2. âą Largest branch of the brachial plexus
âą Arises from the posterior cord of the brachial plexus (C5âT1)
âą Mixed nerve
Radial Nerve
Anatomy
3. Course of Radial Nerve (RN) in the arm
In the axilla, RN lies
anterior to
subscapularis, teres
major and LD
âą Sensory supply:
Posterior cutaneous
nerve of arm
RN leaves the axilla
via the triangular
space
âą 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
âą Motor: medial and lateral
heads of triceps,
Anconeus
âą 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
âą Motor supply: Brachialis
(lateral part), BR, ECRL
Anterior to lateral
epicondyle, RN divides
into its terminal branches
âą Terminal branches:
Posterior Interosseous Nerve
(PIN) and Dorsal or
Superficial radial sensory
nerve
Here it lies b/w brachialis and BR
5. Deep terminal branch â
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 muscles
Finally, PIN ends by
supplying carpal joint
sensation
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 â 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. 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,
middle finger proximal to the
distal interphalangeal joint.
Cutaneous innervation from radial
nerve
8. - crutch palsy
- aneursysm of axillary
vessels
Total palsy
Aetiology and clinical features
Very high radial nerve
palsy
Clinical features
9. - # shaft of humerus
-prolonged application of
tourniquet
-pressure on arm as in
Saturday night paralysis
-injections
-from excessive callus
formation of old fracture
impinging on the nerve
- Elbow extension spared
- Lost: Wrist, thumb and
finger extension; sensation
over 1st web space
High radial nerve palsy Clinical features
10. -Dislocation of elbow
-#neck of radius
-Enlarged bursae
-Rheumatoid synovitis of
elbow
-During operation for
excision of radius head
- Elbow extension spared
with weak wrist extension
and radial deviation
- Lost â thumb , finger
extension: sensory over
dorsum of 1st web space
Low radial nerve palsy Clinical features
12. Mechanism of injury (e.g. sharp
penetrating vs. blunt trauma)
Timing of injury
Loss of motor and sensory function
Presence of pain
Interval recovery of function in patients
presenting late
History
13. Assessment of motor function
Assessment of sensory function
Assessment of involved joints
Physical
Examinatio
n
Individual muscles innervated by
the nerve are tested to determine
what is functioning and what is not:
âȘHelps to determine the level of
injury
âȘGuides future surgical planning
âȘElicitation of Tinelâs sign
âȘSpecific sensory testing
Each joint is taken through its
passive range of motion to assess
for suppleness â presence of fixed
joint contractures in delayed
presentations is associated with
poor treatment outcomes
14. Specific sensory tests
Test Perception Main receptor Comments
Static 2 point
discrimination (2PD)
Tactile Merkel cell âȘEvaluates sensory
receptor innervation
density
âȘNormal distance:
6mm
Moving 2PD Tactile Meissner corpuscle âȘNormal distance:
3mm
Tuning fork (250 Hz) Vibration Pacinian corpuscle
Tuning fork (30 Hz) Vibration Meissner
Semmes-Weinstein
monofilament test
Pressure Merkel
Ten test (moving light
touch)
Pressure Merkel âȘReliability
comparable to
monofilament test
Cold-heat test Temperature Free nerve endingsâąChanges in Vibration and Pressure thresholds are seen in early nerve compression but are unreliable for
evaluating nerve lacerations
âąChanges in sensory receptor innervation density (2PD) are seen in chronic nerve compression but are
reliable for evaluating nerve lacerations
15. Commonly used EDT
-Electromyography (EMG)
-Nerve conduction studies (NCS)
1. Documentation of injury
2. Location of insult
3. Severity of injury
4. Recovery pattern
5. Prognosis
6. Objective data for impairment documentation
7. Pathology
8. Selection of optimal muscles for tendon transfer procedure
Electrodiagnostic testing
16. Limitations of EDT:
âȘEvaluates only large myelinated fibres â smaller axons conveying
pain and temperature are not assessed
âȘChanges in unmyelinated nerve fibres, which are the first to be
