The brachial plexus forms from cervical and thoracic nerve roots and supplies the upper limb. It is vulnerable to injuries which can cause syndromes like Erb's palsy (affecting shoulder and arm muscles) or Klumpke's paralysis (affecting hand muscles). Peripheral nerve injuries are classified and specific tests examine individual nerve function by assessing related muscle strength and sensation. The median and radial nerves were discussed in detail regarding their anatomy and clinical assessments.

1. BRACHIAL PLEXUS AND
PERIPHERAL NERVES
• ROLL NO : 1821 - 1830

2. • Brachial plexus is network of nerves that supply
sensation and motor function to upper extremity
• Formed by ventral primary rami of lowest four
cervical and upper most thoracic nerve ( c5-T1)

3. Anatomy
• Roots -
• Trunks –
• Division-
• Cords –
• Branches
c5 – t1
Upper ,middle and lower
Anterior and posterior
Medial, posterior and lateral

5. Branches
• Roots -
Long thoracic nerve – serratus anterior
dorsal scapular nerve - rhomboidus ,
levator scapulae
• Trunk -
suprascapular nerve – supraspinatus
Infraspinatus
Nerve to subclavius

6. Branches of cord
• Lateral cord
lateral pectoral nerve
musculocutaneous nerve and contribute to
median nerve
• Medial cord
medial cutaneous nerve of arm , medial
cutaneous nerve of forearm , medial pectoral
nerve
median nerve contribution and ulnar nerve.

7. • Posterior cord
upper and lower subscapular nerve
Thoraco-dorsal nerve
Axillary and radial nerve

8. ERB’s POINT AND ERB’s PALSY-
• Erb’s point is the meeting point of the 6 nerves

9. • Injury to Erb’s point leads to Erb’s palsy
Common causes of injury to Erb’s point:
• Direct fall on shoulder
• Obsteric complications

10. Nerves and muscles affected in Erb’s palsy:
• Suprascapular nerve-supraspinatus and infraspinatus muscles
• Radial nerve- brachioradialis, extensor carpi radialis longus and supinator
muscles
• Musculocutaneous nerve- biceps brachii and brachialis muscles
• Axillary nerve- deltoid and teres minor muscles
• Nerve to subclavius- subclavius muscle

11. Deformity of Erb’s palsy(policeman’s tip
deformity):
• Cause- paralysis of the abductor and
external rotators of the shoulder
alongwith flexors and supinators of the
elbow
• Shoulder joint- adducted and medially
rotated
• Elbow joint- extended
• Forearm- pronated

12. KLUMPKE’s PARALYSIS( CLAW HAND)-
• Cause –lower trunk injury(C8, T1)
• Nerves affected- ulnar nerve and median
nerve
• Muscles affected- small muscles of the
palm
• Deformity –hyperextension of
metacarpopharyngeal joints + flexion of
interphalangeal joints

13. Structure of peripheral nerve
Peripheral nerve consist of -
1.axon
2. Connective tissue
Endoneurium - an individual nerve fibre is enclosed in a
collagen connective tissue.
Perineurium - bundle of nerve fibre are bound together
by fibrous tissue to form fasciculus .
Epineurium - no. of fasciculi are bound together by a
fibrous tissue sheath.

14. Anatomical features relevant to nerve injuries
There are some feature related to the anatomy of a nerve which
make a particular nerve more prone to injury. These are follows :
A. Relation to the surface :
superficially placed nerves are more prone to injury by external object
Eg. The median nerve at the wrist often get cut by a piece of glass .
B. Relation to bone :
nerve in close proximity to a bone or joint are more prone to injury.
Eg. Radial nerve injury in a fracture of the shaft of the humers .

