Peripheral nerves arise from spinal nerves and branch throughout the body, carrying motor, sensory and autonomous functions to limbs. When injured, patients may experience weakness, numbness or inability to move part of a limb. Peripheral nerve injuries can be caused by penetrating wounds, medical procedures, or neurotoxic agents. On examination, signs may include sensory loss, absent reflexes, muscle wasting or temperature changes in the affected area. Treatment involves splinting, physiotherapy and surgery such as nerve repair or grafts. Recovery depends on factors like the nerve injured, tension at repair site, and time since injury.

1. PERIPHERALNERVEINJURIES
Dr. Harishma Ramesh

2. • These are formed from nerves arising from the spinal cord
(spinal nerves).
• There are 31 pairs of spinal nerves in the body, each
representing a segment of the spinal cord.
• Through direct branching or through a network of nerves
(plexus), give rise to peripheral nerves.
• Peripheral nerves are mixed nerves carrying motor, sensory and
autonomous supply to the limbs.
PERIPHERAL
NERVE

3. STRUCTURE
OF
A
PERIPHERAL
NERVE
• An individual nerve
fi
bre is enclosed in a collagen connective tissue
known as endoneurium.
• A bundle of such nerve
fi
bres are further bound together by
fi
brous
tissue to form a fasciculus. The binding
fi
brous tissue is known as
perineurium.
• A number of fasciculi are bound together by a
fi
brous tissue sheath
known as epineurium.
• An individual nerve, therefore, is a bundle of a number of fasciculi.

4. A p
a
tient with
a
nerve injury commonly
presents with compl
a
ints of
In
a
bility To Move A P
a
rt Of The Limb
We
a
kness
Numbness.
History

5. CAUSE
History
OBVIOUS
• penetr
a
ting wound
a
long the
course of
a
peripher
a
l nerve
• nerve injury m
a
y occur during
a
n oper
a
tion
a
s
a
result of
stretching or direct injury
NOT OBVIOUS
• History of injection in the
proximity of the nerve.
• Neurotoxic drugs such
a
s
quinine
a
nd tetr
a
cyclines.
• Medic
a
l c
a
uses - leprosy,
di
a
betes

6. MECHANISM
OF
INJURY
MCC - Fractures and dislocations
Mechanisms by which a nerve may be damaged are:
• Direct Injury
• Infections
• Mechanical Injury
• Cooling And Freezing
• Thermal Injury
• Electrical Injury
• Ischaemic Injury
• Toxic Agents
• Radiation

7. • Skin: The skin becomes dry (there is no
sweating due to the involvement of the
sympathetic nerves), glossy and smooth.
• Temperature: A paralysed part is usually colder
and drier because of loss of sweating, best
appreciated by comparing it with normal skin.
• Sensory examination: The di
ff
erent 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.
WASTING OF MUSCLE
ONEXAMINATION

8. • Re
fl
exes: Re
fl
exes 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
fi
bres are among the most resistant to mechanical trauma.
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.
WASTING OF MUSCLE
ONEXAMINATION

9. • Motor examination:
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.
The contraction of the muscle must be
appreciated, wherever possible, by feeling its
belly or its tendon getting taut.
WASTING OF MUSCLE
ONEXAMINATION

10. We Will Discuss Individual Nerve Injury…

11. NERVE FUNCTION ACTION PRESENTATION TESTS/ EXAMINATION SPILNT
Axillary
MOTOR :
Deltoid
Teres minor
• Abduction of
shoulder
• External rotation
of shoulder
• Flat shoulder
Adduction
+
Internal rotation
• Wasting of
deltoid
Stabilise the scapula
with one hand while
other hand is kept on
deltoid to feel for its
contraction.
Patient is asked to
abduct his/her
shoulder
Inability to abduct
shoulder and absence
if deltoid becoming
taunt
Abduction
splint
Aeroplane
splint
SENSORY:
Deltoid
Regimental
badge sign
AXILLARYNERVE

12. AXILLARYNERVE

13. NERVE FUNCTION ACTION PRESENTATION
Musculocutaneous
MOTOR
Coracobrachialis
Brachialis
Biceps brachii
• Flexion of the arm at
elbow
• Supination of the
forearm
Weak
f
lexion at shoulder
Weak supination
Wasting of biceps
SENSORY:
Lat. aspect of forearm
Sensory loss along the lateral side of
the forearm
MUSCULOCUTANEOUSNERVE

14. NERVE FUNCTION ACTION PRESENTATION
TESTS/
EXAMINATION
TREATMENT
MEDIAN /
LABOURERS
NERVE
MOTOR
Ant. Compartment
of forearm
Thenar
Lumbricals - 1,2
Abduction
Flexion
Opposition
Hand of
benediction
Ape thumb
deformity
Wasting of thenar
eminence
• Pen test
• Pointing index
test
• Ok sign
SPLINT :
Opponens splint
SENSORY
Volvar aspect: 3 &1/2
Dorsal aspect: 1,2,3
MEDIANNERVE

