1. Peripheral Nerve Injuries- Radial

2. Radial Nerve Largest branch of the brachial plexus;
Extends down the humerus to the lateral epicondyle 
where it divides:
- one branch that goes to the skin on the back of the hand
- another that goes to the underlying extensor muscles
Medial, lateral, and long heads of the triceps brachii.
All 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin.
It originates from the brachial plexus, carrying fibers from the ventral roots of spinal nerves C5, C6, C7, C8 & T1.

4. Aetiology
Radial neuropathy occurs when there is damage to the radial nerve, which travels down the arm and controls movement of the triceps muscle at the back of the upper arm.
It also controls the ability to bend the wrist backward and helps with the movement and sensation of the wrist and hand.
Mononeuropathy means a single nerve is damaged.
With mononeuropathy, usually the nerve damage is caused locally. However, body-wide disorders may damage just one nerve.

5. Aetiology Improper use of crutches Broken upper arm bone
Long-term or repeated constriction of the wrist (for example, from wearing a tight watch strap)
Pressure caused by hanging the arm over the back of a chair (for example, falling asleep in that position)
Pressure to the upper arm from arm positions during sleep or coma
Pinching of the nerve during deep sleep, such as when a person is intoxicated
Long-term pressure on the nerve, usually caused by swelling or injury of nearby body structures
Lead poisoning
In some cases, no cause can be found.
If other nerves are also affected, the health care provider should look for a medical problem that can affect nerves. Medical conditions such as diabetes and kidney disease can damage nerves

6. Pathophysiology
Most nerve injuries seen by physical therapists result from compression.
Excessive acute compression can involve compromise to the blood supply (ischemia) of the neural tissue.
Compression can also result from entrapment either:
*chronic compartment compression
*mechanical irritation with an ensuing inflammatory reaction and subsequent fibrosis.
An example of an acute compression nerve injury is a radial nerve palsy at the spiral groove (Saturday night palsy).

7. Seddon has classified nerve injuries into 3 categories:
Pathophysiology
Nerve injury secondary to compression or traction depends on intensity and duration.
Seddon has classified nerve injuries into 3 categories:
1st Neuropraxia- is a transient episode of motor paralysis with little or no sensory or autonomic dysfunction.
No disruption of the nerve or its sheath occurs. With removal of the compressing force, recovery should be complete.

8. Sunderland has classified nerve injury into 5 categories:
Pathophysiology
2nd axonotmesis- more severe + disruption of the axon but with maintenance of the Schwann sheath.
Motor, sensory, and autonomic paralysis results.
3rd Neurotmesis - most serious injury.
The nerve and its sheath are disrupted.
Sunderland has classified nerve injury into 5 categories:
The first is similar to neuropraxia.
The second is similar to axonotmesis.
The third, fourth, and fifth degrees correspond to varying degrees of neurotmesis.

9. Clinical Presentation
Radial nerve palsy
Radial nerve palsy in the middle third of the arm is characterized by
palsy or paralysis of
all extensors of the wrist and digits, forearm supinators.
Very proximal lesions also may affect the triceps.
Numbness occurs on the dorsoradial aspect of the hand and the dorsal aspect of the radial 3 ½ digits.
Sensation over the distal and lateral forearm is supplied by the lateral antebrachial cutaneous nerve and therefore is preserved.

10. Clinical Presentation
Radial tunnel syndrome
Pain over the anterolateral proximal forearm in the region of the radial neck.
Often appears in individuals whose work requires repetitive elbow extension or forearm rotation.
The maximum tenderness is located 4 fingerbreadths distal to the lateral epicondyle, as compared with lateral epicondylitis, in which maximum tenderness is usually directly over the epicondyle.
In addition, resisted active supination and extension of the long finger cause pain.
# Weakness and numbness usually are not demonstrated.

11. Clinical Presentation
Posterior interosseous nerve syndrome
Patients present with weakness or paralysis of the wrist and digital extensors.
Pain may be present, but it usually is not a primary symptom.
Attempts at active wrist extension often result in weak dorsoradial deviation due to preservation of the radial wrist extensors
Patients do not have a sensory deficit.
Rarely, compression of the posterior interosseous nerve may occur after bifurcation into medial and lateral branches.

