Peripheral nerve injuries can occur due to stretching, compression, or laceration of nerves outside of the brain and spinal cord. These injuries are commonly caused by trauma or fractures and can result in numbness, weakness, or paralysis depending on the specific nerve affected. Peripheral nerve injuries are often classified by severity and investigated using electromyography and nerve conduction studies. Treatment may involve splinting, rehabilitation, or surgical repair depending on the nature of the injury. Common specific nerve injuries include brachial plexus injuries, median and ulnar nerve injuries, and injuries to the radial, femoral, and sciatic nerves.

1. PERIPHERAL NERVE
INJURY
By: Nabilah binti Abdul Malek

2. OUTLINE Definition
Epidemiology
Mechanism of Injury
Classifications
Approach
Management
Complications + Prognosis
Specific Nerve Injuries

3. DEFINITION OF PERIPHERAL NERVOUS SYSTEM
• The peripheral nervous system refers to
parts of nervous system outside the
brain and spinal cord.
• It is bundles of nerve fibers or axons
conduct information to and from the
CNS.
• Eg: cranial nerves, spinal nerves,
peripheral nerves and neuromuscular
junction.

4. EPIDEMIOLOGY
• Major peripheral nerve injury sustained in
2% of patients with extremity trauma
• 3% of upper extremity and hand injuries,
accounted for nerve injuries
• M = F
• Risk Factors :
 Penetrating Injury
 Displaced Fracture
MECHANISM OF INJURY
• Stretching
 8% elongation --> diminish nerve’s
microcirculation
 15% elongation --> disrupts axons
 eg: suprascapular nerve injury in volleyball
players
• Compression / Crush
 30 mmHg --> increase latency -->
paresthesia
 60 mmHg --> complete conduction block
• Laceration
• sharp transection is better in prognosis than
crush injury

5. 2
1 SEDDONS
SUNDERLANDS
CLASSIFI-
CATIONS

6. APPROACH
• History + Symptoms
• Numbness
• Weakness
• Inability to move
• H/o injection
• U/L Leprosy / DM / Mass
• Signs
• attitude and deformity
• wasting of muscle
• skin (dry, shiny, brittle nails)
• temperature (colder)
• motor exam
• sensory impaired

7. • Investigations
 Electromyography (EMG)
 Nerve conduction velocity (NCV)
 Xray
MANAGEMENT

8. • EMG
• assesses function at the neuromuscular
junction
• often the only objective evidence of a
compressive neuropathy (valuable in workers'
compensation patients with secondary gain
issues)
• characteristic findings
 denervation of muscle
• fibrillations
• positive sharp waves (PSW)
• fasciculations
 neurogenic lesions
• fasciculations
• myokymic potentials
 myopathies
• complex repetitive discharges
• myotonic discharges
• NCV
• assesses large myelinated fibers
• focal compression and demyelination
leads to:
1) increase latencies (slowing) of
NCV
2) distal sensory latency of > 3.2 ms
are abnormal for CTS
3) motor latencies > 4.3 ms are
abnormal for CTS
4) decreased conduction velocities
less specific that latencies
5) velocity of < 52 m/sec is abnormal
6) motor action potential (MAP)
decreases in amplitude
7) sensory nerve action potential
(SNAP) decreases in amplitude

9. TREATMENT
Conservative (1mm/day)
• indications:
 Neuropraxia (1st degree)
 Axonotmesis (2nd degree)
 Gunshot wounds affecting brachial
plexus
(assess extent of recovery over 3
months)
• components:
 active survaillance
 splinting
 rehabilitation
Operative
• Direct muscular neurotization
• Surgical Repair
• Nerve Graft
• Nerve Transfer
• Tendon Transfer

10. Complication
 Neuroma (3% amputees)
• pharm - gabapentin, anti-
depressant, anti-convulsion
• local nerve destruction - phenol @
botulinom injection, cautery
• rehabilitation
• work modification
Prognosis
Better in:
• younger age
• distal injury
• sharp transection / stretched
• early repair

11. SPECIFIC NERVE
INJURIES
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please try to explain your point of view as succinctly as possible.

