ANATOMY OF RADIAL NERVE AND WRIST DROP

1. ANATOMY OF RADIAL
NERVE AND WRIST DROP
DR. BIPUL BORTHAKUR
PROFESSOR,
DEPARTMENT OF ORTHOPAEDICS
SILCHAR MEDICAL COLLEGE AND HOSPITAL

2. ANATOMY OF RADIAL NERVE
o The radial nerve isacontinuation of posterior cord of
brachial plexus.
o It isthe largestnerve of the brachial plexus.
o It suppliesthe posterior(extensor)
compartment of upperlimb.
o It carriesfibres from all the roots(C5,C6,C7, C8,andTl)of
brachialplexus .

3. 1

4. COURSE IN AXILLA
• The radial nerveliesposterior to the third partof the
axillaryartery andanteriorto the musclesforming the
posterior wall of the axilla.
• Hereit givesoff the following three branches:
1. Posterior cutaneousnerveofarm
2. Nerveto the long headoftriceps.
3. Nerveto the medial headoftriceps

5. COURSEINTHEARM
• Radialnerveentersthe arm
at the lower border of
the teresmajor.
• It passesbetweenthe long
and medialheadof tricepsto
enter the lower triangular
space,through whichit
reachesthe spiralgroove
alongwith profundabrachii
artery.

7. BRANCHES IN SPIRAL GROOVE
•Five branches:-
1. Lowerlateral cutaneousnerveof thearm.
2. Posteriorcutaneousnerveof theforearm.
3. Nerveto lateral headof triceps.
4. Nerveto medialheadoftriceps.
5. Nerveto anconeus(itrunsthrough the substanceof medialheadoftricepsto reachtheanconeus).

8. • At the lower 3rd of the
humerus, it piercesthe
lateral intermuscular
septumto enter anterior
part of the arm.
• It lies between the
brachialismedially and
brachioradialis and extensor
carpiradialislongus laterally.

9. COURSE IN FOREARM
• Toenter the forearm, the
radial nerve moves
anteriorly over the lateral
epicondyle of the
humerus.
• In the cubital fossa, it
terminate into two
branches:
1. Surperficial branch
(sensory).
2. Deep branch (motor) also
called as posterior
interosseous nerve

11. COURSE OF SUPERFICIAL RADIAL NERVE
It descends deep to brachioradialis ,emerges proximal
to radial styloid process and passes over the roof of
anatomical snuff-box.
It supplies skin over the lateral part of the dorsum of
hand and dorsal surfaces of lateral 3⅟₂ digits
(excluding the nail beds).

13. RADIAL NERVE PALSY
Clinical findings
The patient loses the ability to extend the wrist, fingers and thumb movements that are
essential for function grasp.
In addition patient loses the grip strength because he cannot stabilize the wrist during
power grip.
A high radial nerve palsy is defined as an injury proximal to the elbow. Wrist, fingers(MCP
joint) and thumb extension and abduction are lost and results in WRIST DROP.

14. RADIAL NERVE PALSY
Clinical findings
Low radial nerve palsy is defined as injury to the PIN, occurs distally to the elbow. Wrist
extension is preserved because the more proximally innervated ECRL remains intact.
If the PIN is injured proximally ECU function may be lost resulting in radial deviation and
wrist extension.
If the injury to the PIN is more distal ECU function is preserved and wrist extension remains
balanced.

15. ETIOLOGY
Humeral fractures – during
fracture(Holstein-Lewis) or during surgery
Iatrogenic – upper limb surgery
Direct trauma
Prolonged application of tourniquet
Crutch palsy
Intramuscular injections
Compression neuropathies-
Saturday night paralysis