15. C. Relation to fibrous septae : some nerve pierce fibrous sepate along
their course . they may get entrapped in these sepate .
D. Relation to major vessels : nerve in close relation to a major vessel run
the risk of ligation during surgery , or damage by an aneurysm .
E. Course in a confined space : A nerve may travel in a confined fibro -
osseous tunnel and get compressed if there is a compromise of the space .
Eg . median nerve compression in carpel tunnel syndrom .
F. fixation at point along the course : nerves are relatively fixed at some
points along their course and do not tolerate the strench they may be subject
to eg . the common peroneal nerve is relatively fixed over the neck of the
fibula , and any strenching of the sciatic nerve often leads to isolated damage
to this component of the nerve .

16. Most common cause - fracture & dislocation .
Other mechanism -
● direct injury - cut , laceration
● Infection - leprosy
● Mechanical injury - compression ,traction ,friction & shock wave
● Thermal injury
● Electrical injury
● Ischemic injury - volkman’s ischemia
● Toxic agent - tetracycline injection
● Radiation for - cancer treatment

17. Pathology of peripheral nerve
Three basic pathological process-
● Wallerian degeneration
● Axon degeneration
● Demyelination
1. Wallerian degeneration -
degenerative changes occure in
the part of neuron which is distal to
the part of injury .

18. -regeneration occure by sprouting of axon & proliferation
of schwan cell from the proximal segment .
2. Axonal degeneration -
Most common pathological reaction of peripheral nerve.
Caused by - systemic metabolic disorder ,toxin exposure
and some inherited neuropathies.
-myelin sheath break down along with axon, in a process
that start at the distal part of nerve fibre & progress toward
the nerve cell body.

19. 3. Segmental demyelination -
segmental destruction of myelin sheath occurs
without axonal damage .
-Occure in immune mediated demyelinating
neuropathies

20. Classification of nerve injury
1824

22. Seddon's classification: Seddon classifies nerve injuries into
three types: (i) neurapraxia; (ii) axonotmesis; and (iii)
neurotmesis.
• Neurapraxia: It is a physiological disruption of conduction in
the nerve fibre. No structural changes occur. Recovery occurs
spontaneously within a few weeks, and is complete.
• Axonotmesis: The axons are damaged but the internal
architecture of the nerve is preserved. Wallerian degeneration
occurs. Recovery may occur spontaneously but may take
many months. Complete recovery may not occur.
• Neurotmesis: The structure of a nerve is damaged by actual
cutting or scarring of a segment. Wallerian degeneration
occurs. Spontaneous recovery is not possible, and nerve
repair is required.

23. DIAGNOSIS
In a case of peripheral nerve injury, the following information
should be obtained by careful history and examination:
a) Which nerve is affected?
b) At what level is the nerve affected?
c) What is the cause?
d) What type of nerve injury (neurapraxia etc.) is
it likely to be?
e) In case of an old injury, is the nerve recovering?

24. History: A patient with a nerve injury commonly presents with
complaints of inability to move a part of the limb, weakness and
numbness. The cause of nerve injury may or may not be obvious.
In case the cause is obvious, say a penetrating wound along the course
of a peripheral nerve (e.g., glass cut injury to the median nerve), the
nerve affected and its level is easy to decide. Similarly, nerve injury may
occur during an operation as a result of stretching or direct injury.
When the cause is not obvious, an inquiry must be made regarding any
history of injection in the proximity of the nerve. Neurotoxic drugs such
as quinine and tetracycline are known to damage nerves. Medical
causes of nerve affection like leprosy, diabetes should be considered in
patients who do not give a history of injury.

25. WHICH NERVE IS AFFECTED?
Attitude and deformity: Patients with some peripheral nerve injuries present with
a classic attitude and deformity of the limb. Some such attitudes in different nerve
injuries are as follows: • Wrist drop: The wrist remains in palmar flexion
due to weakness of the dorsiflexors. It is seen in radial nerve palsy.
• Foot drop: The foot remains in plantar flexion
due to weakness of the dorsiflexors. It occurs in
common peroneal nerve palsy.
• Winging of scapula: The vertebral border of the
scapula becomes prominent when the patient tries to push against a wall. It occurs in
paralysis of the serratus anterior muscle in long thoracic nerve palsy.

