PNS1 Flashcards
Peripheral n- CT binding
- epineurium- covers whole n
- perineurium- fascicles
- endoneurium- individual fibers
peripheral n- anatomy
- myelinated- fast conducting; saltatory conduction
- unmyelinated- slow conducting (cannot be asses on EMG)
pain- fiber types
-smaller, unmyelinated fibers
position, touch, pressure, positional sense, vibratory sense- fiber types
-larger, myelinated fibers
peripheral n injury- pathological processes
- wallerian degeneration (severed n)
- segmental demyelination (GB)
- axonal degeneration
Radiculopathy
- n root dysfxn- caused by structural (discs, osteophytes, tumors) or non-structural (DM, infections)
- C5-6= C6 n root compression
- C6-7= C7 n root compression
- L4-5= L5 n root compression
- L5-S1= S1 n root compression
C5- pain, sensory, weakness, DTR loss
- scapula, shoulder
- lateral arm
- should abd
- biceps
C6- pain, sensory, weakness, DTR loss
- scapula, shoulder, prox arm
- 1-2 digit, lateral arm
- shoulder abd, elbow flex
- biceps
C7- pain, sensory, weakness, DTR loss
- scapula, shoulder, elbow/forearm
- 3rd digit
- elbow ext, wrist ext, finger ext
- triceps
C8- pain, sensory, weakness, DTR loss
- scapula, shoulder, medial forearm
- 4-5 digit
- finger abd, finger flex
- finger flexors
L4- pain, sensory, weakness, DTR loss
- antlat thigh, knee, medial calf
- medial calf
- hip flex, knee ext
- patella
L5- pain, sensory, weakness, DTR loss
- dorsal thigh, lat calf
- lat calf, dorsum foot
- hamstrings; foot dorsiflex, inversion, eversion
- none
S1- pain, sensory, weakness, DTR loss
- post thigh, post calf
- postlat calf, lat foot
- hamstrings, foot plantarflex
- achilles
Dermatome map- hallmarks to note
- C6- thumb/index finger
- C7- middle finger
- C8- 4/5 finger
- T1- medial forearm
- T4- nipple line
- T10- umbilicus
- L1- inguinal
- L4- medial calf
- L5- lateral calf
Peripheral neuropathy- classification
- Mononeuropathy- single n; sensory loss; weakness only in specific m’s
- Polyneuropathy- diffuse, symmetrical dz (motor, sensory, or both); stocking/glove sensory loss; distal weakness; hypo or areflexia
- Mononeuropathy multiplex- focal involvement of 2 or more n’s; can occur in systemic disorders (DM, vasculitis)
Peripheral neuropathy- sensory sx’s
- Negative- loss of sensation
- Positive:
- paresthesias (pins and needles)- large myelinated fiber dz
- pain- small unmyelinated fiber dz- burning sensations, dysesthesia (gentle touch), hyperalgesia (lowered threshold to pain), hyperpathia (pain excessively felt)
Peripheral neuropathy- motor sx’s
- distal weakness
- cramps
- m fasciculations
- atrophy
- dec DTRs
- reduced tone
Peripheral neuropathy- sensory sx- large fiber? lower fiber?
Large myelinated fibers- impairment of: -light-touch -2-pt discrimination -vibration -joint position sense Small unmyelinated fibers- dec pain and T
CNS (vs Peripheral patterns)- motor system- paresis, tone, bulk, fasciculations; reflexes, sensory loss
- UMN:
- paresis- patterns
- tone- spastic
- Reflexes:
- DTRs- hyperactive
- plantar- babinski sign
- Sensory loss- patterns
PNS (vs CNS)- motor system; paresis, tone, bulk, fasciculations; reflexes, sensory loss
- LMN:
- paresis- distal
- tone- flaccid
- bulk- atrophic
- fasciculations- sometimes
- DTRs- hypoactive
- plantar- absent
- sensory loss- hands and feet
Brachial Plexopathy- etiology
- compression/stretch (CABG)
- infl/idiopathic (parsonage-turner)
- radiation injury (upper trunk, lateral cord, painless)
- neoplastic (breast, lung- medial cord, painful)
- traumatic injury
- ischemia (diabetic- lumbar)
Upper limb entrapment neuropathies
- median
- ulnar
- radial
median n- site of compression
- carpal tunnel syndrome
- ant interosseous
- pronator teres syndrome
median n- sx’s
- sensory- medial palmar surface of lower forearm and palm, thenar eminence (thumb base), thumb and adj 2 and 1/2 fingers
- carpal tunnel syndrome- pain, numbness spread downward from wrist
Pronator Syndrome- clinical features
- dull ache- proximal forearm
- pain exacerbation w forearm pronation
- easy fatigue of forearm m’s
- numbness of 2-3 fingers
- absence of nocturnal awakening (vs carpal tunnel syndrome)
Anterior interosseous syndrome
-Cant make Ok sign
Ulnar mononeuropathy- common sites
- axilla
- elbow- medial epicondyle and olecranon
- cubital tunnel- tendinous arch of FCU (flexor carpal ulnaris)
- wrist- Guyon’s canal
Ulnar mononeuropathy- sx’s
-froment sign (adductor pollicis)
radial mononeuropathy- common sites
- axilla- crutch palsy
- humerus/spiral groove- saturday night palsy (most common)
- supinator (posterior interosseous branch)
- wrist (superficial radial sensory branch)- handcuffs- numbness back of thumb
radial n- sx
-wrist drop- paresis of extensor m’s of wrist, finger, and thumb
Saturday night palsy
(radial n- spiral groove)
-weakness of wrist and finger ext
lower limb entrament neuropathies
- sciatic
- peroneal (most common)
- lateral femoral cutaneous
Sciatic n- predisposing factors, clinical features
- intramuscular injections; fracture dislocations
- pain down lateral thigh, footdrop, absent ankle jerk
Peroneal n- predisposing factors, clinical features
- fibular neck- compression
- leg crossing, squatting
- foot drop, weak evertors, sensory loss in dorsum of foot
lateral femoral cutaneous n- predisposing factors, clinical features
- inguinal l
- tight clothing, weight gain
- sensory loss in lateral thigh
Peroneal mononeuropathy- where? sx?
fibular head
- weakness of foot dorsiflexion and eversion (FOOT DROP)
- weakness of toe ext
- sensory loss dorsum of foot
