Nerve Root & Peripheral Nerve Disorders Flashcards
Are sensory or motor fibers usually involved first with peripheral neuropathy?
sensory
What diameter qualifies a nerve as a “large fiber” ?
They carry what types of information?
> 6 micrometer in diameter
motor
proprioception
vibration
light touch
What diameter qualifies a nerve as a “small fiber” ?
They carry what types of information?
< 6 micrometeres
sharp/dull pain, temperature, touch
Peripheral neuropathy of large fibers leads to what symptoms?
- clumsiness
- drop foot
- frequent ankle sprains
- Muscles
- atrophy
- weakness
- decreased reflexes
Peripheral neuropathy of small fibers leads to what symptoms?
- bruising or tingling
- orthostatic hypotension, gastroparesis, impotence
- Muscles
- no weakness
- normal reflexes
Identify the type of injury indicated by each of following terms:
neuropraxia
axonotmesis
neurotmesis
- neuropraxia
- compression
- axonotmesis
- crush
- neurotmesis
- cut
What are the characteristics of mononeurpathies?
focal
asymmetric neuropathy
What are the two sites of injury for median nerve neuropathy?
- Median neuropathy at the wrist
- carpal tunnel syndrome
- proximal median neuropathy
- anterior interosseus nerve syndrome
What are the classic symptoms you would expect to seen in a patient with a median nerve neuropathy?
Special tests?
-
Symptoms
- Hypoesthesia/pain in first 3 digits & lateral aspect of 4th digit
- pain is worse at night
-
Examination
- positive Tinel’s sign
- positive Phalen’s maneuver
- look for weakness in C6 innervated muscles (to make sure not missing a C6 radiculopathy/more proximal median neuropathy)
What are the major causes of median neuropathy at the wrist?
occupational
diabetes
hypothyroidism
rheumatoid arthritis
pregnancy
Treatment for median neuropathy at the wrist?
OMG/PT
wrist splint
locak injections
surgery
Proximal Median Neuropathy includes all of the symptoms seen in carpal tunnel syndrome & what additional symptoms?
- complete median sensory involvement including thenar
-
proximal median weakness (unable to flex thumb, middle & index fingers; extension of MCP joints 2&3 with flexion IP joints)
- flexor pollicis longus
- flexor digitorum profundus I & II
- pronator teres
What symptoms would you see in a patient with anterior interosseus nerve syndrome?
- weakness of flexor pollicis longus & flexor digitorum profundus 1 & 2
- pronator teres is spared
What is the largest motor branch of the median nerve? It branches distal to what muscle?
anterior interosseus
distal to pronator teres
What are the two most common locations for ulnar neuropathies?
cubital tunnel (elbow) & guyon’s canal (wrist)
What is the clinical presentation of a patient with ulnar neuropathy at the elbow?
slow onset decreased grip/pinch strength
atrophy of hyopthenar & thenar eminences (abductor digiti minimi, adductor pollicis & deep head of flexor pollicis brevis)
weakness of writst flexion & flexor digitorum profundus digits 4 & 5
impaired digital, palmar & dorsal sensory function of digit 5 & lateral half of 4
What is the clinical presentation of a patient with ulnar neuropathy at the wrist?
- Varies: motor, sensory, both → based on level of compression
- thenar and/or hypothenar motor regions
- dorsal hand ulnar sensation is spared
- no wrist flexion weakness; no ulnar deep finger flexion weakness
What are the major sites for radial neuropathy & their common causes?
- Axilla- (crutches)
- Spiral groove- (arm over bench)
- forearm - (arcade)
- wrist - (handcuffs)
Which two muscles are supplied by the radial nerve proximal to the spiral groove?
triceps & aconeus
Which two muscles are supplied by the radial nerve distal to the spiral groove but proximal to the branching of the posterior interosseus nerve?
brachioradialis & extensor carpi radialis
The posterior interosseus nerve supplies what muscles?
extersor digitorum communis
extensor indicus proprius
extensor carpi ulnaris
What features would be included to suggest an issue with posterior cord as opposed to a radial neuropathy?
deltoid & latissimus dorsi weakness
What are the symptoms of a patient with posterior interosseus neuropathy?
weak extensors
no sensory loss
What are the symptoms of a patient with superficial sensory radial neuropathy?
dorsal sensory loss over first three digits & hand