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RADIAL NEUROPATHY
DR AHAMED SUBIR H
Radial Nerve
• Originates as the terminal branch of the
posterior cord of the brachial plexus:
– roots from C5, 6, 7, 8, &...
Course of Radial Nerve
• Largest terminal branch of posterior cord
• Enters posterior aspect of humerus through lower
tria...
Course of Radial Nerve
• Comes to lie in distal part of spiral groove with
profundi brachii artery
– Beneath lateral head ...
Course of Radial Nerve
• In anterior compartment of arm lies between
brachialis and brachioradialis
– 1-3 accessory branch...
Course of Radial Nerve
• Enters the forearm anterior to lateral epicondyle
– More specifically over articulation between c...
Course of Superficial Radial Nerve
• Runs over supinator,PT and FDS
• Lies under BR with radial artery on its ulnar side f...
INNERVATIONS
Cutaneous Innervation
• Posterior cutaneous nerve of arm
• Inferior lateral cutaneous nerve of arm
• Posterior cutaneous n...
Motor Innervation
• Muscular branches of radial nerve above elbow:
– Triceps
– Anconeus
• After this, it wraps around hume...
• Superficial branch- superficial radial sensory
nerve
• Descends distally into forearm over radial
bone –sensation over
–...
Motor Innervation
• Deep branch- deep radial motor branch below
elbow:
– ECRB (varied innervation: superficial or PIN)
– S...
Posterior Interosseous Nerve
• Gains access to posterior forearm by diving
posterior and laterally through ligament of
Fro...
Posterior Interosseous Nerve
• After exiting the supinator divides into deep
and superficial muscular branches
– Superfici...
CLINICAL SITUATIONS
RADIAL NEUROPATHY AT SPIRAL
GROOVE
• Most common radial neuropathy
• Why? Bcoz Juxtraposed to humerus
• Causes-prolonged i...
• Wrist drop and finger drop( EI,EDC,ECU,ECRL)
• Mild weakness of supination( supinator)
• Elbow flexion weak(brachioradia...
RADIAL NEUROPATHY AT AXILLA
• From prolonged compression-crutches
• There is additional weakness in extension
(triceps and...
POSTERIOR INTEROSSEOUS
NEUROPATHY
• Entrapment in arcade of Frohse
• Other causes-ganglion, cyst ,tumours
• Similar to spi...
SUPERFICIAL RADIAL SENSORY
NEUROPATHY
• Superficial location
• Cheiralgia paraesthetica
• Tight fitting watches,bandss,bra...
RADIAL TUNNEL SYNDROME
• Isolated pain and tenderness in extensor
forearm
• thought to result form compression of PIN
• No...
Differential diagnosis of wrist drop
• PIN
• Radial nerve in spiral groove
• Radial nerve in axilla
• Posterior cord
• C7 ...
• C7 –extend wrists and fingers with sparing of
non radial C7 muscles
• If severe C7 radiculopathy-weakness of
pronator te...
DD
ELECTROPHYSIOLOGIC EVALUATION-
NCS
ELECTROPHYSIOLOGIC EVALUATION-
NCS
RADIAL MOTOR STUDY
• EIP muscle –G1- 2 finger breadth proximal to
ulnar styloid
• G2 – ...
RADIAL MOTOR STUDY
Recommended NCS protocol for Radial
neuropathy
• Radial motor study-EI –stimulating forearm, elbow,below
and above spiral ...
Results
• PIN(axonal)- normal superficial radial SNAP, low
amplitude distal radial CMAP
• PIN(demyelinating)- normal super...
Technical considerations
• Placing G1 over EI-initial positive deflection-
volume conducted potentials from nearby radial
...
Demyelinating lesion in spiral groove
RADIAL SENSORY STUDY
• Superficial sensory radial is easy to stimulate
& record
• G1 – extensor tendons of thumb
• G2 – 3 ...
