Radial nerve injuries

1. RADIAL NERVE
INJURY AND
MANAGEMENT
SUSHANT S. SONARKAR

2. ANATOMY:
 Posterior cord,(C5-6,7,8,T1),
 Largest branch,
 Predominantly motor,

3. Course of Radial Nerve (RN) in the
arm
In the axilla, RN lies
anterior to
subscapularis, teres
major and LD
• Sensory supply:
Posterior cutaneous
nerve of arm
RN leaves the axilla
via the triangular
space
• Motor supply:
long head of
Triceps
It then comes to lie
along spiral groove
on posterior aspect of
humeral shaft along
with arteria profunda
brachii
• Motor: medial and lateral
heads of triceps,
Anconeus
• Sensory: posterior
cutaneous nerve of
forearm, lower lateral
cutaneous nerve of arm

4. RN then leaves the spiral
groove by piercing the lateral
intermuscular septum to enter
the anterior compartment of
the arm, 10-12 cm above the
lateral epicondyle
• Motor supply: Brachialis
(lateral part), BR, ECRL
Anterior to lateral
epicondyle, RN divides into its
terminal branches
• Terminal branches:
Posterior
Interosseous Nerve
(PIN) and Dorsal or
Superficial radial
sensory nerve
Here it lies b/w brachialis
and BR

5. Radial nerve (C5, 6, 7 , 8,
T1) exiting axilla via the
triangular space
Brachialis (lateral part)
Anconeus
Triceps brachii
Posterior cutaneous nerve
of forearm
Posterior cutaneous nerve
of arm
Lower lateral cutaneous
nerve of arm
Radial nerve in the spiral
groove (posterior aspect
of humeral shaft)
Brachioradialis (BR)
ECRL (last branch of
radial nerve proper)
Lateral intermuscular
septum

6. BR
ECRL
Dorsal Radial Sensory
Nerve
Dorsal digital nerves
Radial styloid
8 cm
Dorsal radial nerve
courses through the
forearm immediately
deep to the BR
It emerges b/w
tendons of BR and
ECRL ≈ 8 cm
proximal to radial
styloid, to become
subcutaneous
It crosses the
anatomical snuffbox
b/w EPB and EPL,
dividing into multiple
branches to supply
sensation to hand
Course of Radial Nerve (RN) in the
forearm

7. Deep terminal branch →
Posterior interosseous
nerve (PIN)
Supinator
EIP
EDC and EDM
ECU
ECRB
Superficial terminal branch
Radial Nerve Proper
EPL
EPB
APL
PIN reaches the back of
forearm by passing
around the lateral aspect
of the radius b/w the
superficial and deep
heads of the Supinator
to supply all extensor
compartment.
Finally, PIN ends by
supplying carpal joint
sensation

8. Lower lateral cutaneous
nerve of arm
Posterior cutaneous
nerve of arm
Posterior cutaneous
nerve of forearm
Dorsal radial sensory nerve
Gives sensibility to the dorsum of
the hand over the radial two-thirds,
the dorsum of the thumb, and the
index, long, and half of the ring
finger proximal to the distal
interphalangeal joint.
Cutaneous innervation from radial
nerve

9. Inspection
Attitude and deformity : note any typical attitude
of the wrist drop
Wasting of the muscles in longstanding
paralysis
Skin becomes dry , glossy and smooth with
disapperance of cutaneous folds and
subcutaneous fat
Scar or wound
Palpation of the nerve
If there is tenderness on pressure along the
course of the nerve- indicates inflammation of
the nerve
In the course of the nerve where complete
divison of nerve is expected feeling of neuroma
and glioma almost confirm the diagnosis

12. ETIOLOGY:
 In the Axilla,
 In the shoulder,
 In the Radial groove,
 Between spiral groove and the lateral epicondyle,
 At the elbow,
 In the forearm,
 Other causes,

