Neurological Flashcards
upper and lower limb examinations can be split into what categories?
tone
power
reflexes
sensation
when you see hypotonia in a patient, it’s due to?
breach/disruption in the spinal segmental reflex arc and the simple spinal reflexes are not functioning
LMN (lower motor neuron) lesion
The impulses from the upper motor neurons have a _______ effect on the lower motor neurons.
inhibitory
If the higher cerebral control is disrupted, as in an UMN lesion, muscle tone is exaggerated you will experience?
hypertonia
sometimes spasticity
where do you test for tone in the upper limb?
shoulder
elbow
wrist
what scale is used for noting strength/power in muscle?
Medical Research Council (MRC) Muscle Power scale.
what is 0/5 on the MRC muscle power scale?
no movement
what is 1/5 on the MRC muscle power scale?
Barest flicker of movement of the muscle, though not enough to move the structure to which it’s attached
what is 2/5 on the MRC muscle power scale?
Voluntary movement which is not sufficient to overcome the force of gravity.
what is 3/5 on the MRC muscle power scale?
Voluntary movement capable of overcoming gravity, but not any applied resistance
what is 4/5 on the MRC muscle power scale?
Voluntary movement capable of overcoming “some” resistance
what is 5/5 on the MRC muscle power scale?
Normal strength
what signs can be used to indicate more subtle descriptions of power?
+/-
how to assess power
resist the movement by applying an opposing force and estimate the power of the contracting muscle/s. You will also need to isolate and stabilize the joint to accurately measure the power
where to assess for power in the upper limb?
shoulder abduction and adduction
elbow flexion and extension
wrist flexion
are most of the myotactic reflexes monosynaptic or multisynaptic?
monosynaptic
When the tendon of a muscle is tapped with a tendon hammer, why does it elicit a reflex?
causes stretching of the muscle spindles > stimulus travels to spinal cord > stimulates efferent motor neurons in anterior grey columns (horns) > involuntary contraction of the main muscle
how to apply reinforcement to individuals to elicit reflexes
clench the teeth or squeeze an object in the contralateral (other) hand while you directly test the reflex on the limb to be tested
law of reciprocal innervation
afferent nerves responsible for flexor reflex muscle action must have branches to synapse with the extensor motor neurons of the same limb to inhibit the extensor muscle contraction
abnormally exaggerated myotatic reflexes lead to a clinical picture of?
upper motor neuron lesion
If there is disorder in any of the components of the reflex arc (muscle spindles, afferent sensory neurones, efferent motor neurones and the effector organs, what will happen to the reflexes?
areflexia (complete absence)
areflexia is suggestive of?
lower motor neuron lesion
how to test for a reflex
ensure that the relevant limb is completely relaxed, you will then attempt to elicit the reflex by tapping the relevant tendon with a tendon hammer
what reflexes are there to test in the upper limb?
Biceps (C5, C6)
Triceps (C7, C8)
Suprinator (C6)
define dermatome
area of skin supplied by a single spinal nerve root of the spinal cord segment
define myotome
group of muscles innervated by the ventral root a single spinal nerve
on the skin of the upper limb do dermatomes overlap?
yes considerably
where is there no overlap of dermatomes?
across axial lines
how many dermatomes need to be affected in order to detect a significant sensory loss?
three adjacent dermatomes
where to test for sensation in the upper limb? pair them with the relevant nerve root
Shoulder (C4) Lateral aspect of the arm (C5) Lateral aspect of forearm (C6) Middle finger (C7) Little finger (C8) Medial aspect of forearm (T1) Axilla (T2)
musculocutaneous nerve supplies what dermatomal segment?
C5, C6, C7
median nerve supplies what dermatomal segment?
C6-8, T1
radial nerve supplies what dermatomal segment?
C5-C8, T1
ulnar nerve supplies what dermatomal segment?
C7, C8, T1
what do you test for tone in the lower limb?
hip
knee
ankle
clonus
what do you test for power in the lower limb?
Hip flexion and extension
Knee flexion and extension
Ankle dorsiflexion and plantarflexion
what reflexes do you test in the lower limb? pair with relevant spinal roots
Patellar (L2, L3, L4)
Achilles (S1, S2)
where do we test for sensation in the lower limb? pair with relevant spinal roots
Lateral aspect of thigh (L2)
Lower medial aspect of thigh (L3)
Medial aspect of leg, medial foot and great toe (L4)
Lateral side of leg, mid dorsum of foot and middle three toes (L5)
Little toe, lateral foot and sole of foot (S1)
Back of upper leg and thigh (S2)
posterior rami nerve supplies what dermatomal segment?
L1-L3
S1-S3
obturator nerve supplies what dermatomal segment?
L2, L3, L4
femoral nerve supplies what dermatomal segment?
L2, L3, L4
common fibular (part of sciatic) nerve supplies what dermatomal segment?
L4, L5, S1, S2
tibular (part of sciatic nerve) nerve supplies what dermatomal segment?
L4, L5, S1, S2, S3