RADIAL SENSORY STUDY
Radial SNAP
• 3 situations with normal SNAP( when clinically
sensory signs +)
– Hyper acute axonal loss
– Lesion proximal to dorsal ro...
Wrist drop with normal SNAP-DD
• PIN
• Lesions caused by proximal demyelination(radial
groove and axilla)
• C7 radiculopat...
ELECTROPHYSIOLOGIC EVALUATION-
EMG
ELECTROPHYSIOLOGIC EVALUATION-
EMG
• To distinguish
• PIN
• Lesion inradial groove and axilla
• C7 radiculopathy
• CNS les...
EMG PROTOCOL
• Atleast 2 PIN muscles( EI,ECU,EDC)
• atleast 1 radial innervated muscle proximal to
bifurction of main radi...
• In pure demyelinating lesions with conduction
block only abnormality will be decreased
recruitment of MUAPs in weak musc...
THANK YOU
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
Radial neuropathy and electrophysiology
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Radial neuropathy and electrophysiology

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about radial nerve anatomy,course,clinical syndromes,nerve conduction study and EMG protocol

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Radial neuropathy and electrophysiology

  1. 1. RADIAL NEUROPATHY DR AHAMED SUBIR H
  2. 2. Radial Nerve • Originates as the terminal branch of the posterior cord of the brachial plexus: – roots from C5, 6, 7, 8, & T1. – Largest branch of brachial plexus
  3. 3. Course of Radial Nerve • Largest terminal branch of posterior cord • Enters posterior aspect of humerus through lower triangular interval – Teres major (superior) – Long head triceps (medial) – Humerus (lateral) • Gives posterior cutaneous nerve of arm in axilla
  4. 4. Course of Radial Nerve • Comes to lie in distal part of spiral groove with profundi brachii artery – Beneath lateral head of triceps and proximal to origin of medial head • Gives branches to triceps, anconeus and inferior lateral cutaneous nerve of arm • Through lateral intermuscular septum 10-12cm above lateral epicondyle
  5. 5. Course of Radial Nerve • In anterior compartment of arm lies between brachialis and brachioradialis – 1-3 accessory branches to brachialis – Large branch to BR (sometimes this branch given by superficial radial below elbow) • ECRL generally innervated proximal to elbow joint
  6. 6. Course of Radial Nerve • Enters the forearm anterior to lateral epicondyle – More specifically over articulation between capitulum and radial head • ECRB innervated distal to elbow joint either PIN or superficial branch • At some point 3cm above or below divides into: – Superficial radial – PIN
  7. 7. Course of Superficial Radial Nerve • Runs over supinator,PT and FDS • Lies under BR with radial artery on its ulnar side from 1/3 of the way down forearm • Passes posteriorly through tendon of BR proximal to radial styloid • Passes over tendons of snuffbox • Terminates as cutaneous branches to dorsum of hand and lateral 3.5 digits short of nailbeds
  8. 8. INNERVATIONS
  9. 9. Cutaneous Innervation • Posterior cutaneous nerve of arm • Inferior lateral cutaneous nerve of arm • Posterior cutaneous nerve of forearm • Superficial branch of radial nerve
  10. 10. Motor Innervation • Muscular branches of radial nerve above elbow: – Triceps – Anconeus • After this, it wraps around humerus in the spinal groove – Brachoradialis – ECRL • Then after 3 -4 cm after lateral condyle bifurcates
  11. 11. • Superficial branch- superficial radial sensory nerve • Descends distally into forearm over radial bone –sensation over – Lateral dorsum of hand – Part of thumb – Proximal dorsal phalanges of index,middle and ring finger • It is palpable over extensor tendons of thumb