13. TYPES OF INJURY:
 Primary injury,
 Secondary Injury,

14. Clinical
Features

15. Functional motor deficit
Inability to extend the wrist (in
case of injury at level of PIN,
wrist extension is weak with
radial deviation since ECRL
innervation is intact)
Inability to extend the fingers at
the MCP joints
Inability to extend and radially
abduct the thumb
Weakness of grip strength d/t
loss of mechanical advantage
that wrist extension provides
for grasp and power grip

16. Area of sensory loss in
radial nerve injury in the
axilla
Unlike the median and ulnar
nerves, sensory loss
following radial nerve injury is
not functionally disabling
unless the patient develops a
painful neuroma
Sensory Loss
Autonomous sensory zone
for radial nerve → dorsum of
1st webspace
The Lateral cutaneous nerve
of forearm has a significant
overlap pattern with the
Superficial radial sensory
nerve

17. CLINICAL FEATURES:
 VERY HIGH RADIAL NERVE PALSY: ( in axilla)
 Motor paralysis:
1. Triceps, anconeus,
2. Brachioradialis,
3. Supinator,
4. Long Extensors of wrist.
 Sensory Paralysis:
1. Loss of skin sensations in posterior surface of lower arm and back of
forearm,
2. Lateral three and one half fingers(dorsum)

18. HIGH RADIAL NERVE PALSY:
(Radial Groove)
 Motor paralysis:
1. Brachioradialis,
2. Supinator,
3. Long extensors of wrist.
 Sensory paralysis:
Back of hand, radial side of thumb, and adjoining part of thenar
eminence
The medial side of thumb , index , middle and lateral part of
ring fingers.

19. LOW RADIAL NERVE
PALSY:
 Motor paralysis:
1. EDC, EDM,EDI,ECU
2. APL,EPL,EPLB
 Sensory loss:
1. No sensory loss

20. TEST FOR RADIAL NERVE
INJURY:
 Test for brachioradialis,
 Test for extensors of wrist,
 Test for extensor digitorum,
 Hitch Hiker sign,

21. Diagnostic Tests:
 Modality tests,
 Functional tests,
 Objective test,
1. Sweat test,
2. Skin resistance test,
3. Wrinkle test,
4. Tinel’s sign,
5. Positive axon reflex test.

22. ELECTROPHYSIOLOGICAL
STUDY:
 Electromyography,
 Motor nerve conduction studies,
 Strength duration Curve,

23. Electromyography (EMG)
Nerve conduction studies
(NCS)
Electrodiagnostic
testing
Helpful in arriving at a
diagnosis in presence of
atypical presentations or
equivocal clinical findings
Limitations of EDT:
▪Evaluates only large myelinated
fibres → smaller axons conveying
pain and temperature are not
assessed
▪Changes in unmyelinated nerve
fibres, which are the first to be
affected in nerve compressions, are
not evaluated
▪Performing the test before 3-6
weeks post injury can give inaccurate
results
▪Very proximal or distal nerve injuries
are difficult to assess
▪Unreliable assessment of multi-level
injuries
▪Examiner dependant

24. Nerve conduction studies (NCS)
2 electrodes are placed along the course of the
nerve. The first electrode stimulates the nerve
to fire, and the second electrode records the
generated action potential
Amplitude
• represents the size of the
response
• proportional to the number
of depolarizing axons in
the nerve
Latency
• the delay in response
following stimulation
Conduction velocity
Sensory nerve action
potential (SNAP)
• Response obtained when
the recording electrodes is
placed proximally along
the sensory nerve, toward
the spinal cord
Compound motor action
potential (CMAP)
• Response obtained when
the recording electrodes is
placed distally at the
target muscle

25. Electromyography (EMG)
• Activity observed when a needle
electrode is inserted into the muscle
Insertional activity
• Seen when the muscle is at rest
• Absent in normal muscles
▪Fibrillation potentials
▪Fasciculations
• Generated by the muscle during a
voluntary contraction
• Evaluates the integrity of neuro-
muscular junction
Motor unit potentials
(MUPs)

