Radial Nerve Palsy – Causes, Symptoms, Diagnosis, Treatment

Radial Nerve Palsy from the posterior cord of the brachial plexus and supplies the upper limb. It also supplies the triceps brachii muscle of the arm, the muscles in the posterior compartment of the forearm (also known as the extensors), the wrist joint capsule, and aspects of the dorsal skin of the forearm and hand.

The radial nerve stems from the posterior cord of the brachial plexus and supplies the upper limb. It also supplies the triceps brachii muscle of the arm, the muscles in the posterior compartment of the forearm (also known as the extensors), the wrist joint capsule, and aspects of the dorsal skin of the forearm and hand.

The radial nerve proper innervates

  • Triceps
  • Anconeus
  • Extensor carpi radialis longus (ECRL)
  • Extensor carpi radialis brevis (ECRB)
  • Brachioradialis

The radial nerve divides into a deep (mostly motor) branch, which becomes the posterior interosseous nerve (PIN), and a superficial branch. The PIN innervates

  • Extensor digitorum
  • Supinator muscle
  • Extensor digiti minimi (EDM)
  • Extensor carpi ulnaris (ECU)
  • Abductor pollicis longus (APL)
  • Extensor pollicis longus (EPL)
  • Extensor pollicis brevis (EPB)
  • Extensor indicis proprius (EIP)

Sensory innervation includes

  • Posterior cutaneous nerve (arm and forearm)
  • Superficial branch radial nerve (SBRN)
  • Dorsal digital branch

Causes of Radial Nerve Palsy

Radial nerve injuries can occur after trauma. Common forms of radial nerve injuries occur with the following

  • After fractures of the humerus, especially spiral fracture patterns along with the distal third of the humerus (Holstein-Lewis fracture) with a known associated incidence of radial nerve neuropraxia in the range of 15% to 25%
  • Improper use of crutches
  • Overuse of the arm (secondary to manual labor, chronic overuse, or sport-related participation)
  • Work-related accidents

Radial nerve injuries have distinct presentations and symptoms, depending on the anatomic location and type of injury occurring to the nerve. For example, injuring the radial nerve at the axilla has a different clinical presentation than injuring it at the distal forearm.

Symptoms of Radial Nerve Palsy

Radial nerve palsy symptoms include

  • Weakness or numbness – You may have weakness or numbness from your triceps down to your fingers. You may not be able to make a fist. You may not be able to straighten your elbow or extend your fingers. You may begin to lose muscle in your upper or lower arm and it may look smaller.
  • Wrist drop – This is when your wrist hangs down limply and you cannot lift it.
  • Pinch and grasp problems – You may not be able to bring your thumb and fingers together (pinch) to grasp objects.
  • Numbness from the triceps down to the fingers
  • Problems extending the wrist or fingers
  • Pinching and grasping problems
  • Weakness or inability to control muscles from the triceps down to the fingers
  • Wrist drop – when the wrist hangs limply and the patient cannot lift it
  • Lost ability or discomfort in extending the elbow
  • The lost ability or discomfort bending the hand back at the wrist
  • Numbness
  • Abnormal sensations near the thumb, index and middle fingers
  • Sharp or burning pain
  • Weakness in grip
  • Drooping of the hand also called wrist drop

Diagnosis of Radial Nerve Palsy

History and Physical Exam

  • A patient with radial neuropathy may present holding their affected extremity with the ipsilateral (normal) hand. He or she may complain of decreased or absent sensation on the dorsomedial side of their hand and wrist with an inability to extend their wrist, thumb, and fingers. With the hand supinated, and the extensors aided by gravity, hand function may appear normal. However, when the hand is pronated, the wrist and hand will drop. This is also referred to as “wrist drop.”
  • If damaged at the axilla, there will be a loss of extension of the forearm, hand, and fingers. Thus, this usually presents with a wrist drop on physical examination. There will be a sensory loss in the lateral arm. There will also be a sensory loss in the posterior aspect of the forearm radiating to the radial aspect of the dorsal hand and digits.
  • This is seen commonly with “Saturday night palsy,” and improperly using crutches (crutch palsy). Any condition or clinical situation in which the patient has improperly created pathologic forces and/or compression in the axilla can potentially affect the radial nerve by way of the brachial plexus.

Injuring the radial nerve distal to the elbow joint can occur from

  • Elbow dislocations
  • Elbow fractures
  • Tight casts/compressive wraps
  • Rheumatoid conditions/inflammatory arthritides

The following tests can quickly assess the radial nerve and its motor and sensory functions

  • Motor function: Thumb extension against resistance
  • Sensory function: Two-point discrimination on the dorsum of the thumb

Nevertheless, a thorough physical exam is always required. Radial nerve injuries have distinct signs and symptoms depending on where and how the nerve has been injured.