16. NERVE MUSCLES SUPPLIED ACTION PRESENTATION
TESTS/
EXAMINATION
SPLINT
ULNAR/
MUSICIAN
NERVE
MOTOR:
Hypothenar
Lumbricals 3,4
Flexor carpi ulnaris
Flexor digitorum
profundus
Palmar and dorsal
interossei
• Finger adduction
and abduction
other than
thumb
• Thumb
adduction
• Flexion of 4,5
digits
• Flexion of wrist
and adduction
Claw hand
deformity
Wasting of
hypothenar
eminence and
intrinsic muscles of
hand
1. Card test
2. Egawa tes
3. Book test
Knuckle bender
splint
SENSORY:
Medial 1 1/2
ULNARNERVE

19. NERVE MUSCLES SUPPLIED ACTION PRESENTATION SPLINT
RADIAL
NERVE
MOTOR:
Post. Compartment of arm - triceps brachia
Post. Compartment of forearm
Wrist extensors
Finger extensors
Brachioradials
Supinator
Extension of elbow,
wrist and
f
ingers
• Wrist drop
• Finger drop
• Thumb drop
• Wasting of triceps and
post. Compartment of
forearm
Cock up
SENSORY:
Lower post. Arm, post. Forearm, lat. 2/3
dorsum of hand, proximal dorsal aspect of
lat. 3 1/2
f
ingers
RADIALNERVE

21. MUSCLES SUPPLIED : Serratus anterior muscle
LONGTHORACICNERVEPALSY
• Winging of scapula
• The vertebral border of the scapula becomes
prominent when the patient tries to push against a
wall.

22. NERVE BRANCHES
MUSCLES
SUPPLIED
ACTION PRESENTATION SPLINT
SCIATIC
Common
peroneal nerve
Extensors
Evertors of foot
Evertion of foot High step gait Foot drop /
ankle foot
orthosis
splint
Tibial nerve
Plantar Flexors
of foot
Plantar
f
lexion
of foot
SCIATICNERVEINJURY

23. THE
TYPE
OF
INJURY

24. Neurapraxia
• It is a physiological
disruption of conduction
in the nerve
fi
bre.
• 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.

26. Nerve
degeneration
Dist
a
l to the point of injury - second
a
ry or W
a
lleri
a
n
degener
a
tion
The proxim
a
l p
a
rt - prim
a
ry or retrogr
a
de degener
a
tion
upto
a
single node.

27. Nerve Regeneration
As regeneration begins, the axonal stump from the proximal segment begins to grow distally.
The r
a
te of recovery of
a
xon is 1 mm per d
a
y
• If the, the axonal sprout may
readily pass along its primary
course and re-innervate the end-
organ.
• motor march
• The sprouts, as many as 100 from one
axonal stump, may migrate aimlessly
throughout the damaged area into the
epineural, perineural or adjacent
tissues to form an end-neuroma or a
neuroma in continuity
Endoneural Tube With Its Contained
Schwann Cells Is Intact
Endoneural Tube Is Interrupted

28. SIGNSOFREGENERATION
Whenever
a
c
a
se of nerve injury is seen some time
a
fter the injury or following
a
rep
a
ir, signs of
regener
a
tion of the nerve should be looked for during ex
a
min
a
tion
• Tinel's sign
• Motor examination
• Electrodiagnostic test

29. Electromyography
• Electromyography (EMG) is a graphic recording
of the electrical activity of a muscle at rest and
during activity.
• Electromyography is useful in deciding the
following:
a) Whether or not a nerve injury is present
b) Whether it is a complete or incomplete nerve injury
c) Whether any regeneration occurring
d) Level of nerve injury
ELECTRODIAGNOSTIC STUDIES
DIAGNOSIS

30. Nerve conduction studies
• It is a measure of the velocity of conduction of
impulse in a nerve.
• A stimulating electrode is applied over a point on the
nerve trunk and the response is picked up by an
electrode at a distance or directly over the muscle.
• The normal nerve conduction velocity of motor nerve
is 70 metres/second.
• This conduction study helps in the following:
a) Whether a nerve injury is present
b) Whether it is a complete or partial nerve injury
c) Compressive lesion
ELECTRODIAGNOSTIC STUDIES
DIAGNOSIS

31. TREATMENT
Conserv
a
tive or Oper
a
tive
CONSERVATIVE TREATMENT
The aim of conservative treatment is to preserve the mobility of the a
ff
ected limb while the
nerve recovers.
The following are the essential components of conservative treatment:
• Splintage of the paralysed limb
• Preserve mobility of the joints
• Care of the skin and nails
• Physiotherapy: Physiotherapeutic measures consist of (i) massage of the paralysed muscles; (ii)
passive exercises to the limb; (iii) building up of the recovering muscles; and (iv) developing the
una
ff
ected or partially a
ff
ected muscles.
• Relief of pain