26. Claw hand.
‘Ape thumb’ deformity: In this deformity the thumb is in the same
plane as the wrist. It occurs due to paralysis of the opponens pollicis
muscle in median nerve palsy.
‘Pointing index’: On asking the patient to make a fist, it is noticed that
the index finger remains straight. This is due to paralysis of both the
flexors (digitorum superficialis and lateral half of the digitorum profundus)
of the index finger, which occurs in median nerve palsy at a level
proximal to the elbow. The other fingers can be flexed by the functioning
medial side of the flexor digitorum profundus, supplied by the ulnar
nerve.
‘Policeman tip' deformity

27. Wasting of muscles: This will be obvious some time after the paralysis. It may
be slight and become apparent only on comparing the affected limb with the sound
limb. Some examples of this are given in

28. Skin: The skin becomes dry (there is no sweating due to the involvement of the
sympathetic nerves), glossy and smooth. In partial lesions, there may be vasomotor
changes in the form of pallor, cyanosis, or excessive sweating. There may be
trophic disturbances such as ridged and brittle nails, shiny atrophic skin, trophic
ulcers etc.
Temperature:A paralysed part is always colder and drier because of loss of
sweating, best appreciated by comparing it with normal skin.

29. Sensory examination: The different forms of sensation to be tested in a suspected
case of nerve palsy are touch, pain, temperature and vibration. The area of sensory
loss may be smaller than expected. If it is so, look for sensation in the autonomous
zone
Reflexes: Reflexes in the area of nerve distribution are absent in cases of peripheral
nerve injuries.
Sweat test: This is a test to detect sympathetic function in the skin supplied by a
nerve. Sympathetic fibres are among the most resistant to mechanical trauma. The
presence of sweating within an autonomous zone of an injured peripheral nerve
reassures the examiner that complete interruption of the nerve has not occurred.
Sweating can be determined by the starch test or ninhydrin print test. In these tests,
the extremity is dusted with an agent that changes colour on coming in contact with
sweat.

30. Motor examination: For evaluation of motor functions, clear concepts about
the anatomy, as to which nerve supplies which muscle is essential. The muscles
which are exclusively supplied by a particular nerve are most suitable for motor
examination. The tests are nothing but manoeuvres to make a muscle contract.
One must carefully watch for trick movements—the movement produced by the
adjacent muscles, often substituting for the paralysed muscle. The contraction of
the muscle must be appreciated, wherever possible, by feeling its belly or its
tendon getting taut.

31. Radial Nerve

32. Anatomical Course
●Continuation of the Posterior cord of Brachial Plexus
●In axilla, gives off motor branch to long head of triceps.
●In arm, gives posterior cutaneous nerve of arm and branch to medial
head of triceps.
●In groove on posterior surface of humerus, gives motor branches to
lateral head of triceps, anconeus and cutaneous branch to arm and
forearm.
●After radial groove and before crossing elbow, pierces lateral
intermuscular septum from behind, lies between brachialis muscle
on medial side and brachioradialis and extensor carpi radialis longus
on lateral side.

33. ●Before crossing elbow in front of lateral condyle,
divides into 2 branches – superficial and deep
branch.
Superficial one is sensory and runs along side
radial artery in forearm.
Deep branch is motor, gives branches to extensor
carpi radialis brevis and supinator.
●After piercing supinator, emerges into posterior
compartment of forearm and becomes posterior
interosseous nerve. It supplies extensor muscles
of forearm and muscles of hand.

35. Level of injury to radial nerve
Muscles supplied by radial nerve will be affected depending on
the level of injury.
1. High radial nerve palsy : occurs if nerve is injured in radial
groove.
All muscles except the triceps and anconeus are paralysed.
Very high radial nerve palsy : Nerve injury slightly high up of
radial groove, triceps are also paralysed.
2. Low radial Nerve injury : Occurs if nerve injured around elbow
so that muscles supplied in distal arm (brachioradialis, extensor
carpi radialis longus and brevis) are spared.

