3. Anatomy of Median Nerve
• Mixed nerve
• Runsin the median plane
of the forearm , so its
called median nerve
• Also calledlabourer’s
nerve.
Anatomy of aperipheral nerve
4. Anatomy of Median Nerve
• The median nerve has
contributions from entire
brachial plexus(C5-T1)
• Formed by Lateral(C5,C6,C7)and
Medial(C8,T1) Roots of lateral and
medial cord of brachial plexus
respectively.
5. • After originating from the
brachial plexus in the axilla, the
median nerve descends down
the arm, initially lateral tothe
brachial artery.
• Halfway down the arm, thenerve
crosses over the brachial artery,
and becomes situated medially.
Anatomy of Median Nerve
6. • No branches in the arm
• In the proximal 3rd – lies between
coracobrachialis anteriorly and long head
of triceps posteriorly
• In the middle 3rd – lies between the biceps
brachi anteriorly and long head of triceps
posteriorly
• In the distal 3rd – lies anteromedial
to brachialis muscle and
posteromedial to biceps brachi.
Anatomy of Median Nerve
Course in the Arm:
7. • In the antecubital fossa, the median nerve lies
deep to the bicipital aponeurosis, medial to
the antecubital vein and brachial artery.
• Gives 4 motor branches to-
• Pronator Teres
• Flexor Carpi Radialis
• Palmaris Longus
• Flexor Dig. Superficialis
Anatomy of Median Nerve
Course in the Elbow:
8. At the level of the junction of the two heads
of the pronator teres, the median nervegives
off the anterior interosseous nerve about 5-8
cmdistal tomedialepicondyle.
It courses down the forearm deep to the
flexor digitorum superficialis and superficial
to the flexor digitorum profundus.
In the distal 1⁄3 of the forearm, the median
nerve emerges from beneath the flexor
digitorum superficialis to lie medial to the
flexor carpi radialis and lateral to the
palmaris longus, before entering the carpal
tunnel.
Anatomy of Median Nerve
Course in the Forearm:
9. Anatomy of Median Nerve
• AIN gives branches to :
• Flexor Digitorum Profundus to Index and
Middle Fingers
• Flexor Pollicis Longus
• Pronator Quadratus
• The median nerve also gives a palmar
cutaneous branch, 4 to 5 cm proximal to the
wrist that provides sensation to thenar skin of
the palm.
10. • Within the carpal tunnel: the median nerve
lies immediately palmar and radial to flexor
digitorum tendons and dorsal to transverse
carpal ligaments.
• It gives Recurrent motor branch from the radial
surface – supplies
• Flexor Pollicis Brevis(Superficial Head)
• Abductor Pollicis Brevis
• Oppenens Pollicis
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Anatomy of Median Nerve
Course in the Wrist and Hand:
11. • After exiting carpal tunnel, it splits into two
terminalbranches-theradialandulnardivision
• Radial Division- Common Digital nerve to the
thumb and ProperdigitalNervetoRadialside
ofIndexFinger.
• Ulnar Division- Common digital nerve to
index/middlefingerandmiddle/ringfinger
• The digital nerves also supply 1st
and 2nd Lumbricals
Anatomy of Median Nerve
12. Motor Supplies
superficial volar forearmgroup
• Pronator teres
• Flexor carpiradialis
•Palmaris longus
•Flexor digitorum superficialis
• Deep group
•Flexor digitorum profundus (lateral)
• Flexor pollicis longus
• Pronator quadratus
• Hand
• 1st and 2ndlumbricals
• Opponens pollicis
• Abductor pollicis brevis
• Flexor pollicis brevis
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Anatomy of Median Nerve
13. Sensory innervations
The median nerve is
responsible for the
cutaneous innervation of part
of the hand. This is achieved
via two branches:
Palmar cutaneous
branch
Palmar digital
cutaneous branch
16. LOW MEDIAN NERVE LESION
Causes:
I. Cutsin front of the wrist
II. Carpaldislocation
• Injury Distal to the innervation of forearm
muscles-i.e proximal to forearm
17. Sparing of the forearm muscles
Muscles of the hand paralysed
Anaesthesia over the median nerve
distribution in thehand
Thenar eminence is wasted and thumb
abduction and oppositionare weak