32. Operative procedures for nerve injuries consist of nerve
repair, neurolysis, and tendon transfers.
OPERATIVE TREATMENT
Nerve rep
a
ir
It may be performed within a few days of injury (primary repair) or later (secondary repair).
Primary repair:
• It is indicated when the nerve is cut by a sharp object, and the patient reports early
(immediate primary repair is the best)
• In case the wound is contaminated or the patient reports late, a delayed primary repair is
better. In this, in the
fi
rst stage, the wound is debrided and the two nerve ends approximated
with one or two
fi
ne silk sutures so as to prevent retraction of the cut ends. This also makes
identi
fi
cation of the cut ends easy at a later date.
• After two weeks, once the wound heals, a de
fi
nitive repair is done. Some surgeons routinely
perform a delayed primary repair because they feel that the epineurium gets thickened in
two weeks and sutures hold better.

33. Secondary repair:
It is indicated for the following cases:
a) Nerve lesions presenting some time after injury: Often nerve injuries are missed at the time of
injury, or it may not have been possible to treat them early for reason, such as poor general
condition of the patient.
b) Syndrome of incomplete interruption: If no de
fi
nite improvement occurs in 6 weeks in cases
with an apparently incomplete nerve injury, nerve exploration, and if required secondary repair
should be carried out.
c) Syndrome of irritation: Cases with signs of nerve irritation need exploration and sometimes a
secondary repair.
d) Failure of conservative treatment: If a nerve injury is treated conservatively and no improvement
occurs within 3 weeks, one should proceed to electrodiagnostic studies, and if required, nerve
exploration.
Nerve rep
a
ir
It may be performed within a few days of injury (primary repair) or later (secondary repair).

34. Techniques of nerve repair
Nerve suture
When the nerve ends can be brought close to each
other, they may be sutured by one of the following
techniques:
• Epineural suture
• Epi-perineural suture
• Perineural suture
• Group fascicular repair
Nerve rep
a
ir c
a
n be either end-to-end or by using
a
nerve gr
a
ft.

35. Methods of closing nerve gaps
Sometimes, the loss of nerve tissue is so much, that an end-to-end suture cannot be obtained. In such
a situation, the following measures are adopted to gain length and achieve an end-to-end suture:
• Mobilisation of the nerve on both sides of the lesion.
• Relaxation of the nerve by temporarily positioning the joints in a favourable position.
• Alteration of the course of the nerve, e.g. the ulnar nerve may be brought in front of the medial
epicondyle (anterior transposition).
• Stripping the branches from the parent nerve without tearing them.
• Sacri
fi
cing some unimportant branch if it is hampering nerve mobilisation.
Techniques of nerve repair
Nerve rep
a
ir c
a
n be either end-to-end or by using
a
nerve gr
a
ft.

36. b) Nerve grafting:
• When the nerve gap is more than 10 cm or
end-to-end suture is likely to result in tension
at the suture line, nerve grafting may be done.
• In this, an expandable nerve (the sural nerve) is
taken and sutured between two ends of the
original nerve.
•
Techniques of nerve repair
Nerve rep
a
ir c
a
n be either end-to-end or by using
a
nerve gr
a
ft.

37. Reconstructive surgery:
These are operations performed when
there is no hope of the recovery of a nerve,
usually after 18 months of injury.
Operations included in this group are
tendon transfers, arthrodesis and muscle
transfer.
Rarely, an amputation may be justi
fi
ed for
an anaesthetic limb or the one with
causalgia.
Neurolysis:
This term is applied to the operation
where the nerve is freed from
enveloping scar (perineural
fi
brosis).
This is called external neurolysis.
In many cases, the nerve sheath may
be dissected longitudinally to relieve
the pressure from the
fi
brous tissue
within the nerve (intra-neural
fi
brosis). This is called internal
neurolysis.

38. PROGNOSIS
The following f
a
ctors dict
a
te recovery following
a
nerve rep
a
ir:
GOOD PROGNOSIS BAD PROGNOSIS
Younger Age Older age
A primarily motor nerve, like radial nerve, has a better
prognosis than a mixed nerve.
The more the tension at the suture line,the poorer the
prognosis
Neuropraxia
18 months since injury only sensory functions can be
expected.
Early repair The more proximal the injury, the worse the
prognosis.
The more the crushing and infection, the poorer the
prognosis.
Associated conditions: Infection, ischaemia

39.
ந
ன்றி
…
REFERENCE
1. Essential Orthopaedics - 5th edition
2. Schwartz principles of surgery - 11th edition