EMG pathology Flashcards
____ is a pathologic process affecting the nerves at a root level.
Radiculopathy
Radiculopathy most commonly presents as: (3, in descending order)
- pure sensory complaints
- sensorimotor
- pure motor complaints
(this is due to the larger size of sensory fibers, rendering them more prone to injury)
Most common cause of radiculopathy?
- in adults <50yoa?
- in adults >50yoa?
- Herniated nucleus pulposis
- Spinal Stensosis
Name the 7 uncommon causes of radiculopathy:
“Hi Madam”
H - herpes zoster
I - inflammatory (TB, Lyme disease, HIV, syphilis, cryptococcus, and sarcoidosis)
M - Metastasis
A - Arachnoiditis
D - DM
A- Abscess
M - Mass: meningioma, neurofibroma, leukemia, lipoma, cyst, hematoma
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
C5
Reduced reflex: Biceps brachii
Weakness: Elbow flexion
Numbness/parasthesia: Lateral arm
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
C6
Reduced Reflex: Brachioradialis
Weakness: Elbow Flexion
Numbness/Parasthesis: Lateral forearm
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
C7
- reduced reflex: Triceps brachii
- Weakness: elbow extension
- Numbness/parasthesias: middle finger
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
C8
- Reduced reflex: none
- Weakness Finger flexion
- Numbness/parasthesias: Medial forearm
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
T1
Reduced reflex: none
Weakness: Finger adduction
Numbness/parasthesia: medial elbow
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
L4
Reflex reduced: patella tendon
Weakness: knee extension
Numbness/Parasthesias: Medial ankle
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
L5
Reduced reflex: Lateral hamstring
Weakness: Hall extension
Numbness/parasthesias: Dorsal foot
Clinical presentation of Radiculopathy: Name 1. reflex reduced 2. Weakness 3. Numbness/parasthesia
S1
Reduced reflex: Achilles tendon
Weakness: plantar flexion
Numbness/parasthesias: Lateral ankle.
In Radiculopathies:
SNAP:
CMAP:
SNAP: normal if lesion is located proximal to dorsal root ganglgion
CMAP: normal or reduced amplitude. This lesion is distal to the motor neuron cell body. It can be normal if the injury is purely demyelinating, incomplete, or reinnervation has occurred.
C2-3 C3-4 radiculopathy is a ____ diagnosis
clinical
No discrete myotomal patterns
C3 and C4
C2/3, C3/4 HNP
radiculopathy:
- Innervates:
- Patient may complain of:
- C2 and C3 nerve becomes:
- posterior and lateral scalp
- headaches
- greater and lesser occipital nerve
C5 (C4-5 HNP) myotome: 9
Rhomboids
Deltoid (5/6)
Biceps (5/6)
Supraspinatus (5/6)
Infraspinatus (5/6)
Brachialis (5 only)
BR (5/6)
Supinator (5/6)
Paraspinals (5-8)
C6 (C5-6 HNP) myotome: 10
Deltoid (5/6)
Biceps (5/6)
BR (5/6)
Supraspinatus (5/6)
Infraspinatus (5/6)
Supinator (5/6)
PT (6/7)
FCR (6/7)
EDC (6/7)
Paraspinals (5-8)
C7
C6-7 HNP
Myotome: 5
PT (6/7)
FCR (6/7)
EDC (6/7)
Triceps (7/8)
Paraspinals (5-8)
C8
C7-T1 HNP
Myotome: 8
Triceps (7/8)
FCU
FDP
ADM
FDI
PQ
APB
Paraspinals
L2/3/4 roots
L1/2, L2/3, L3/4 HNP
Myotome: 7
Iliopsoas
Iliacus
Gracilis
adductor longus
vastus medialis
TA
paraspinals (all)
Difficult to distiguish between radiculopathy and alternate lesions due to only two peripheral nerves
Root: L5
Posterolateral L4/5 HNP
Myotome: 9
gluteus maximus
gluteus medius
TFL
TA (2-5)
medial hamstring
TP
PL
Paraspinals
Root: S1
Posterolateral L5/S1 HNP
Myotome: 8
gluteus maximus (L5/S1)
gluteus medius (L5/S1)
TFL (L5/S1)
MG (L5/S1)
Medial hamstring(L5/S1)
PL (L5/S1)
TP (L5/S1)
Paraspinals
Root: S2/3/4
Etiology: iatrogenic, cauda equina, spinal stenosis
Myotome: 2
needle exam of:
Other reflexes: 4
Myotome: Abductor Hallucis, ADQ
Needle exam: external anal sphincter
Reflexes: bulbocavernosus reflex, anal wink, external sphincter tone, bowel and bladder function
Name the 8 dual innervated muscles and their innervation.
- Pectoralis major: Medial pectoral, lateral pectoral n
- Brachialis: musculocutaneous n, radial n
- FDP: Median n (AIN), Ulnar
- Lumbricals: Median, ulnar
- Flexor pollicis brevis: median, ulnar
- Pectineus: Femoral Nerve, Obturator Nerve
- Adductor magnus: Sciatic (tibial portion), Obturator
- Biceps femoris: Sciatic (tibial portion), Sciatic (peroneal)
Chronology of findings: radiculopathy:
O days: 4
4 days:
1 week:
2 weeks:
3 weeks:
5-6 weeks:
6months-1yr:
0 days: decreased recruitment, decreased recruitment interval, prolonged F-wave, Abnormal H-reflex (S1 radiculopathy)
4 days: Decreased CMAP amplitude (~50% compared to opposite side)
1 week: abnormal spontaneous activity if occurs first in the paraspinals. They can be normal if they become reinnervated or if the posterior prinary rami are spared (they can be the only abnormal finding 10-30% of the time)
2 weeks: abnormal spontaneous activity beginning in the limbs
3 weeks: abnormal activity present in paraspinals and limbs
5-6 weeks: reinnervation
6months-1yr: increased amplitude from reinnervated motor unit.
_____ is the pathologic process typically occurring distal to the DRG and proximal to the peripheral nerves. Abnormalities can appear diffuse and will not follow any particular dermatomal or myotomal distribution.
plexopathy
3 etiologies of plexopathy
- trauma (traction, transection, obstetrical injuries, compression, hemorrhage)
- cancer (tumor, radiation therapy)
- idiopathic (neuralgic amyotrophy)