Sensation lost over the radial three and half
digits and trophic changesmay seen
LOW MEDIAN NERVE LESION
18. HIGH MEDIANNERVELESION
AXILLA
Crutch compression
Anterior shoulder dislocation
UPPER ARM- Stab
wounds
Ligament of struthers :
ELBOW
Supracondylar Humerus #
Fracture medial epicondyle
Elbow dislocation
• Injury Proximal to the innervation of forearm
muscles-i.e proximal to forearm
19. HIGH MEDIAN NERVE LESION
Wasting of musclesof forearm
Wasting of thenareminence
Weaknessof thumb abduction and opposition
Lossof abductor pollicis brevis +flexor pollicis brevis
Thehand is held with ulnar fingers flexed and index
finger straight (pointing sign) Lossof FDP
,FDS,FPL
Lost sensationat radial three and half digits
Weak Oksign
Ape handdeformity
21. Evaluation of Median Nerve Palsy
History
• Pain , Numbness or Weakness
• History of trauma
• Duration of symptoms
• Acute or chronic
• Associated injuries
43. ELECTROPHYSIOLOGICAL STUDY
potential (CMAP)
Electromyography
Todetermine completenessof anerve injury
Technique:
I. Very small needleis inserted into various muscle
II. Then,the signal is magnified by high gain amplifier
III. Finally, the reading are monitored via oscilloscopeand
recorded on the magnetic tape or paper recording
IV. Should performed 3-7daysafter peripheral nerve
Injury
V. It may showlow amplitude evoked compound muscle
44. Nerve Conduction Test
–First calculate thresholdby
stimulating on soundside
Measure Median motor and
sensory latencies andconduction
velocities across thewrist
Sensorylatency of greater than
3.5millisecondor amotor latency
of greater than 4.5 millisecond is
considered an abnormalfinding
Distal compound muscleaction
potential (CMAP)and sensory
nerve action potential (SNAP)
amplitudes may bedecreased
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45. PRINCIPLES OF SURGICAL
MANAGEMENT
1. Direct Injury: Nerverepair-
2. Long standingcases: Tendontransfers
Nervetransfers Nervegraft
3. Compressionneuropathies: Decompression
46. GENERAL INDICATIONS OF
SURGERY
In sharp injury- exploration for diagnostic as well as
therapeutic purpose .Neurorrhaphy can be done at time
of exploration or delayed
In avulsion or blast injury –to identify and suture
of nerve endsfor delayed repair
When anerve deficit follows blunt or closed trauma and
no clinical or electrical evedence of regeneration has
occurred after an appropriate time
47. Time of surgery
Primary repair within 6-8 hours gives best
results
Delayedprimary repair –between 7-18days
Secondary repair - 3to 6 weeks later preferable
in crushed ,avulsed , contaminated wounds
where patients life is seriously endangerd
48. SURGICAL TECHNIQUES
Coaptation
Approximating the cut ends of nerve in such a way
that motor fasiculi meets another motor fasiculi and
sensory tosensory
Conventionally done by 8-0 to 10-0 nylon
suture
Sutureless methods includes fibrin clots,
adhesive tapes ,collagentubulization
49. Neurorrhaphy
Neurorrhaphy is end to end suturing of nerve
Types
Partial Neurorrhaphy
EpineuralNeurorrhaphy
Perineural (fascicular)Neurorrhaphy
Epiperineural Neurorrhaphy
Interfascicular nervegrafting
52. Nerve grafting
Agap between cut ends
more than 2.5-4 cm is
indication of nerve graft
Nerves used forgraft
Most commonly suralnerve
Latral antebrachial cutaneousnerve
I n t e r fasc ic ula r nerve grafting
53. Critical Limit of Delay of Suture
Motor recovery in intrinsic muscles of the hand
does not occur if suture is delayed 9 months in
high lesionsor 12months in low ones.
Useful sensory recovery only rarely occurs after 9
months in high lesions or 12months in low ones but
it may occur when suture has been delayed aslong
as2years.
54. Reconstructive procedure
Tendon transfer
Motor recovery may not occur if the axons, regenerating at about 1
mm per day / 2-3 cm per month , don't reach the muscle within 18-
24 months of injury. In such circumstances , tendon transfers should
be considered.