26. Sequence of events in nerve
compression
Focal demyelination
Axonal damage at the
compression site
Further axonal loss
Axonal sprouting producing
collateral re-innervation
Remyelination following
decompression
▪↑Latency
▪↓Nerve conduction
velocity
Associated Electrodiagnostic
findings
▪↓SNAP
▪↓CMAP
▪↑Insertional activity
▪Fibrillation potentials and
fasciculations
▪’Giant’ MUPs
▪Normalization of NCV
▪Loss of ‘giant’ MUPs

27. Wartenberg’s syndrome
• Aka: Cheiralgia paresthetica
• D/t compression of Superficial radial nerve as it
emerges b/w ECRL and BR, 8 cm proximal to
radial styloid

28. isolated pain or paresthesias
over the dorsoradial aspect
of the hand
preceding history of trauma
to the area (i.e., handcuffs,
forearm fracture)
Differentiating Wartenberg’s
syndrome from de
Quervain’s tenosynovitis
A Tinel’s sign over the
superficial sensory radial
nerve is the most common
exam finding
Clinical features
presence of motor weakness suggests a
more proximal site of compression
Also seen in patients who
use forearms in pronated
position for extended periods
→ in pronation, the tendons
of BR and ECRL approximate
and may compress the nerve
▪In WS, pain is exacerbated by pronation, while in
DQT pain is elicited with changes in thumb and wrist
position
▪DQT - normal sensation in the dorso-radial hand
▪DQT - pain on percussion over the 1st extensor
compartment
Electrodiagnostic testing is of
limited value in Wartenberg’s
syndrome

29. Posterior interosseous nerve (PIN) syndrome
• D/t compression of PIN in the radial tunnel
• Most common causes include:
▪Tumors such as lipomas, ganglia
▪Rheumatoid synovitis
▪Septic arthritis
▪Vasculitis

30. The radial tunnel is a 5 cm
space bounded by:
▪Dorsally: capsule of the
radiocapitellar joint
▪Volarly: the BR
▪Laterally: the ECRL and ECRB
muscles
▪Medially: the biceps tendon and
brachialis muscles
Within radial tunnel, there are 5
potential sites of compression:
▪fibrous bands to the
radiocapitellar joint between the
brachialis and BR
▪the recurrent radial vessels
(leash of Henry)
▪the proximal edge of the ECRB
▪the proximal edge of the
Supinator (arcade of Fröhse)
▪the distal edge of the Supinator
BR
Supinator
arcade of Fröhse
ECRL
PIN

31. Radial Tunnel syndrome
• Similar to PIN syndrome, it is also d/t
compression of PIN in the radial tunnel
• Not considered a true compression neuropathy.

32. Radial Tunnel Syndrome is a clinical diagnosis
Radial Tunnel
Syndrome
Tenderness over
radial tunnel
(lateral proximal
forearm, 3-4 cm distal
to lateral epicondyle
over the mobile wad)
Pain at ECRB origin
with resistance of
middle finger
extension
Pain with resisted
forearm supination
↑ Pain on combined
elbow extension,
forearm pronation,
and wrist flexion

33. Proximal Radial nerve compression
• Compression of the radial nerve proximal to the elbow is
uncommon.
• Causes:
▪Fibrous arch from the lateral head of triceps
▪After strenuous muscular activity
▪Bony exostosis of humerus
▪Injury in spiral groove:
▫# shaft humerus
▫‘Saturday night palsy’ (neuropraxia)
▫Post injection palsy (chemical neurotmesis)
• Patients present with variable degrees of radial nerve
dysfunction

34. Management:
 In nerve root avulsion injuries: non operative, early
neurotization,
 Open injuries,
 Closed injuries,

35. SURGICAL TECHNIQUES
 Techniques of neurorrhaphy :
-partial neurorrhaphy
-epineural neurorrhaphy
-perineural neurorrhaphy
-epiperineural neurorrhaphy
-interfasicular nerve grafting

36. MANAGEMENT
 Nerve grafting:
Types of graft
-Trunk graft
-Cable graft
-Pedicle nerve graft
-Inter fascicular nerve graft
-Pre vascularized nerve graft
Source of graft
-Sural nerve is probably the best source of graft in majority of cases
-Medial and lateral cutaneous nerve at the wrist is an ideal donor graft for
fascicular nerve after for digital nerve
-Superifical radial nerve is an excellent source of graft generally used in case of radial
nerve injuries
-Dorsal branch of ulnar nerve can also be used as a graft.