36. Tests
●Triceps: Patient is asked to extend his elbow against resistance
applied by examiner, whose other hand feels for triceps
contraction.
●Wrist extensors: The patient with paralysed wrist extensors has
wrist drop. In case the paralysis is partial, the contraction of
extensor carpi radialis and extensor carpi ulnaris muscle can be
felt, though actual movement may not occur.
●Brachioradialis : The patient is asked to flex the elbow from 90
degree onwards, keeping the forearm mid prone. As he does so
against the resistance, brachioradialis stands out and can be
felt.

37. ●Extensor digitorum : It causes extension at the metacarpophalangeal
joints. The patient cannot do so if it is paralysed (finger drop).
●Extensor pollicis longus : This causes extension at interphalangeal
joint of the thumb.
The metacarpophalangeal joint of thumb is stabilized, while patient is
asked to extend the interphalangeal joint.

38. Median nerve:
Anatomy: This nerve is formed by the joining of branches
from the lateral and medial cords of brachial plexus. In the
arm, the median nerve descends adjacent to the brachial
artery.
Course in the forearm:
❖ The nerve enters the forearm between the two heads
of the pronator teres.
❖ It then passes deep to the tendinous bridge of the origin
of the flexor digitorum superficialis, in the proximal third
of the forearm.
❖ In the mid forearm it descends between the flexor
digitorum superficialis and flexor digitorum profundus.

39. ❖ About 5cm above the wrist, it comes to lie on the lateral side
of the flexor digitorum superficialis.
❖ It becomes superficial just above the wrist, where it lies
between the tendons of the flexor digitorum superficialis and
flexor carpi radialis.
Course in the hand:
❖ The nerve passes deep to the flexor retinaculum and enters
the palm.
❖ Here a short and stout muscular branch from it supplies the
muscles of the thenar eminence(abductor pollicis brevis,
opponens pollicis and flexor pollicis brevis).

40. ❖ The median nerve finally divides into 4 to 5 palmar digital branches
supplying the area of skin.
❖ Also,motor branches
are given to the first and
second lumbrical muscles
at this level.
❖ The nerve supply to
various muscles by the
median nerve along its
course is given in table
10.4.

41. Tests: The various muscles supplied by the median nerve will be
affected according to the level of median nerve injury i.e. high or
low.
A) High median nerve palsy (injury proximal to the elbow): This will
cause paralysis of all the muscles supplied by the median nerve
in the forearm and hand. In addition, there will be sensory
deficit in the skin of the hand.
B) Low median nerve palsy (injury in the distal third of the
forearm): There will be sparing of the forearm muscles, but the
muscles of the hand will be paralysed. In addition, there will be
anaesthesia over the median nerve distribution in the hand.

42. From proximal to distal, the following muscles can be examined.
● Flexor pollicis longus: The patient is asked to flex the terminal
phalanx of the thumb against resistance while the proximal
phalanx is kept study by the examiner.
● Flexor digitorum superficialis and lateral half of flexor
digitorum profundus: If the patient is asked to clasp his hand,
the index finger will remain straight, the so called ‘pointing
index’. This occurs because both the finger flexors,
superficialis as well as the profundus of the index finger are
paralyzed; though the available medial-half of the flexor
digitorum profundus(supplied by the ulnar nerve) makes
flexion of the other fingers possible.

43. ● Flexor carpi radialis: Normally, the palmar flexor at the wrist
occurs in the long axis of the forearm. In a patient with paralyzed
flexor carpi radialis, the wrist deviates to the ulnar side while
palmar flexion occurs. In addition one cannot feel the tendon of
the flexor carpi radialis getting taut.
● Muscles of the thenar eminence: Out of the three muscles of the
thenar eminence, only two can be examined for their isolated
action. These are as follows:(i) abductor pollicis brevis: the action
of this muscle is to draw the thumb forwards at right angle to the
palm. The patient is asked to lay his hand flat on the table with
palm facing the ceiling. A pen is held above the thumb and the
patient is asked to touch the pen with tip of his thumb. This is
called the ‘pen test’.