When neighboring tendons are intact and if all criteria for
tendon transfer met ,then tendon transfer is treatment of choice
55. T
endon Transfer
Tendon transfer should be delayed for 6 months
a) Low MedianNerve:
- Re-routing of ring/ middle finger Flexor Digitorum Superficialis
to APBto aid thumb opposition
b) High MedianNerve:
- Suturing of profundus tendons to ring and small finger tendons
for restoration of IPjoint movements
56. Criteria for tendon transfer
Muscle power grade 5(preferably),if not atleast grade 4
Should haveits own nerveand blood supply
Synergisticgroup are chosenbecauseof easier rehabilitation
Diseaseshould not progress and infection to be controlled
Prior to transfer joint stiffness,contracture and malunion are
corrected
Tendontransferred should not be at anacute angle
57. Restoring thumb opposition:
Thumb opposition is a complex movement that involves palmar
abduction, pronation, and flexion of the thumb metacarpal and
proximal phalanx.
The ideal insertion for an opposition transfer is the APB
insertion. Insertion at this point most reliably causes the
combination of movements that result in thumb opposition.
The angle of pull should be from the location of the pisiform,
because this approximates the normal direction of pull of the
APB.
58. The Superficialis Opponensplasty
Involves dividing the ring finger FDSdistally in
the finger, retrieving the FDS proximal to the
carpal tunnel, re-directing the tendon distally
through the FPL sheath, and inserting it into
the thumb.
The main disadvantage of the superficialis
opponensplasty is that it can only be used in
cases of low median nerve palsy, because the
FDSis paralyzedin high median nervepalsy
59. The EIP(extensor indicis propius)
opponensplasty
The most commonly employed opposition transfer in high median
nervepalsy
The Huber Transfer
EmploysThe Ulnar Nerve-innervatedAbductor Digiti Minimi
(ADM) To Restore Opposition
Camitz Procedure
PLtransfer effectively restores palmarabduction, the
pronation and flexion components of opposition are not re-
established.
60. Tendon transfers
Other procedures
In cases of high median nerve injury, thumb IPJ flexion and index
finger DIPJ flexion can be restored with transfer of the BR, the
ECRL,or ECU.
The most common transfers are BR to FPL and ECRL to index
FDP
.
ECU re-routing and attachment to dorsal radius/Transfer of
biceps insertion from medial to lateral radius for weak forearm
pronation
62. Nerve transfers
Median recurrent neurotisation for high median
nervepalsy
Ulner-median nerve transfer(3rdlumbricle branch to
recurrent median nerve branch transfer)
Radial-median nerve transfer (PIN branches to
Recurrent median nerve branch transfer)
63. Sensory restoration for median nerve
Essential for fine motor tasks,motor recovery
is dependant on the quality of sensations, some
believe it aprerequisite for motor restoration
64. Nerve transfers
Nerve transfers for restoration of flexion in high
median nerve palsy ECRB branch of the radial
nerve to the AIN transfer without grafts
65. Prognosis
Prognosis of nerve regeneration dependsupon severalfactors
Typeoflesion:
Neuropraxia always recovers fully,axonotmesis may or may not,neurotmesis will not
unlessthe nerve isrepaired
Level oflesion
Thehigherthe lesion the worsethe prognosis
Typeofnerve
Purely motor or purely sensory nerves recover better than mixed nerves,because there is
less likelihood ofaxonal confusion.
Condition ofnerve ends
Nerve ends should be prepared in such away that satisfactoryfascicular pattern is
apparent in both proximal and distal stumps.
No scar, foreign material or necrotic tissue should be allowed to remain about the ends to
interfere with axonal regeneration.
66. Prognosis
Sizeofgap
Above the critical resection length ,suture is not successful
Age
Children do better than adaults .Old people do poorly
Delay insuture
The best results are obtained with early nerve repair, after few months , recovery following
suture becomes progressively lesslikely.
Associatedlesions
Damage to vessels , tendons and other structures makes it more difficult to obtain
recovery of auseful limb even if the nerve itself recovers.
Surgicaltechniques
Skill , experience and suitable facilities are needed to treat nerve injuries
68. Carpel Tunnel Syndrome
• It’s aclinical diagnosis
• Results fromcompression of
the median nerve at the
wrist
CTSFirst described by Sir JamesPaget
69. Anatomy - Carpal Tunnel
The bony borders are: radially,
the tubercle of the scaphoid and
the tubercle of the trapezium;
ulnarly the triquetrum, pisiform
and hook of the hamate.The
lunate lies in the floor of the
tunnel.