  12. 12. Motor Innervation • Deep branch- deep radial motor branch below elbow: – ECRB (varied innervation: superficial or PIN) – Supinator • After it enters supinator muscle • PIN: – Superficial • EDC, ECU,, EDM – Deep • APL, EPL, EPB, EI – It has sensory (not a pure motor)
  13. 13. Posterior Interosseous Nerve • Gains access to posterior forearm by diving posterior and laterally through ligament of Frohse and the interval between the two heads of supinator • Arcade of Frohse is a fibrous arch originating lateral epicondyle superior part of superficial layer of supinator
  14. 14. Posterior Interosseous Nerve • After exiting the supinator divides into deep and superficial muscular branches – Superficial • EDC, ECU, EDM – Deep • APL, EPL, EPB, EI
  15. 15. CLINICAL SITUATIONS
  16. 16. RADIAL NEUROPATHY AT SPIRAL GROOVE • Most common radial neuropathy • Why? Bcoz Juxtraposed to humerus • Causes-prolonged immobilisation ( saturday night palsy) -strenous muscle effort -# humerus - infarction from vasculitis There is compression and demyelination of radial nerve
  17. 17. • Wrist drop and finger drop( EI,EDC,ECU,ECRL) • Mild weakness of supination( supinator) • Elbow flexion weak(brachioradialis) • Elbow extension is spared • Sensory disturbance only in the distribution of superficial radial sensory nerve • In isolated radial neuropathy- ulnar & median spared. • Test in neutral position- finger abduction by placing hand over a flat surface
  18. 18. RADIAL NEUROPATHY AT AXILLA • From prolonged compression-crutches • There is additional weakness in extension (triceps and anconeus) and • sensory disturbance along arm and forearm (posterior cutaneous nerve of arm and forearm) • DD-proximal posterior cord lesion –normal deltoid( axillary N) and latissmus dorsi (thoracodorsal N)
  19. 19. POSTERIOR INTEROSSEOUS NEUROPATHY • Entrapment in arcade of Frohse • Other causes-ganglion, cyst ,tumours • Similar to spiral groove lesion clinically • Wrist and finger drop with sparing of extension • Differentiating features from spiral groove lesion – Sparing of brachioradialis,ECRL and brevis ,triceps – Able to extend wrist weakly with radial tilt – No sensory findings However pain in forearm-deep sensory fibres
  20. 20. SUPERFICIAL RADIAL SENSORY NEUROPATHY • Superficial location • Cheiralgia paraesthetica • Tight fitting watches,bandss,bracelets,hand cuffs • No weakness
  21. 21. RADIAL TUNNEL SYNDROME • Isolated pain and tenderness in extensor forearm • thought to result form compression of PIN • No neurologic signs and normal Edx • Increased painn with manuevers that contract ECR (resisted extension of middle finger) or supinator( resisted supination)
  22. 22. Differential diagnosis of wrist drop • PIN • Radial nerve in spiral groove • Radial nerve in axilla • Posterior cord • C7 root • CNS
  23. 23. • C7 –extend wrists and fingers with sparing of non radial C7 muscles • If severe C7 radiculopathy-weakness of pronator teres and FCR-weakness of arm pronation and flexion • Central lesions- increased tone,DTR ,slowness of movement and associated findings and altered sensation beyond radial nerve distribution
  24. 24. DD
  25. 25. ELECTROPHYSIOLOGIC EVALUATION- NCS
  26. 26. ELECTROPHYSIOLOGIC EVALUATION- NCS RADIAL MOTOR STUDY • EIP muscle –G1- 2 finger breadth proximal to ulnar styloid • G2 – over ulnar styloid • Stimulate –in groove between biceps and brachioradialis,below and above • CMAP 2-5 mV • Compare with contralateral side
  27. 27. RADIAL MOTOR STUDY
  28. 28. Recommended NCS protocol for Radial neuropathy • Radial motor study-EI –stimulating forearm, elbow,below and above spiral groove-bilateral studies • Ulnar motor study –Abductor digiti minimi at wrist,below and above groove in flexed elbow position • Median Motor study-Abductor pollicis brevis at wrist and antecubital fossa • Median and ulnar F responses • Superficial radial sensory nerve -extensor tendons to thumb,stimulating forearm • Ulnar sensory study-recording digit 5 –stimulating wrist • Median sensory-recording digit 2 or 3 –stimulating wrist