12. BRACHIAL
PLEXUS

13. AXILLARY NERVE
• course
post cord of brachial plexus (c5,c6)
posteriorly through quadrangular intermuscular
space with posterior circumflex humeral
vessels
deep to deltoid, it divides into anterior and
posterior branch
• supply:
(m) deltoid, teres minor
(s) upper lateral cutaneous nerve of arm
anterior
branch
posterior
branch

14. AXILLARY NERVE
Scenario:
• fracture neck of humerus
• anterior shoulder dislocation
Effect:
• Inability to maintain shoulder abduction (18 -
90’)
• Wasting of deltoid muscle (flat shoulder)
• Small area of numbness over the deltoid
(sergeant's patch sign)

15. MUSCULOCUTANEOUS NERVE
• Course:
lateral cord (C5, C6, C7)
descends lateral to 3rd part of axillary artery
penetrates the coracobrachialis muscle
descends in between biceps and brachialis
at lateral side of biceps tendon it perces the
deep fascia to continue as lateral cutaneous
nerve of forearm
• supply:
m : coracobrachialis, biceps, brachialis
s: lateral cutaneous nerve of arm

16. MUSCULOCUTANEOUS NERVE
• Effect
 Weakness of elbow flexion and forearm
supination.
 Weak or absent biceps tendon reflex.
 Chronic: poor muscle tone, marked wasting
and possibly fasciculation.
 Sensory loss over the lateral and volar
aspect of the forearm.

17. MEDIAN NERVE
• course:
lateral root of lateral cord (c5, c6, c7)
+ medial root of medial cord (c8, t1)
descend lateral to 3rd part of axillary artery
crosses of brachial artery to continue on medial side till reaching
cubital f ossa
enters f orearm through 2 heads of pronator teres
covered by Flexor Digitorum Superficialis (FDS)
at lower part, become superficial
• Supply:
Pronator Teres, Flexor Carpi Radialis, Palmaris Longus, Flexor
Digitorum Superficialis

18. MEDIAN NERVE
enters hand by passing deep to lateral part of
flexor retinaculum
at the distal of retinaculum, it branches to
muscular branch, lateral division and medial
division
supply:
muscular br - all thenar muscles
(APB, FPB, OP)
lateral division - (s) 3 palmar digital branches,
(m) 1st lumbrical
medial division - (s) 2 palmar digitar branches
(m) 2nd lumbrical

19. ANTERIOR INTEROSSEOUS NERVE
Upper part of median nerve gives branch to
AIN
It then descends over the interossesous
membrane accompanied by AIA.
AIN terminates in pronator quadratus
Supply
 Flexor Pollicis Longus
 Flexor Digitorum Profundus (lateral 1/2)
 Pronator Quadratus

20. Nerve Region Branches
Median Nerve
Arm Nil
Forearm
Pronator Teres
Flexor Carpi Radialis
Palmaris Longus
Flexor Digitorum Superficialis
Hand
Thenar muscles, 1st + 2nd
lumbricals
3.5 palmar cutaneous
AIN Forearm
Flexor Pollicis Longus
Flexor Digitorum Profundus
(lateral 1/2)
Pronator Quadratus

23. MEDIAN AND ANTERIOR INTEROSSEOUS NERVES
Location of lesion Motor Deficit
Proximal (above AIN origin)
• Benediction sign
• Impaired wrist pronation and flexion
• Thenar muscle atrophy (chronic)
Distal (affecting AIN) • Impaired OK Sign
Distal (below AIN)
• Loss of thumb abduction, flexion, opposition
• Median claw
• Ape hand
• Palmar cutaneous nerve
Distal (within wrist) Carpal tunnel syndrome
• Phalen’s Test
• Compression’s Test
• Tinel’s Test

24. ULNAR NERVE
• course:
medial cord (C7, C8, T1)
descends medial to 3rd part of axillary artery
pierce the IM septum at medial part of arm to
reach posterior compartment upto medial
epicondyle
enters forearm by 2 heads of FCU
and covered by FCU
lower part of arm, become superficial
enters hand superficial to medial flexor
retinaculum (canal of guyon)
lies lateral to pisiform and hook of hamate
at distal border of retinaculum, divides into
superficial and deep branches
FC
U

25. ULNAR NERVE
• Supply:
Ulnar Nerve
Region
Branches
Forearm Flexor Carpi Ulnaris
Flexor Digitorum Profundus (medial 1/2)
Palmar and dorsal cutaneous branch
Hand Superficial branch:
- palmaris brevis
- 2 palmar digital branches
Deep branch:
- Hypothenar muscles
- All palmar and dorsal interossei
- Adductor pollicis
- 3rd and 4th lumbricals
- Deep head of FPB