44. (ii) opponens pollicis: The function of this muscle is to appose the
tip of the thumb to other fingers. Apposition is a swinging
movement of the thumb across the palm and not a simple
adduction. The latter movement is by the adductor pollicis muscle
supplied by the ulnar nerve.

45. ULNAR NERVE

46. MAJOR MOTOR BRANCHES OF ULNAR NERVE

47. HIGH AND LOW LEVEL ULNAR NERVE PALSY
a) High ulnar nerve palsy (injury proximal to the elbow): This will
cause paralysis of all the muscles supplied by the ulnar nerve in the
forearm and hand. In addition, there will be a sensory deficit in the
skin of the hand.
b) Low ulnar nerve palsy (injury in distal-third of forearm): There will
be sparing of forearm muscles but the muscles of the hand will be
paralysed. Sensory deficit will be same as in high ulnar nerve palsy.

48. EXAMINATION OF INDIVIDUAL MUSCLE:-
Flexor carpi ulnaris: The patient is asked to palmar flex the wrist against
gravity. In doing so, the hand deviates towards the radial side. The
tendon of flexor carpi ulnaris just above the pisiform, does not stand
out. On performing the same test against resistance, the tendon cannot
be felt.

49. Interossei: Palmar interossei do adduction (PAD), the dorsal interossei
do abduction (DAB) of the fingers at metacarpo-phalangeal joints.
Tested by:-
This is for dorsal interossei
(abductors) of the middle finger.
With the hand kept flat on a
table palmar surface down, the
patient is asked to move his
middle finger sideways.
1)Egawa's test

51. Adductor pollicis:
The patient is asked to grasp
a book between the thumb and index finger.
Normally, a person will grasp the book firmly
with thumb extended, taking full advantage
of the adductor pollicis and the first dorsal
interosseous muscles. If the ulnar nerve is
injured, the adductor pollicis will be paralysed
and the patient will hold the book by using
the flexor pollicis longus (supplied by median
nerve) in place of the adductor. This produces
flexion at the inter-phalangeal joint of the thumb.

52. Accessory Nerve
-supply the trapezius muscle
Test:
- by asking the patient to elevate his shoulder against resistance . The
examiner can see and feel the trapezius belly stand out.
The patient is asked to brace his shoulder backward and depress it to
examine middle and lower part of muscle.

53. Long thoracic nerve
Anatomy :
-arises from the ventral rami of C5, C6, C7.
-descends behind the brachial plexus and supplies to the Serratus
anterior.
Test : by asking the patient to push against the wall with both hands. The
medial border of the affected side will become prominent. (winging of
scapula)

54. Axillary nerve
Anatomy:
-arises from posterior cord of the brachial plexus and curves backwards on
the lower border of subscapularis.
-It crosses the quadrangular space and comes lie on the medial side of
neck of humerus, medial and inferior to the capsule of shoulder.
Posterior branch – teres minor and posterior part of deltoid
Anterior branch – rest of deltoid.
Test : The scapula is stabilised with one hand and other hand is kept on the
deltoid to feel for its contraction. The patient is asked to abduct his
shoulder. Inability to abduct the shoulder, and the absence of the deltoid
becoming taut indicates deltoid paralysis.