  29. 29. Results • PIN(axonal)- normal superficial radial SNAP, low amplitude distal radial CMAP • PIN(demyelinating)- normal superficial radial SNAP, normal amplitude distal radial CMAP with motor conduction block between forearm and elbow • PIN(mixed axonal & demyelinating)- normal superficial radial SNAP, low amplitude distal radial CMAP with motor conduction block between forearm and elbow • Radial neuropathy at spiral groove (axonal lesion ) - reduced superficial radial SNAP, low amplitude distal radial CMAP ,No motor conduction block across spiral groove • Radial neuropathy at spiral groove (demyelinating)- Normal superficial radial SNAP, Normal amplitude distal radial CMAP with motor conduction block across spiral groove • Radial neuropathy at spiral groove (mixed axonal & demyelinating lesion )- reduced superficial radial SNAP, Low amplitude distal radial CMAP with motor conduction block across spiral groove • Radial neuropathy at axilla (axonal lesion )- reduced superficial radial SNAP, low amplitude distal radial CMAP . • Radial neuropathy at axilla (demyelinating lesion )- Normal superficial radial SNAP, Normal amplitude distal radial CMAP with normal motor study to above spiral groove • Superficial radial sensory neuropathy- Reduced superficial radial SNAP, normal radial motor study
  30. 30. Technical considerations • Placing G1 over EI-initial positive deflection- volume conducted potentials from nearby radial innervated muscles(EPB and EPL) • Difficult accurate surface measurements- circutaneous course • These 2 together cause factitiously fast CV • But we look for conduction block and axonal loss • PIN are pure axonal- so no conduction block- so distal CMAP decreased proportional to the axonal loss
  31. 31. Demyelinating lesion in spiral groove
  32. 32. RADIAL SENSORY STUDY • Superficial sensory radial is easy to stimulate & record • G1 – extensor tendons of thumb • G2 – 3 to 4 cm distally • Stimulation – 10 cm proximally over radius • Always compare the other side • If demyelinating – normal SNAP
  33. 33. RADIAL SENSORY STUDY
  34. 34. Radial SNAP
  35. 35. • 3 situations with normal SNAP( when clinically sensory signs +) – Hyper acute axonal loss – Lesion proximal to dorsal root ganglion – Lesions caused by proximal demyelination(radial groove and axilla) • In PIN – usually normal SNAP
  36. 36. Wrist drop with normal SNAP-DD • PIN • Lesions caused by proximal demyelination(radial groove and axilla) • C7 radiculopathy • CNS lesion • Hypercute axonal loss injury < 4 days
  37. 37. ELECTROPHYSIOLOGIC EVALUATION- EMG
  38. 38. ELECTROPHYSIOLOGIC EVALUATION- EMG • To distinguish • PIN • Lesion inradial groove and axilla • C7 radiculopathy • CNS lesion- MUAP configuration and recruitment will be normal in weak muscles, but decreased activation of normal configuration MUAPs will be seen
  39. 39. EMG PROTOCOL • Atleast 2 PIN muscles( EI,ECU,EDC) • atleast 1 radial innervated muscle proximal to bifurction of main radial nerve near elbow but distal to spiral groove( Brachioradialis,ECRL) • atleast 1 radial innervated muscle proximal to spiral groove( triceps,anconeus) • At least one non radial posterior cord innervated muscle(deltoid & Latissmus dorsi) • Atleast 2 non radial C 7 innervated muscle ( PT, Flexor digitorum,superficialis,cervical paraspinals)
  40. 40. • In pure demyelinating lesions with conduction block only abnormality will be decreased recruitment of MUAPs in weak muscles
  41. 41. THANK YOU

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