final exam Flashcards
what are the 4 causes of peripheral nerve lesions?
- compression (internally ie: bony callus/HT muscles; externally ie: crutches)
- trauma (crushing or wound)
- systemic disorders (lepsory)
- systemic edematous conditions (pregnancy, hypothyroidism, kidney & heart failure)
at what rate does a nn regenerate per day?
1-2 mm per day
1/2 - 3/4 per week and 1 1/4 - 2 1/4 per month
what is the prognosis for the 3 clasifying nerve injuries (neuropraxia, aconotmesis & neuromesis)
neuropraxia: good
aconotmesis: good
neurotmesis: poor
first degree classification of nn injury
neuropraxia
second degree classification of nn injury
aconotmesis
third degree classification of nn injury
neurotmesis
what causes Neuropraxia injuries
compression of a nn causing local conduction block, no structural damage to the axon or the tissue distal to the lesion
what causes anconotmesis injuries
prolonged, severe compression of a nn that will cause a lesion at the site of compression, followed by degeneration of the axon distal to the injury; endoneurial tube remains in tact
what causes neurotmesis injuries
injury involves severing of the nn trunk; including the endoneurial tube. results in degeneration of the nn, regeneration may be difficult due to scar tissue build up on lesion site
how are Neurotmesis nn injuries repaired?
usually surgery
what is hyperesthesia?
abnormal increase to sensitivity
what is dysesthesia?
abnormal sense of touch
how will symptoms present with partial and complete nerve lesions when edema is present
complete: edema present initially, due to injury. damage to autonomic fibers so edema remains until regeneration & vasomotor function returns.
partial: edema present initially, due to injury. less edema than with complete. because there is some local mm function, assists with lympathic return
how will symptoms of altered tissue health present with partial and complete nerve lesions
complete: loss of autonomic function affects skin, hair, nails. fragile tissue, dystrophic & easily injuried. LOSS of piloerection. loss of sweating over area of denervation
partial: tissue changes, not as severe as complete. an INCREASE piloerection over area of denervation
how will symptoms of motor function present with partial and complete nerve lesions
complete: flaccidity; mm wasting within 3 wks. spontaneous contraction of mm fibers within few weeks (fibrillations). LACK or DIMINISHED reflex
partial: mm weakness, diminished tendon reflex
how will symptoms of holding patterns present with partial and complete nerve lesions
complete: drop foot with sciatic nn lesion, drop wrist with radial
partial: less apparent since some fibers are innervated. ex: partial radial nn lesion will have finger drop rather than full wrist drop
how will symptoms of contractures present with partial and complete nerve lesions
complete: affected mm unable to exert force on joint they cross. contractures will develop in antagonists as they draw into shorter portion
partial: same as complete. less severe than complete because there is some opposition to antagoinist
how will pain symptoms present with partial and complete nerve lesions
complete: pain variable. may be decreased or altered sensation
partial: likely area of hyperesthesia (abnormal increase to sensitivity) and dysesthesia (abnormal sense of touch)
how will scar tissue symptoms present with partial and complete nerve lesions
complete&partial: present at lesion site; could interfere with healing/regeneration process
Increased piloerector response is associated with which type of nerve lesion, complete or partial? and how is the other affected?
partial nn lesion.
complete is decreased response
What category of classification does Carpal Tunnel Syndrome fall under?
Neuropraxia: Compression Syndrome
- Compression of the Medial Nerve as it passes through the carpal tunnel at the wrist
What category of classification does Piriformis Syndrome fall under?
Neuropraxia: Compression Syndrome
- Piriformis syndrome is when the piriformis compresses the sciatic nerve.
What category of classification does Thoracic Outlet Syndrome fall under?
Neuropraxia: Compression Syndrome
- Compression of the Brachial Plexus and artery between:
- the middle and anterior scalenes (anterior scalene syndrome)
- the coracoid process and the pec minor muscle (pec minor syndrome)
- the clavicle and 1st rib (costoclavicular syndrome)
What are examples of external causes of compression in nerve lesions?
pressure from crutches, splints, backpack straps