55. Sciatic nerve
Anatomy : arises from the lumbosacral plexus and consists of two
components –
1. Common peroneal nerve –extensors and evertors of foot.
Paralysis of these muscle results in foot drop.The patient walks with a “high-
step gate”i.e the patient lift the foot high in order to clear the ground.
2.Tibial nerve -planter flexors of the foot.
test : by asking the patient to plantar-flex the ankle and toes.
Hamstring muscle is also supplied by sciatic muscle and can be tested by
flexing the knee against resistance

56. Causes of nerve injury-
-Displaced bone fragments
-Thickening of nerve (e.g leprosy)
-traction injury to the shoulder
-closed blunt trauma
-medical condition (e.g diabetes)
-Autoimmune disease(s e.g lupus, rheumatoid arthritis)

57. Signs of regeneration
Tinel’s sign : on gently tapping over the nerve along its
course, from distal to proximal, a pins and needle sensation
is felt in the area of skin supplied by the nerve. A distal
progression of the level at which this occurs, suggest
regeneration.
Motor examination: The muscle supplied nearest to the site
of injury is first to recover and is noticed clinically by the
ability of the muscle to contract.
Electrodiagnostic test : this can help in predicting nerve
recovery even before it is apparent clinically.

73. Treatment
 In fresh nerve injuries,the general condition of the patient must be
evaluated before undertaking a nerve repair
 Arterial, bone and joint repair is done before nerve repair
 The treatment of nerve injuries may be:- CONSERVATIVE & OPERATIVE

74. CONSERVATIVE TREATMENT:
 The aim of conservative treatment is to preserve the mobility of the
affected limb while the nerve recovers
 Essential components of conservative treatment are:-
1. Splintage of the paralysed limb:-The first procedure to be adopted in
every case of nerve injury is to splint the limb in the position which will
most effectively relax the affected muscles
2. Preserve mobility of the joints:-Every joint of the affected limb must be
put through full range of movement {at least once every day}
3. Care of the skin and nails:-Skin should be protected from trauma, burn
or pressure sores. Nails should be cleaned and cut with care

75. 4.Physiotherapy: (i)massage of the paralysed muscles; (ii)passive exercises to
the limb; (iii)building up of the recovering muscles; (iv)developing the
unaffected or partially affected muscles
5.Relief of pain:-Suitable analgesics are prescribed for relief of pain

76. OPERVATIVE TREATMENT:-
It consist of nerve repair,neurolysis and tendon transfers.
Nerve repair:-Primary repair and Secondary repair
 Primary repair:- It is indicated when the nerve is cut by a sharp
object, and the patient reports early
 If the wound is contaminated or the patient reports late, delayed
primary repair is better
 In the first stage,the wound is debrided and the two nerve ends
approximated with one or two fine silk sutures so as to prevent
retraction of the cut ends. After two weeks, when the wound heals,
a definitive repair is done

77. Secondary repair:-It is indicated for the following
cases:
 Nerve lesions presenting some time after injury
 Syndrome of incomplete interruption
 Syndrome of irritation
 Failure of conservative treatment
Techniques of nerve repair:-It can be either end-to-
end or by using a nerve graft
a)Nerve suture:-
 Epineural suture
 Epi-perineural suture
 Perineural suture
 Group fascicular repair

78. b)Nerve grafting:-When the nerve gap is more than 10cm or end-to-end
suture is likely to result in tension at the suture line, nerve gafting may be
done
 In this, an expandable nerve (sural nerve) is taken and sutured between
two ends of the original nerve
Neurolysis:-
External neurolysis:-In this the nerve is freed from enveloping scar
(perineural fibrosis)
Internal neurolysis:-In this the nerve sheath is dissected longitudinally to
relieve the pressure from the fibrous tissue within the nerve (intra-neural
fibrosis)

79. Reconstructive surgery:-
 These opertations are performed when there is no recovery, usually
after 18 months of injury
 Opertations included in this group are:- tendon transfers, arthrodesis
and muscle transfer

80. Prognosis:-
 Age: The lower the age, the better the prognosis
 Tension at suture line: The more the tension,the poorer the prognosis
 Time since injury: After 18 months only sensory function can be expected
 Location of injury:The more proximal the injury,the worse the prognosis
 Type of nerve: A primarily motor nerve, like radial nerve, has a better prognosis than a
mixed nerve
 Condition of the nerve ends:The more the crushing and infection, the poorer the
prognosis
 Associated conditions:Infection, ischaemia etc. indicate poor prognosis

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