This document provides an overview of peripheral nerve structure and common sites of injury. It discusses the different types of neurons that make up peripheral nerves, including motor, sensory and sympathetic neurons. Common sites where peripheral nerves can be injured include the intervertebral foramina, brachial plexus and lumbosacral plexus. Mechanisms of nerve injury include compression, laceration, stretch and radiation. The document also outlines guidelines for managing nerve injuries in the acute, recovery and chronic phases.

1. Dr. Maria Idrees; PT

2. Review of Peripheral
Nerve Structure
Nerve Structure
 Peripheral nerves contain a mix of motor, sensory, and
sympathetic neurons.
■ Alpha motor neurons (somatic efferent fibers): cell bodies located
in anterior column of spinal cord; innervate skeletal muscles
■ Gamma motor neurons (efferent fibers): cell bodies located in
lateral columns of spinal cord; innervate intrafusal muscle fibers
of the muscle spindle
■ Sensory neurons (somatic afferent fibers): cell bodies located in
the dorsal root ganglia; innervate sensory receptors
■ Sympathetic neurons (visceral afferent fibers): cell bodies located
in sympathetic ganglia; innervate sweat glands, blood vessels,
viscera, and glands

4. Mobility Characteristics of the
Nervous System
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5. Common Sites of Injury to Peripheral
Nerves
 Anywhere along the pathway from the nerve roots to
their termination in the tissues of the trunk and
extremities.
 Inter vertebral foramen
 Symptoms and signs of nerve impairments are sensory
changes or loss and motor weakness in the distribution
of the involved nerve fibers

6. Nerve Roots
 Nerve roots emerge from the spinal canal and traverse the
foramina of the spine, where they can become impinged as
a result of various pathologies of the spine that reduce the
space in the foramina, such as degenerative disc disease
(DDD), degenerative joint disease (DJD), disc lesions, and
spondylolisthesis.
 With reduced spinal canal or foraminal space (stenosis),
extension, side bending, or rotation to the side of the
stenosis further decreases the space where the nerve root
courses and may cause or perpetuate symptoms
 Nerve roots of the upper quarter include C5 through T1 and
those of the lower quarter L1 through S3.

8. Brachial Plexus

9. Sites of compression

10. Upper plexus injuries (C5, 6): The mechanism involves
shoulder depression and lateral flexion of the neck to the
opposite side. There is loss of abduction and lateral
rotation of the shoulder and weakness in elbow flexion and
forearm supination (waiter’s tip position). Erb’s palsy
occurs with birth injuries when the shoulder is stretched
downward.
 Middle plexus injuries (C7): Rarely seen alone.
 Lower plexus injuries (C8, T1): Usually due to
compression by a cervical rib or stretching the arm
overhead. Klumpke’s paralysis (paralysis of the intrinsics of
the hand) occurs in birth injuries when the baby presents
with its arm overhead.
 Complete or total injury of the plexus: Erb-Klumpke’s
paralysis (Horner’s syndrome)

12. Myotomes

15. Lumbosacral Plexus

18. Mechanisms of Nerve Injury
■ Compression (sustained pressure applied externally, such
as tourniquet, or internally, such as from bone, tumor, or
soft tissue impingement resulting in mechanical or
ischemic injury).
■ Laceration (knife, gunshot, surgical complication, injection
injury).
■ Stretch (excessive tension, tearing from traction forces).
■ Radiation.
■ Electricity (lightening strike, electrical malfunction).
 Intraneural
 Extraneural

20. Excellent regenerative potential: radial,
musculocutaneous, and femoral nerves
Moderate regenerative potential: median, ulnar, and
tibial nerves
Poor regenerative potential: peroneal nerve

21. Outcomes of Nerve Regeneration
 Five possible outcomes of nerve regeneration.
1. Exact reinnervation of its native target organ with
return
 of function
2. Exact reinnervation of its native target organ but no
return
 of function due to degeneration of the end organ
3. Wrong receptor reinnervated in the proper territory;
therefore,
 improper input
4. Receptor reinnervation in wrong territory causing
false
 localization of input
5. No connection with an end organ

22. Management Guidelines:
Recovery from Nerve Injury
Acute Phase
 Movement
 Splinting or bracing
 Patient education
Recovery Phase
 Motor retraining
 Desensitization.
 Patient education
Chronic Phase
 Compensatory function

23. Suggestions for graded modalities and procedures for
desensitizing:
■ Use multiple types of textures or contact for sensory stimulation,
such as cotton, rough material, sandpaper of various grades, and
Velcro. The textures can be wrapped around dowel rods for
finger manipulation or to stroke along the skin.
■ Place contact particles, such as cotton balls, beans, macaroni,
sand, or other material, with various degrees of roughness in
tubs or cans, so the patient can run the involved hand or foot
through the material. Have the patient begin by manipulating or
placing the extremity in the least irritating texture for 10
minutes. As tolerance improves, progress to the next texture of
slightly more irritating but tolerable stimulus. Maximum
progress occurs when the most irritating texture is tolerated.
■ Use vibration. Pattern of recovery after nerve injury is pain
(hypersensitivity), perception of slow vibration (30 cps), moving
touch, constant touch, rapid vibration (256 cps), and awareness
from proximal to distal.

24. Suggestions for retraining the brain to recognize a
stimulus
■ Begin by using a moving touch stimulus, such as the eraser
end of a pencil, and stroke over the area. The patient first
watches, then closes his or her eyes, and tries to identify
where touch occurred.
■ Progress from stroking to using constant touch.
■ When the patient is able to localize constant touch,
progress to identification of familiar objects of various
sizes, shapes, and textures.
■ For the hand, use familiar household and personal care
objects, such as keys, eating utensils, blocks, toothbrush,
and safety pins.
■ For the feet, have the patient walk on various surfaces, such
as grass, sand, wood, pebbles, and uneven surfaces.

25. Neural Testing and Mobilization
Techniques for the Upper Quadrant
 Median Nerve
 Radial Nerve
 Ulner Nerve

26. Neural Testing and Mobilization
Techniques for the Lower Quadrant
 Sciatica Nerve
 Slump sitting
 Femoral Nerve