16. WRIST DROP

17. Lesionsof the radialnerve
Lesions Motor deficits Sensory loss
Lesionat theaxilla Tricepsweakness Lateral dorsum of the handand
injured by the pressure
of the upper end of
crutch (crutch palsy),
by adislocation atthe
shoulder joint,
Brachioradialis weakness
Extensor weaknessof the
wrist - "wristdrop”
wrist
Dorsumof the thumb
Proximal dorsum of fingers
2 and 3
Byafracture of
the proximal humerus.
Lesionat thespiral Tricepsis spared! Lateral dorsum of the handand
wrist
Dorsumof the thumb
Proximal dorsum of fingers
2 and 3
groove of humerus: Brachioradialis weakness
Midshaft fracture of
humerus.
Wrongly placed
Extensor weaknessof the
wrist - "wrist drop”
intramuscular injection.
Saturday night paralysis.
Lesionat the radial
tunnel
(humeroradialjoint)
Extensor weaknessof the
wrist - "wrist drop" -maybe
mild
Lateral dorsum of the handand
wrist
Dorsumof the thumb
Proximal dorsum of fingers 2 &3.

18. TREATMENT OF RADIAL PALSY
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
 Wrist drop can be treated successfully by splints

19. 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
weak wrist extensor
 It continues to act as a substitute in case nerve regeneration
is poor or absent

20. INDICATIONS FOR SURGERY
 In a sharp injury exploration is indicated for diagnostic,
therapeutic and prognostic purposes
 In avulsion , blasting injures –to identification of the
nerve injury and making the ends of the nerve with
sutures for later repair.
 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.

21. OPERATIVE MANAGEMENT
Nerve repair
Neurolysis
Tendon transfer

22. TENDON TRANSFER FOR
RADIAL NERVE PALSY
There are three main goals:
Restoration of finger(MCP joint) extension
Restoration of thumb extension
Restoration of wrist extension
Three main patterns of tendon transfer
Jones transfer
Brand’s transfer
Boyes transfer

23. TENDON TRANSFER FOR
RADIAL NERVE PALSY
Restoration of wrist extension
Most accepted method is PT to ECRB transfer.
If recovery of the radial nerve is not expected, the transfer should be done in end-to-end
fashion.
If the radial nerve has been repaired and ECRB re-innervation is expected in the future, the
transfer should be done in a end-to-side fashion.

25. TENDON TRANSFER FOR
RADIAL NERVE PALSY
Restoration of thumb extension
The Palmaris longus or ring finger FDS are most often used.
When the ring FDS is used, it can be split and inserted into the both EPL and the EIP,
allowing concomitant thumb and index finger extension.
When the PL is used as a motor, the EPL is usually rerouted volarly to meet the PL in a direct
line of pull, which results in abduction of the thumb as well as IPJ extension.

27. TENDON TRANSFER FOR
RADIAL NERVE PALSY
Restoration of finger MCP joint extension
Can be done transferring the FCR, FCU or FDS tendon.
Jones transfer: In 1900s Jones popularized the use of FCU to restore MCP extension
Jones transfer sacrifices the only remaining ulnar-sided wrist motor which results in radial
deviation of the wrist along with the loss of ulnar deviation with wrist flexion which is an
important wrist motion essential for activities like hammering and throwing.

29. POST-OPERATIVE CARE
AND REHABILITATION
Regardless of the procedure performed the patient should be placed in an above elbow splint or
cast.
The elbow should be flexed at 90 degree with forearm pronated and wrist extended at 30
degree.
This takes tension off the PT to ECRB transfer.
The thumb should be abducted and extended and MCP joints of the fingers extended to take
tension off the transfers to the EDC and the EIP.
The IP joints of the fingers should be left free.

30. POST-OPERATIVE CARE
AND REHABILITATION
The post-operative splint can be changed at one to two weeks for wound check and to refit the
splint.
At 4 weeks post-operatively a thermoplastic splint should be fabricated.
During the first 4 weeks of the surgery it is important to maintain the ROM of the shoulder and
the IP joints of the fingers.
At 4 weeks mobilization begins and exercises will focus on mobilization of single joints at a time
while keeping tension off the transfer.
Mobilization begins with active ROM and advance to gentle passive ROM.

31. THANK YOU