Clinical assessment quiz 2 Flashcards
Why neurological testing?
test coordination of afferent/efferent impulses (to/away from CNS)
regions of body supplied by spinal nerves
8 cervical spinal nerves
12 thoracic spinal nerves
5 lumbar spinal nerves
5 sacral spinal nerves
myotomes and dermatomes
spinal nerves have
motor fibres
sensory fibres
motor fibres of spinal nerves
innervate certain muscles
sensory fibres of spinal nerves
innervate certain areas of skin
dermatome/myotome pattern – is it consistent between different people?
despite slight variations, pattern distribution is relatively consistent b/w people.
Dermatome =
skin area innervated by sensory fibres of a single nerve root
Dorsal vs Ventral roots of spinal nerves
Dorsal root = Afferent fibres enter CNS via “
Ventral root = Efferent fibres exit CNS via “
dermatome vs dorsal roots
bilateral area of skin associated with pair of Dorsal Roots from spine
why is dermatome region important?
pain following dermatome region may indicate spinal damage or neurological stenosis
E.g. Compressed spinal nerve may show as pain elsewhere (E.g. @ Dermatome region)
other clinical significances of DERMATOMES
finding site of damage to spine
E.g.
Viruses that affect spinal nerves – E.g. Herpes Zoster
“MIGRATES ALONG SPINAL NERVE TO AFFECT ONLY AREA OF SKIN SERVED BY THAT NERVE”
“Symptoms are usually unilateral but in the immune suppressed, they are more likely to become bilateral and symmetrical, meaning that the virus is present in both ganglia of a dorsal root ganglion pair.”
MYOTOMES
group of muscles innervated by the Motor fibres of a single nerve root (VIA VENTRAL ROOT OF SPINAL NERVE)
DEEP TENDON REFLEXES
assess the functioning of nerve or nerve roots supplying the reflex
how is DTR caused?
stretching of muscle spindle
” synapses via sensory neurons to spinal cord then back via motor neurons
What happens when DTR is absent?
spinal cord, nerve root, peripheral nerve or muscle has been damaged
when response is weak/abnormal – indicates disruption of sensory and/or motor neurons
CLONUS
“When reflexes are very brisk, clonus is sometimes seen. This is a repetitive vibratory contraction of the muscle that occurs in response to muscle and tendon stretch.”
clonus = “muscular spasm involving repeated, often rhythmic, contractions.”
DTR ratings/scale
0: absent reflex
1+: trace, or seen only with reinforcement
2+: normal
3+: brisk
4+: nonsustained clonus (i.e., repetitive vibratory movements)
5+: sustained clonus
normal vs. abnormal DTR reflex
Deep tendon reflexes are normal if they are 1+, 2+, or 3+
Reflexes rated as 0, 4+, or 5+ are usually considered abnormal.
clonus, hyperreflexia
In addition to clonus, other signs of hyperreflexia include spreading of reflexes to other muscles not directly being tested and crossed adduction of the opposite leg when the medial aspect of the knee is tapped.
hyperreflexia
Hyperreflexia happens when your muscles have an increased or overactive reflex response.
What is being tested during DTR test?
DTR reflex diminished during problems in
A) muscles
b) sensory neurons
c) lower motor neurons
d) NMJ
e) upper motor neurons (acute lesions)
f) joints (joint disease = mechanical factors)
abnormally increased reflexes =
upper motor neuron nerve lesions
DTR reflexes variables of influence
age
metabolism
thyroid dysfunction
electrolyte imbalances
mental state (e.g. anxiety)
why it is important to repeat the test multiple times (5-6 times)
to ensure consistent response
(inconsistent response can indicate pathology – E.g. fading response due to nerve root lesion)