12. Clinical Presentation
Wartenberg syndrome
Patients complain of pain over the distal radial forearm associated with paresthesias over the dorsal radial hand.
Patients frequently report symptom magnification with wrist movement or when tightly pinching the thumb and index digit.
These individuals demonstrate a positive Tinel sign over the RSN and local tenderness.
Hyperpronation of the forearm can cause a positive Tinel sign.
A high percentage of these patients reveal physical examination findings consistent with de Quervain tenosynovitis.

13. Symptoms Abnormal sensations Hand or forearm ("back" of the hand)
"Thumb side" (radial surface) of the hand
Fingers nearest to the thumb (2nd and 3rd fingers)
Difficulty straightening the arm at the elbow
Difficulty bending the hand back at the wrist, or even holding the hand
Numbness, decreased sensation, tingling, or burning sensation
Pain

14. Medical Management pain medication
anti-seizure medications or tricyclic anti-depressants (prescribed to treat pain)
steroid injections
anesthetic creams or patches
braces or splints
physical therapy to help build and maintain muscle strength
massage
acupuncture—inserting thin needles into various pressure points throughout the body.
According to the Mayo Clinic, this alternative method may reduce symptoms in the majority of people with radial neuropathy. However, long-term treatment is required

15. Medical Management
Transcutaneous electrical nerve stimulation (TENS) to treat nerve damage.
This ongoing therapy involves placing several adhesive electrodes on the skin near the affected area. A gentle electric current is delivered through the electrodes at varying speeds.
Surgery
Most people with a radial nerve injury will recover within three months of treatment.
IF NOT
Surgery to relieve pressure on the nerve may be necessary if the nerve is entrapped or there are masses on the nerve. If there is a loss of sensation or movement, or symptoms do not improve, surgery may also be necessary.
This type of surgery will repair any damage to the nerve.
After surgery, a brace or splint will be necessary to allow the injury heal.

16. Medical Management
Your doctor will then refer you to a physical therapist for rehabilitation to restore range of motion and strength.
Physical therapy is started in the early stages after nerve injury to maintain passive range of motion in the affected joints and to maintain muscle strength in the unaffected muscles.

17. Medical Management
A thorough neurological history and examination are required.
The following lists the muscles supplied by the radial nerve and how to test each:
C7, C8: triceps - ask the patient to extend the elbow against resistance.
C5, C6: brachioradialis - ask the patient to flex the elbow with the forearm half way between pronation and supination.
C6, C7: extensor carpi radialis longus - ask the patient to extend the wrist to the radial side with the fingers extended..
C7, C8: extensor carpi ulnaris - ask the patient to extend the wrist to the ulnar side.
C7, C8: abductor pollicis longus - ask the patient to abduct the thumb at 90° to the palm.
C7, C8: extensor pollicis brevis - ask the patient to extend the thumb at the MCP joint.

18. Medical Management
Therapy involves patient education and protection of the joints,
Including the surrounding ligaments and tendons, from further stress.
Splints, slings, or both may be used in these cases.
For example, a radial nerve injury results in a loss of wrist and finger extension, a wrist drop.
A wrist-resting splint may be used to support the hand in a neutral wrist position and place the hand in a more functional position.

19. Medical Management
ROM exercises must be specifically tailored to the injury (eg, severity, timing).
Passive ROM may be contraindicated immediately after suture nerve repair because of the potential for excessive traction forces across the surgical site.
Early passive ROM of an extremity is safe to perform on a nerve injury in continuity.
Positioning Correct positioning of a limb, the head, or the trunk can relieve symptoms of an injured peripheral nerve.
Includes proper standing, sitting, and sleeping postures; proper body mechanics; and ergonomically correct workstations.
For example, passive lumbar extension positioning and exercise can shift the migration of the nucleus pulpous anteriorly to relieve pressure on pain sensitive posterior structures (eg, an inflamed lumbosacral nerve root).

20. References http://www.thefreedictionary.com/radial+nerve
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