Lecture 8: Peripheral Nervous System Disorders Flashcards
UMN lesion
* What are reflexes like? (2)
* What is tone like (2)
* What happens to babinski sign?
* What happens to muscles innervates from these nerves
Reflexes are normal or hyperactive
Tone = spasticity or hypertonicity
Positive babinski sign
Muscle atrophy
LMN
* what are reflexes like? (2)
* What is tone like (2)
* What is babinski sign like?
* What happens to muscles innervated by these nerves
Reflexes are normal or hypoactive
Tone = hypotonicity or flaccidity
Negative babinski sign
muscle atrophy
Spinal region segmental signs occur when what two areas are compromised?
* sensation is lost in what kind of pattern?
* Muscle power is lost in what kind of pattern
* What happens to phasic stretch reflex?
Compromised:
* Nerve roots
* Spinal nerves
Sensation is lost in a dermatomal pattern
Muscle power is lost in a myotomal pattern
Decreased or lost phasic stretch reflex
* where hyporeflexive w/ LMN
Nerve root vs peripheral nerve PNS
Combined sensory and motor monosynaptic stretch reflex
reflex requires sensory and motor to come together and work
* goes to the SC then back to motor units (skips brain)
This is differentiating CNS from PNS
Spinal region/vertical tract signs:
* Where is snsation lost?
* What happens to tone below the level of lesion?
* what happens to muscle power
* if the corticospinal tract is involved what two things hapens?
Sensation is lost below level of lesion (NOT AT LEVEL OF LESION)
KNOW: They’re also going to lose decending control of BP, pelvic viscera and thermoregulation
hypertonia/spasticity
Decrease in muscle power
corticospinal tract invovled = babinski / clonus
Peripheral region lesions produce deficits in the distribution of a peripheral nerve
* What kind of distribution is sensation lost in?
* What is muscle power loss distribution?
* Are there vertical tract signs?
* What happens to phasic stretch reflex? (think patellar reflex)
In a peripheral nerve distribution loss of sensation
Loss/decrease in muscle power in a peripheral nerve distribution
No vertical tract signs - SC unaffected here
Decreased or lost phasic stretch reflex
Dermatomes
L2 spinal cord injury will the pt have hip flexion?
Yes, its loss below the level of the lesion
knowledge check: our damage is in a dermatomal distribution. What is likely injured a peripherl nerve or a spinal nerve
spinal nerve presents in a dermatomal fashion
Complete transection/serverd neuron?
Neurotmesis
Neuropraxia means
Compression
crush or stretch injury of nerve
axonotmesis
Case: A tennis player fell on her shoulder during a tennis match. Her shoulder was tractioned away from her head resulting in a traumatich stretch on the C5 and C6 nerve roots
* Which movements of the arm will likely be weak
* Where are on her arm will she have altered sensation?
* What type of damage in this
Elbow flexion/Wrist extension and down
* for dermatomes / myotomes its at the level of the lesion. This makese sense, if the spinal nerve is impinged it will go out in that pattern
Altered sensation on the side of the arm (learn new dermatomes I guess)
Axonomesis - think stretch
In a spinal cord injury where is the pathology
In a Spinal nerve injury where is the pathology
SC = below level of lesion
Spinal nerve = pathology at level of lesion
* spinal nerves go streaight out to innervate what they need. This makes sense
Case: A 32 year old computer programmer developed 2 months of worsening tingling and numbness in his left fith digit, in the medial aspect of his left fourth digitm and along the medial surface of his left hand and forearm. Symptoms were worse upon awakening in the morning, and were exacerbated after resting his elbows on a hard surface
* which nerve is involved
* What type of dmaage
* Where is the damage coming from?
Nerve = ulnar n
Type of damage = neuropraxia (hes resting his arm down)
Damage is coming from the nerve (peripheral nerve)
Knowledge checK: stretch to nerve = axonomesis
What records the activity of the muscle at rest, with voluntary movement and with e-stim
* looking for damage related to the striated muscle (skeletal muscle)
* EX = myopathy - damage to the muscle or neuromuscular junction
EMG
Measures the conduction time and amplitude of an electrical stimulus along a peripheral nerve (sensory or motor nerves)
* looking for damage to the nerve cell body or the nerve axon
* EX: peripheral nerve injury
Nerve conduction velocity (NCV)