affected in nerve compressions, are not evaluated
âȘPerforming the test before 3-6 weeks post injury can give
inaccurate results
âȘVery proximal or distal nerve injuries are difficult to assess
âȘUnreliable assessment of multi-level injuries
âȘExaminer dependant
17. 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
âą represents the size of the
response
âą proportional to the number
of depolarizing axons in
the nerve
Latency
âą the delay in response
following stimulation
Conduction velocity
Sensory nerve action
potential (SNAP)
âą Response obtained when
the recording electrodes is
placed proximally along
the sensory nerve, toward
the spinal cord
Compound motor action
potential (CMAP)
âą Response obtained when
the recording electrodes is
placed distally at the
target muscle
18. Electromyography (EMG)
âą Activity observed when a needle
electrode is inserted into the muscle
Insertional activity
âą Seen when the muscle is at rest
âą Absent in normal musclesâȘFibrillation potentials
âȘFasciculations
âą Generated by the muscle during a
voluntary contraction
âą Evaluates the integrity of neuro-
muscular junction
Motor unit potentials
(MUPs)
19. 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
âȘâLatency
âȘâNerve conduction
velocity
Associated Electrodiagnostic
findings
âȘâSNAP
âȘâCMAP
âȘâInsertional activity
âȘFibrillation potentials and
fasciculations
âȘâGiantâ MUPs
âȘNormalization of NCV
âȘLoss of âgiantâ MUPs
20. ï Non-operative
-full passive range of motion in all
joints of the wrist and hand and
prevention of contractures, including
that of the thumb-index web
- splints
ï wrist drop can be treated successfully
by splints
ï Barkhalter has observed that grip
strength may be increased by 3 to 5
times by simply stabilizing the wrist
with splints
ï Many types of splints have been
described
ï Each patient individual need should
TREATMENT
21. INTERNAL SPLINT
ï Burkhalter proposed early transfer of PT-ECRB to restore
wrist extension as an adjunct to nerve repair.
ï It restores the power grip quickly and effectively since wrist
extension is restored
Advantages are:
ï It works as a substitute during nerve regrowth and largely
eliminates an external splint
ï Subsequently the transfer aids the newly innervated and weak
wrist extensor
ï It continues to act as a substitute in case nerve regeneration is
poor or absent
Greenâs operative hand
22. ï In a sharp injury exploration is indicated for diagnostic,
therapeutic and prognostic purposes
ï In avulsion , blasting injures âto identification of the
nerve injury and making the ends of the nerve with
sutures for later repair.
ï When a nerve deficit follows blunt or closed trauma,
and no clinical or electrical evidence of regeneration
has occurred after an appropriate time, exploration of
the nerve is indicated.
INDICATIONS FOR SURGERY
23. -primary repair gives the best result with respect to
motor,sensory recovery, is indicated in clean sharp nerve
injuries and carried out in first 6-8 hours.
-delayed,primary repair carried out between 7-18days -
primary repair fascicular alignment because of minimal
excision of the nerve ends.
-Secondary repair-preferable only in crushed,avulsed
injuries where patients life is seriously endangered.it is
done at delay of 3-6 wks.
Time of surgery
24. ï Seddon has suggested the
maximum length of time that
may be required for motor
recovery to first manifest
itself can easily be calculated
by measuring the distance
on the x-ray from the fracture
site to the point of
innervation of the
brachioradialis muscle
(approximately 2 cm above
the lateral epicondyle)
Green's Operative Hand
Surgery
Nerve Exploration If No Return After a Longer
Waiting Period
29. ï Tendon transfers
ï Arthodesis
ï Tendon transfers work to correct:
ï instability
ï imbalance
ï lack of co-ordination
ï restore function by redistributing remaining
muscular forces
RECONSTRUCTIVE
PROCEDURES
30. ï A patient with irreparable radial nerve palsy
needs to be provided with
(1) wrist extension.
(2) finger (metacarpophalangeal [MP] joint)
extension.
(3) a combination of thumb extension and
abduction.