• 9 tendons runthrough the tunnel:
the 4 FDS, the 4 FDP
,and FPL.
FCR runs in aseparate fascial
compartment onthe radial sideof
the tunnel.
71. Clinical Features:
Hand and wristPain
Numbness and tingling in thumb and index and
middle fingers
Sparing ofPalmar cutaneous branch supply
Patient wakes at night with burning or aching
pain and shakes the hand to obtain relief and
restore sensation
Aggravatedby elevation of hand
Difficulty in holding on to a glass or cup
securely
Thenar atrophy and weakness of thumb
opposition and abduction may develop late
73. Signs of CTS
Thenar muscle wasting due to continued pressure
74. Phalen’s test
Phalen’stest
Patients is askedto
actively place the wrist
in complete but forced
flexion
+ve if tingling and
numbness is produced
in 60sec.
Sensitive and
specific in80%
75. Median Compression test/ Durkan’s
test
Median nerve
compression test
Direct pressure is exerted
over bothwrist 1st phase
–timetaken
for symptomsappear(15-
20sec)
2nd phase-time taken for
symptoms to disappear
after releaseof pressure
76. Tourniquet test
BPcuff tied proximal to elbow and inflated higher
than patient’s Systolic BP
.
+ve ifnumbness and paraesthesia
Scratch Collapse Test
Applyingastimulusovertheareaofnervecompression
whilethepatientisexertingB/Lshoulderrotation,transient
lossofmuscleresistanceresultinginarmcollapsing.
79. Steroid Injection
•Transient relief occurs in 80% of patients
after steroid injection
•But only 22% of patients with steroid
injections are pain free at 12months
(These patients were also splinted).
–It is most useful early in the disease,
when there has been less than 1yr of
symptoms
–there is no weakness or thenar atrophy
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80. Orthoses
Thefollowing orthoses help manage the carpal
tunnel syndromepain:
–Wrist handorthosis
–Thumb spicasplint
–Cock-up wristsplint
81. Orthotics goals
Decrease pain andswelling
Prevent deformity progression
PreventMovement
Byrestrict flexion movement of wrist
Main objective is to position wrist in neutral
but preferably slight extension to get
pressureoff of median nerve
82. SURGERY
Should be considered in patients with symptoms that do not
respond to conservative measuresand in patients with severe
nerve entrapment
It is important to note that surgery may be effective even if a
patient hasnormal nerve conduction studies
Methods ofSurgery
OpenCarpalTunnel Release
EndoscopicCarpalTunnel Release
85. Pronator Syndrome
-Proximal Forearm Compression
- BecauseOf:-
ligament ofStruthers,
Bicipital Aponeurosislacertus fibrosus,
Fibrous Band of pronator teresmuscle
-Due to repetitive and stenuous work with the arm in
pronated positin-computer workers and manual labourers
86. ClinicalFeatures:
Volar Forearm Pain
Sensorydisturbances
-Thumb & Index >Middle finger
Night pain is unusual and forearm pain ismore common
Hand numbness ongripping
Phalen’s testnegative
Symptoms provoked by resisted elbow flexion with
forearm supinated ( tightening of bicipital aponeurosis )-
Pronator Teres Test
88. Anterior Interosseous Syndrome
(Kiloh-Nevin Syndrome)
Involvement of theAnterior InterosseousNerve only
Causes
•Compression from Tumor or ganglion
•Tendons from flexor digitorum to flexor policis longus
•Accessoryhead of flexor policis longus (gantzer
muscle)
•Aberrant radialartery
89. Clinical Features:
Weaknessof the gripping movement of the thumb andindex finger( unableto
makeok -inability to flex either the thumb interphalangeal joint or the index-
finger distal interphalangeal joint
In contrast to those with pronator syndrome, thesepatients donot complain
of numbnessor pain
90. REFERENCES:
Last’s Anatomy, 12th Edition
Greens’ Operative Hand Surgery, 6th Edition
Apleys and Solomon’s System of Orthopedics
Miller’s Review of Orthopedics, 8th Edition
Ligament of struthers : It is seen 5 cm proximal to the medial epicondyle and is a fibrous band that interconnects a bony spur on the distal humerus to the medial epicondyle
Lesion Location: Proximal (near the elbow)
Deficiency: When the patient tries to make a fist, they are unable to flex the index and middle fingers due to loss of lateral lumbrical action, leading to the hand of benediction. The fingers are extended due to unopposed radial nerve action on the finger extensors.