Special Test

  • Tinel sign – gentle tapping over the course of the superficial branch of the radial nerve resulting in the reproduction of pain and/or paresthesias. This is the most common finding.
  • Dellon test – THis test is performed with active, forceful hyperpronation of the forearm with flexion and ulnar deviation of the wrist, which reproduces symptoms of pain.
  • Finkelstein test – performed by asking the patient to make a fist around the thumb and ulnar deviate the wrist. A positive test is indicative of De Quervain tenosynovitis (tendonitis of the first dorsal compartment). This test may be positive in patients with Wartenberg syndrome as the neuropathy, and first dorsal compartment tenosynovitis may coexist.


  • X-rays – X-rays of the affected extremity at the elbow and wrist should be obtained to rule out any osseous deformity that may cause nerve entrapment, as well as cervical spine radiographs that may reveal sources of radiculopathy or first rib involvement. Finally, a chest x-ray should be obtained to rule out compression of the medial chord by an apical lung or Pancoast tumor, particularly in a patient with a positive history for smoking.
  • Plain radiographs – May be useful during instances where there is a history of trauma, or there is suspicion of a fracture. It can also help to identify cases of osteoarthritis, bony prominences or osteophytes, and the presence of orthopedic hardware that could compress nerves.
  • Ultrasound  – of the nerve at the elbow and wrist can be used to measure the size of the radial nerve compared to controls, as well as to identify a thrombosis of the radial artery that can lead to ulnar nerve symptoms originating in Guyon’s canal.
  • Electrodiagnostic studies – Electromyography and nerve conduction studies help to localize the nerve involved as well as where along the course of the nerve it is affected. Additionally, testing can serve as a baseline for comparison with future studies during the course of treatment. It is important to note that normal electrodiagnostic studies do not rule out disease, and clinical correlation should include the patient’s history and physical examination findings.
  • Magnetic Resonance Imaging (MRI) – Can be useful in the identification of ganglion cysts, synovial or muscular hypertrophy, edema, vascular disease, as well as nerve changes. The cross-sectional area and space available for the nerve can also be measured and compared to accepted normal values.
  • Nerve ultrasonography – The use of nerve ultrasonography has increased recently. It can measure the cross-sectional area and the longitudinal diameter of the nerve. It can also identify compressive lesions. Ultrasound may also evaluate the presence of local edema.  Additionally, ultrasound may help distinguish between different causes of wrist pain that can include tendonitis or osteoarthritis.
  • Serologic studies – There are no blood tests used to specifically support the diagnosis of nerve compression, but the use of these tests may be necessary for medical conditions that can either promote nerve compression or can mimic their symptoms. Some of the most frequently encountered conditions include diabetes and hypothyroidism. The assessment of a patient’s fasting blood glucose, hemoglobin A1c, or thyroid function tests may be helpful in the general management of the patient. Other conditions that could mimic nerve compression include deficiency of vitamin B12 or folate, vasculitides, and fibromyalgia.
  • Electromyography –  is also commonly used in the diagnosis of compression neuropathy with muscle denervation. Compressive neuropathies result in increased distal latency and decreased conduction velocity. Thus in patients with cubital tunnel syndrome, one is likely to identify a slowing of conduction in the ulnar nerve segment crossing the elbow.
  • Both ultrasonic scanning (USS) – and magnetic resonance imaging (MRI) have sensitivity and specificity over 80% in diagnosis. MRI and USS are also helpful to identify other causes of compression, which may not be picked up on plain radiograph films such as soft tissue swelling and lesions such as neuroma, ganglions, aneurysms, etc.
  • Electromyographic and nerve conduction velocity – studies are used to evaluate the ulnar nerve pathology and to rule out other diagnoses.

Electromyograms or nerve conduction studies (EMG/NCS) can help differentiate nerve versus muscle injury, measuring the speed at which the impulses travel along the nerve. EMG/NCS is also utilized for follow-up management in serial observations for the return of nerve function. It is important to note that more than 90% of radial nerve palsies will resolve in 3 to 4 months with observation alone.


Nonoperative Therapy for Radial Nerve Palsy

Initial management is aimed at keeping joints supple and preventing contracture. Patients are instructed to perform frequent passive range of motion (PROM) including stretching the pronator, wrist flexors, and extrinsic finger flexors. Educating patients on the diagnosis and order of muscle return is helpful to manage expectations.