Requirements in a Patient with Radial Nerve
Palsy
31. ï 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
TENDON TRANSFER
34. a long arm splint is applied that
ï immobilizes the forearm in 15 to 30degrees of pronation.
ï the wrist in approximately 45 degrees of extension.
ï the MP joints in slight (10 to 15 degrees) flexion.
ï the thumb in maximum extension and abduction.
ï The proximal interphalangeal joints of the fingers are left
free.
The cast is removed 4 weeks postoperatively; removable
short arm splints to hold the wrist, fingers, and thumb in
extension are made, which the patient wears for an
additional 2 weeks, removing them only for exercise.
Postoperative Management
36. Wartenbergâs syndrome
âą Aka: Cheiralgia paresthetica
âą D/t compression of Superficial radial nerve as it
emerges b/w ECRL and BR, 8 cm proximal to
radial styloid
37. isolated pain or paresthesias
over the dorsoradial aspect
of the hand
preceding history of trauma
to the area (i.e., handcuffs,
forearm fracture)
Differentiating Wartenbergâs
syndrome from de
Quervainâs tenosynovitis
A Tinelâs 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
â in pronation, the tendons
of BR and ECRL approximate
and may compress the nerve
âȘIn WS, pain is exacerbated by pronation, while in
DQT pain is elicited with changes in thumb and wrist
position
âȘDQT - normal sensation in the dorso-radial hand
âȘDQT - pain on percussion over the 1st extensor
compartment
Electrodiagnostic testing is of
limited value in Wartenbergâs
syndrome
38. Posterior interosseous nerve (PIN) syndrome
âą D/t compression of PIN in the radial tunnel
âą Most common causes include:
âȘTumors such as lipomas, ganglia
âȘRheumatoid synovitis
âȘSeptic arthritis
âȘVasculitis
39. The radial tunnel is a 5 cm
space bounded by:
âȘDorsally: capsule of the
radiocapitellar joint
âȘVolarly: the BR
âȘLaterally: the ECRL and ECRB
muscles
âȘMedially: the biceps tendon and
brachialis muscles
Within radial tunnel, there are 5
potential sites of compression:
âȘfibrous bands to the
radiocapitellar joint between the
brachialis and BR
âȘthe recurrent radial vessels
(leash of Henry)
âȘthe proximal edge of the ECRB
âȘthe proximal edge of the
Supinator (arcade of Fröhse)
âȘthe distal edge of the Supinator
BR
Supinator
arcade of Fröhse
ECRL
PIN
40. Diagnosis
loss of finger and thumb extension
Weak wrist extension with radial deviation
(since ECRL innervation is intact)
Intact passive tenodesis effect
(rules out extensor tendon rupture)
EMG testing is helpful to confirm the
diagnosis and monitor motor recovery
41. Radial Tunnel syndrome
âą Similar to PIN syndrome, it is also d/t
compression of PIN in the radial tunnel
âą Not considered a true compression neuropathy
by some
42. 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
â Pain on combined
elbow extension,
forearm pronation,
and wrist flexion
Many types of splints have been designed for patients with radial nerve palsy, most of which offer some type of extension assist.A, In one of the less cumbersome designs, passive MP extension is provided by simple elastic webbing beneath the proximal phalanges.B, Active flexion of the PIP joints is not impeded
Transfer of pronator teres (PT) to extensor carpi radialis brevis (ECRB), transfer of flexor carpi radialis (FCR) to extensor digitorum communis (EDC), and palmaris longus (PL) to rerouted extensor pollicis longus (EPL). A and B, Volar and dorsal incisions used in combination of transfers. Note short transverse incisions over thumb metacarpal joint dorsally and wrist volarly used in rerouting EPL. C, Transfer of PT into more centralized ECRB. PT insertion is harvested with 2- to 3-cm periosteal extension strip. D, FCR transfer to EDC. FCR motor tendon attachment at 45-degree angle into recipient tendon. E and F, Transfer of PL to rerouted EPL. By rerouting EPL out of its third extensor compartment, combination of thumb abduction and extension can be achieved.