The Motor Exam
John G. Quinlan, M.D.
Department of Neurology
Overview
Tools of the trade
Manual muscle testing
Reflexes
Speed and dysmetria testing
Correlate pattern of abnormalities with
level of pathology: nerves, root, cord,
brainstem (posterior fossa), and
hemisphere.
Cases
Manual Muscle Testing
Examiner increases
force across a joint in
order to judge the
patient’s strength.
With experience you
can factor in age, sex,
and conditioning as
far as what is normal.
0-5 scale is non-linear
(3/5 is about 5% of
normal).
Manual Muscle Testing
How to avoid being
“chumped”.
Be suspicious.
Vary the amount of
force that you apply.
Pretend that you’re a
football coach.
Note variable force
generation.
Muscle Stretch Reflexes
Lower motor neuron
lesions decrease
reflexes.
Upper motor neuron
lesions increase
reflexes.
Reflexes are named
by the muscle or
tendon and are
segmental (know
nerve/root).
Muscle Stretch Reflexes
Lower motor neuron
lesions decrease
reflexes.
Upper motor neuron
lesions increase
reflexes.
Reflexes are named
by the muscle or
tendon and are
segmental (know
nerve/root).
Babinski Response
An up-going great toe
is a marker of an
upper motor neuron
lesion.
The stimulus should
be graded but
noxious.
Rapid Alternating Movements
(RAMs)
Upper motor neuron lesions cause slow
alternating movements.
Can be used for any muscle group.
The simplicity of this technique allows for
repeated testing.
Questions
Peripheral Neuropathy
Painful numbness in the feet is the most
common complaint.
Atrophy is a sign of lower motor neuron
pathology. Palpate the patient’s feet.
Palpate the extensor digitorum brevis
muscle and the intrinsic foot muscles.
Usually the ankle reflexes are absent and
there is decreased pin sensation and
position sense.
Radiculopathy
Usually asymmetrical pain (spine and
proximal), numbness and weakness.
You must know basic muscles:
Deltoid (C-5)
Triceps (C-7)
Quadriceps (L-2,3,4)
Dorsiflexors (L-5)
Plantarflexors (S-1)
Mononeuropathies
Usually asymetrical
pain (distal worse
than proximal) and
well defined sensory
loss.
You must know these
muscles:
Interossei (ulnar
nerve)
Dorsiflexors (peroneal
nerve)
Spinal Cord Lesion
Often with weak legs and strong(er) arms.
Upper motor neuron findings (increased
reflexes, bilateral Babinski responses)
predominate in the very weak legs .
Find the sensory level.
Don’t forget to ask about bladder function.
Brainstem Lesions
“D’s” (dysarthria, dizziness, diplopia,
dysmetria) get you started.
Diplopia: III nerve (big pupil, ptosis and
the eye is “down and out”.) VI nerve
(affected eye can’t abduct).
“Pa”, “Ta” and “Ka”. Names those nerves.
Remember three things about VII.
Lesions of the Cerebellum
Finger-nose-finger and toe-finger test
cerebellar hemisphere function
(ipsilateral).
Trunk or gait ataxia localize to the midline
cerebellum.
Hemispheric Lesions
Face and arm (and often leg) weakness
are on the same side.
The weakness is accompanied by “upper
motor neuron” signs:
Weak muscles have increased reflexes.
Weak muscles have slow RAMs.
Babinski response is present on weak side.
Case 1
A 24 year old man had Where would you localize
trouble walking home one the lesion(s)?
night. The next morning A) Multiple bilateral
he was unable to walk. lumbosacral
radiculopathies.
He had 3/5 strength in all
B) Lower extremity
leg muscles. His knee peripheral nerves.
and ankle reflexes were C) Thoracic cord.
increased and he had D) Primary muscle disease.
bilateral Babinski E) None of the above.
responses.
Case 2
A 24 year old man had Where would you localize
trouble walking home one the lesion(s)?
night. The next morning A) Bilateral parasagittal
he was unable to walk. motor and sensory cortex.
He had 3/5 strength in all B) Lower extremity
peripheral nerves.
leg muscles. His knee
C) Thoracic cord.
and ankle reflexes were
D) Primary muscle disease.
absent. His great toes
E) None of the above.
flexed in response to
plantar stimulation.
There was decreased
joint positions sense at
the toes and ankles.
Case 3
A 58 year old man with Where would you localize
diabetes awoke with the lesion?
paralysis of his right face, A) right pons
and left arm and leg.
B) right spinal cord
He has weakness of the C) left internal capsule
right side of his face.
D) left parasagital motor
There is 3/5 strength of cortex
his left arm and leg, and a
E) none of the above
left Babinski response.
All other aspects of his
neurological exam are
normal.
Case 4
A 62 year old woman has Where would you
had increasing low back
pain for the last two localize the lesion?
weeks. The pain has A) Right tibial nerve.
intensified in the last few B) Left parasagittal
days and now radiates to motor cortex.
her right buttock.
C) Right L-5 root.
She is unable to rise up
on her toes on the right D) Right S-1 root.
side. Her right ankle E) Left pons.
reflex is absent.
Otherwise, her
neurological exam is
normal.
Questions