Both flexor digitorum superficialis(FDS) and ProfundusFDP) of Index finger paralysed but in middle finger some amount of flexion is possible because of common muscle belly with ring and little finger
This lesion is related to ape hand due to the fact that loss of opponens pollicis means one has an unopposable thumb (like an ape). It seems some also believe the term ape hand refers to the thenar atrophy.
The patient’s forearm is extended and fully pronated. The patient is then instructed to resist supination of the forearm by the examiner.
The patient flexes the wrist along the trajectory of the forearm.
To test proximal interphalangeal joint flexion, the supinated forearm and hand are placed straight. Each finger is tested separately. Placing the fingers between the single finger to be tested and the remaining fingers that are immobilized isolates this movement. This maneuver places the finger to be tested in mild flexion at the metacarpal– phalangeal (knuckle) joint, and stabilizes the remaining fingers in extension, a position that allows isolation of the flexor digitorum superficialis.
To assess the median innervation of the flexor digitorum profundus one should concentrate on the index finger. To do so, holding the metacarpal-phalangeal and proximal interphalangeal joints immobile, and have the patient flex the distal phalanx against resistance.
Immobilize the thumb, except the interphalangeal joint, and then ask the patient to flex the distal phalanx against resistance.
A quick way to assess the flexor digitorum profundus and flexor pollicis longus innervation from the anterior interosseous nerve is to ask the patient to make an okay sign by touching the tips of the thumb and index finger together.
With weakness in these muscles, the distal phalanges cannot flex, and instead of the fingertips touching, the volar surfaces of each distal phalanx make contact
Have the patient resist supination of a fully flexed and pronated forearm. With full forearm flexion, pronation by the usually dominant pronator teres is minimized
Resist movement of the thumb away from the plane of the palm (palmar abduction),while stabilizing the metacarpals of the remaining fingers.
The patient flexes the thumb at the metacarpalphalangeal joint against resistance placed over both the proximal and distal phalanges.
Make certain the distal interphalangeal joint does not flex because in allowing this, substitution by the flexor pollicis longus occurs.
Use other hand to immobilize the first metacarpal to reduce substitution by the opponens pollicis.
Have the patient forcibly maintain contact between the volar pads of the distal thumb and fifth digit, while try to pull the distal first metacarpal away from the fifth digit. Although thumb opposition is only innervated by the median nerve, a combination of thumb adduction (adductor pollicis, ulnar nerve) and thumb flexion (flexor pollicis brevis, deep head, ulnar nerve) may mimic thumb opposition even when there is complete median nerve palsy present
Stabilize the patient’s index finger in a hyper- extended position at the metacarpal-phalangeal joint and then provide resistance as the patient extends the finger at the proximal interphalangeal joint.
Tested by gentle percussion along course of nerve from distal to proximal direction.
Tingling sensation felt by patient in distribution of nerve.
Tingling should persist for several seconds
This is most likely when there is a proximal injury in a nerve supplying distal muscles.
MNEMONIC
PRAGMATIC
P-PREGNANCY
R-RHEUMATOID ARTHRITIS
A-ATHRITIS DEGENERATIVE
G-GROWTH HORMONE EXCESS
i.e. ACROMEGALY
M-METABOLIC i.e. GOUT
A-ALCOHOLISM
T-TUMORS
I-IDIOPATHIC
C-CONNECTIVE TISSUE DISORDER i.e. AMYLOIDOSIS
Night numbness is caused by a number of factors:
Horizontal position results in a redistribution of fluid to the upper limbs
Drainage by the action of the muscle pump is
diminished
There is a tendency towards wrist flexion at night
The blood pressure drops during late night and early morning, resulting in decreased perfusion pressure
Differential Diagnoses of CTS:
Tendonitis
Tenosynovitis
Diabetic neuropathy
Kienbock's disease
Compression of the Median nerve at the elbow