3
UM: MR3, IO3
MM: MR3
LM: MR3, SO4
What is the (i) afferent limb and (ii) efferent limb of the corneal reflex?
i) Trigeminal
ii) Facial
How are UMN and LMN of the face differentiated?
UMN (Hemispheric) palsy (eg. stroke)
- C/L lower lose motor
- I/L upper maintain (shared innervation from C/L)
LMN (Facial nerve) lesion(eg. Bell’s palsy):
- I/L lose motor for both upper and lower face
- C/L preserved
What is a Rinner and Weber test used for?
For deaf px to differentiate between conductive (middle/outer ear) vs sensorineural (inner ear/CN8/brainstem)
What is the Rinne’s test?
Compares air vs bone conduction in one ear
- Tuning fork on mastoid process and outside ear
- normally bone conduction would be softer
What is Weber’s test?
Compares bone conduction between both ears
- Tuning fork in middle of forehead
- should sound like in center
How is conductive hearing loss diagnosed at bedside?
Weber:
- Sound localizes to the affected ear (↓ background noise)
Rinne’s:
- Bone conduction > Air conduction (↓amplification)
How is sensorineural hearing loss diagnosed at bedside?
Weber:
- Sound localizes to the unaffected ear (affected ↓sensorineural input)
Rinne’s:
- Air conduction > Bone conduction (normal)
Which nerves are affected in a cerebellopontine angle lesion?
CNVII: Facial nerve
CNVIII: Vestibulocochlear nerve
How would a CNIX/X palsy present in an oral examination?
Uvula will be pulled to contralateral side
- by unopposed action of palatal muscles on normal side
What is the (i) afferent limb and (ii) efferent limb of the gage reflex?
i) Glossopharyngeal nerve
ii) Vagus nerve
Other than CNIX and CNX, what is tested in a gag reflex?
Medulla
How is the accessory nerve assessed?
CNIX (SCM) test:
Hold lower jaw at side and ask them to push diagonally done (repeat both sides)
How is the hypoglossal nerve assessed?
CNXII (bulbar muscles) test:
Ask to push tongue against both cheeks
Ask to stick out stick and push sideways against tongue depressor
Px asked to stick out tongue and it deviates to one side, where is the lesion?
I/L Hypoglossal nerve
What muscle protrudes the tongue and what nerve innervates it?
Geniohyoid
CNXII: hypoglossal
A lesion to the medulla affects which cranial nerves?
9, 10, 12
A lesion to the jugular foramen affects which cranial nerves?
9, 10, 12
A lesion to the carotid artery affects which cranial nerves?
12
What is a positive Rhomberg’s test?
Rhomberg’s test:
- loss of balance when shutting eyes → either proprioceptive or vestibular dysfunction
What is the physiological mechanism for side gaze?
Frontal cortex
→ C/L Paramedian Pontine Reticular Formation (PPRF) (in pons)
→ (C/L) 6th nerve → Lateral rectus
+ Medial longitudinal fasciculus (up and across) → I/L 3rd nerve → Medial rectus
What does a medial longitudinal fasciculus lesion present as?
Internuclear ophthalmoplegia
- slowness/failure to adduct both eyes in side view at the same time
Guillan-Barre syndrome is associated with _________ infection.
Campylobacter jejuni
How does Guillain Barre syndrome present?
Affects peripheral nerves:
1) Ascending numbness
2) Absent reflexes
3) Descending picture (if roots affected)
4) Miller Fisher, Bickerstaff (if brainstem)