26. ULNAR NERVE
Location Deficits
Low Lesion
Numbness ulnar 1 1/2 of fingers
Inability to cross fingers
Inablity to do peace sign
Froments sign +
Ulnar claw
Wartenberg sign
Hypothenar and interossei wasting
High Lesion
Low lesions +
Ulnar paradox
Radial deviation of wrist

27. RADIAL NERVE
• course:
posterior cords (C5, C6, C7, C8, T1)
descends posterior to 3rd part of axillary
artery
passes lower triangular IM spaces
decends through radial groove
pierces the lateral IM septum of distal 3rd of
arm to reach anterior compartment
descend between groove of brachialis and
brachioradialis
terminates in front of lateral epicondyle, and
dividing into superficial (sensory) and deep
terminal branches (PIN)

28. At lower part of forearm, superficial (sensory)
branch deviates backward deep to the tendon
of brachioadialis and peirces the deep fascia
it divides into 5 terminal digital branches
which descend superficial to the extensor
retionaculum
These branches supply:
• dorsum lateral 2/3 hand
• dorsum lateral 3 1/2 fingers

29. POSTERIOR INTEROSSEOUS
NERVE
• Course:
PIN then pierces the supinator to reach the
back. It descends between superficial and
deep group of muscles.
In the lower part of forearm, it becomes very
thin and enters the hand through the 4th
compartment

30. Nerve Region Supply
Radial
Nerve
Arm
(M)
Triceps,
Brachialis
(S)
Lower lateral cutaneous nerve of arm
Posterior cutaneous nerve of forearm
Forearm Brachioradialis
Extensor Carpi Radialis Longus
Anconeus
Hand Dorsum lateral 2/3 hand
Dorsum lateral 3 1/2 fingers
PIN Forearm
Extensor Carpi Radialis Brevis
Extensor Digitorum
Extensor Digiti Minimi
Extensor Carpi Ulnaris
Anconeus
Supinator
Abductor Policis Longus
Extensor Policis Longus
Extensor Policis Brevis
Extensor Indicis

31. Radial Nerve Deficits
Low lesion
(# / dislocation of elbow, affecting PIN)
Finger drop
Inability to:
- extend thumb
- extend MCPJ of hand
High lesion
(shaft of humerus)
Wrist drop
Finger drop
Sensory loss to anatomical snuff
box
very high lesion Extension of elbow joint is
impaired +
Wrist drop +
Finger drop
Sensory loss:
anatomical snuff box
3.5 lateral fingers

32. FEMORAL NERVE
• Course:
L2, L3, L4 posterior division of ventral rami
It emerges from lateral border of psoas major
descend in the groove btwn psoas major and
iliacus
enter thigh by passing deep to midpoint of
inguinal ligament (outside the femoral sheath)
one inch distal to inguinal ligament, it divides
into anterior and posterior divisions

33. • Branches
 In the abdomen : nerve to iliacus
 Below inguinal ligament: nerve to pectineus
 Anterior division :
 Nerve to sartorius
 Intermediate cutaneous nerve of thigh
 Medial cutaneous nerve of thigh
 Posterior division :
 Quadriceps femoris
 Saphenous nerve (medial cut of leg and
dorsum of foot)

34. FEMORAL NERVE
• Scenario:
 injured by gunshot
 pressure of traction during operation
 bleeding into thigh
• Features
 weakness of hip flexion
 paralysis of quadriceps muscle, thus
unable to extend the knee actively
 numbness of anterior and medial aspect
of thigh and medial aspect of leg and
dorsum of foot
 knee reflex is depressed

35. SCIATIC NERVE
• Origin:
L4,5 - S1,2,3
Passes from the pelvis to reach the gluteal
region by passing through the greater sciatic
foramen below piriformis muscle
descends in the middle line of thigh
and dividing into 2 terminal branches
Tibial nerve (L4,5 - S1,2,3)
and common peroneal nerve (L4,5-S1,2)

36. • Supply
 semitendinosus
 semimembranosus
 adductor magnus
 biceps femoris
 Common Peroneal Nerve
 Tibial Nerve

37. • Scenario:
 traumatic hip dislocation (posteriorly)
 pelvic fracture
• Features
 paralysis of hamstring and all below
knee muscles
 absent ankle jerk
 loss of sensation below knee except
medial aspect of leg (saphenous nerve)
 patient walks with foot drop and high
stepping gait

38. Reference
• Orthobullets
• Human Anatomy by Dr Ayman Ahmed Khanfour
• Complete Orthopedics (Y&Z Orthopedics, Jo & Li, Orthopedia)
• Miller’s Review of Orthopedics

39. THANK YOU