37. RECONSTRUCTIVE PROCEDURES
 Tendon transfers
 Arthodesis
 Tendon transfers work to correct:
 instability
 imbalance
 lack of co-ordination
 restore function by redistributing remaining muscular
forces

38. TENDON TRANSFER
 Robert jones described 2 sets of tendon transfers
1916: PT - ECRL and ECRB
FCU - EDC III,IV,V
FCR - EDCII,EIP and EPL
1921: PT - ECRL and ECRB
FCU - EDC III,IV,V
FCR - EDCII,EIP , EPL,APL ,EPB
Current standard tendon transfer protocol BRANDT
PT - ECRB
FCR- EDC
PL - EPL

40. INTERNAL SPLINT
 Burkhalter proposed early transfer of PT-ECRB to restore
wrist extension as an adjunct to nerve repair.
 It restores the power grip quickly and effectively since
wrist extension is restored
Advantages are:
 It works as a substitute during nerve regrowth and largely
eliminates an external splint
 Subsequently the transfer aids the newly innervated and
week wrist extensor
 It continues to act as a substitute in case nerve
regeneration is poor or absent

41. TENDON TRANSFER
 BOYE’S tendon transfer
PT -ECRL and ECRB
FCR - EPB and APL
FDS middle –EDC
FDS ring - EPL and EI
POST OP CARE:
immobilization for 6 weeks
usually maintained for 4 weeks followed by a spring loaded extension
splint for the wrist and finger.
during the cast immobilization the MCP joints held in 40degee of
reflection wrist should be fully extended with thumb in abduction and
extension
ip joints of fingers in comfortable flexion

42. NON-OPERATIVE TREATMENT
 SPLINTS
 wrist drop can be treated successfully by splints
 Bark halter has observed that grip strength may be increased
by 3 to 5 times by simply stabilizing the wrist with splints
 Many types of splints have been described
 Each patient individual need should be dictate
the type of splinting used
 splints are used for patients who are
debilitated and who reject surgery.
Cock up splint)

43. OPPENHEIMER SPLINT
It is a dynamic splint used for radial
nerve palsy
it consists of one palmar bar over the
prox.phalanx,one distal forearm cuff
dorsally and proimal cuff volarly.
Provides global extension of wrist and
fingers
Limitation of this splint:restriction of
grasp due to palmar bar.
Proximal migration of splint cause friction
blisters around the wrist

44. RECOVERY
 Factors influencing the prognosis for recovery
-age
-level of injury
-delay between the time of injury and repair
-gap between nerve ends
-Condition of the nerve
-type of nerve
-

45.  Level of injury:
 The more proximal the injury, the more incomplete the overall return of
motor and sensory function, especially in the more distal structures.
• Delay between the time of injury and repair
-Delay of neurorrhaphy affects motor recovery more profoundly than
sensory recovery
-satisfactory reinnervation of muscle can occur after denervation upto 12
months.
-irreversible changes develop in the muscles after 24 months
-with respect to sensory recovery ,nerve can be repaired even after 2 yrs
for satisfactory recovery. However results are best if done earlier.

46.  Gap between nerve ends
 The methods for closing the gap are
 nerve mobilization
 nerve transposition,
 positioning of the extremity ,
 nerve grafts,
 bone shortening.
Condition of the nerve: A clear cut sharp nerve injury has got better prognosis
following primary repair than crushed or avulsed nerve injuries which needs
secondary repair
Type of nerves: pure motor ,pure sensory nerves recover better than mixed nerves
because the consequence of mismatching are not so great in pure motor or
sensory nerves.