Orthotic Management

  • a. With acute nerve palsy, the arm can be splinted in a long arm orthosis at an elbow flexion of 90 degrees, neutral rotation, and slight wrist extension.
  • b.Functional use is mostly accomplished with a forearm-based dynamic extensor outrigger orthosis. The purpose of the orthosis is to assist with wrist, finger, and thumb extension and release while allowing the patient to conduct a natural grasp reflex. This orthosis can be fabricated as a tenodesis orthosis in which the intact finger flexors create tension to allow finger extension. Another option can be to extend the orthosis to the dorsum of the hand and include the thumb in extension to assist with manipulation. This orthosis helps prevent the adaptive shortening of the digital and wrist flexors while protecting the extensor mechanism from elongation.
  • c.The patient can also use a custom or prefabricated wrist orthosis at 30 to 45 degrees extension to be used at night or during the day to rest the hand from the dynamic outrigger. The wrist orthosis can be used exclusively once assessment demonstrates a manual muscle test (MMT) of ECRB 4/5 and extensor digitorum communis (EDC) 3 +/5 (Figure 8-4). The wrist orthosis is discontinued if MMT ECRB is 4 +/5

Muscle Reeducation and Training

  • A. Perform PROM exercises to diminish forearm pronation tightness, extrinsic flexor tightness, and intrinsic tightness and restore muscle balance.
  • B. When an MMT of at least 3/5 is noted in involved muscles, the patient can add isometric hold exercises to facilitate neuromotor control of the returning muscles. Repetitions of muscle contraction should be limited due to the rapid fatigue of newly reinnervated muscles.
  • C. Patients may need to continue to wear orthoses to support wrist and fingers because of rapid fatigue and to prevent extensor elongation.
  • D.If digital extensors return to MMT 4/5, progress the rehabilitation process by including isotonic strength and endurance training to the entire upper extremity.

Conservative treatment options depend on the severity of the injury and the patient’s symptoms. They include:

  • Bracing or splinting – Your doctor may prescribe a padded brace or splint to wear at night to keep your elbow in a straight position.
  • Immobilization – with proper splints for at least 2 to 4 weeks, or until the symptoms have resolved.
  • Nerve gliding exercises – Some doctors think that exercises to help the ulnar nerve slide through the cubital tunnel at the elbow and the Guyon’s canal at the wrist can improve symptoms. These exercises may also help prevent stiffness in the arm and wrist.
  • Exercises – that strengthen the interosseous muscles and lubricants are recommended. The individual should be taught to exercise each finger and thumb in abduction and adduction motion while the hand is pronated. In addition, the MCP and ICP joints should be exercised and over time the interosseous and lumbrical will gain strength.
  • An elbow pad – This helps with pressure on the joint.
  • Occupational and physical therapy – This will help your arm and hand become stronger and more flexible.
  • Nerve-gliding exercise – Do this to help guide the nerve through the proper “tunnels” in the wrist and elbow.
  • Bracing or Splinting – Immobilizing your arm in a brace for a few weeks or longer can help you to avoid additional damage. Your doctor may also suggest wearing a splint at night to prevent your arm from bending while you sleep.
  • Hand Therapy – Your doctor may recommend hand therapy, which is performed by physical and occupational therapists at NYU Langone. Hand therapy involves strengthening and stretching exercises for your hand as well as your arm and elbow. NYU Langone therapists certified in hand therapy can work with you to develop an exercise plan specific to your needs. Although you may initially visit your therapist several times per week, you can eventually perform the exercises at home


If the injury is severe and pain is intolerable the following medicine can be considered to prescribe


Some radial nerve injuries end up requiring more aggressive management. If the radial nerve is entrapped and symptoms last for several months, surgery is indicated to relieve the pressure on the nerve. This should always be the last option for the patient.

  • Radial nerve anterior transposition – This moves the ulnar nerve so that it doesn’t stretch over the bony parts of the elbow joint.
  • Medial epicondylectomy – This removes the bump on the inside of the elbow joint, which takes the pressure off the ulnar nerve.

Various methods of surgical treatment have been discussed and performed. Some of the well-accepted surgical procedures for the treatment of cubital tunnel syndrome are

  • In-situ decompression; endoscopic decompression; decompression – followed by subsequent subcutaneous transposition, intramuscular transposition, or submuscular transposition and medial epicondylectomy along with in-situ decompression. Studies have shown no benefit of one over the other in terms of clinical outcomes.
  • Surgery is usually in the form of tendon transfers – This addresses issues including the lack of thumb adduction and lateral pinch, the claw deformity of the fingers that impairs object acquisition, and the loss of ring and small finger flexion.
  • The extensor carpi radialis brevis or the flexor digitorum superficialis – is the most commonly used transfers to restore thumb adduction. The brachioradialis can be used if the extensor carpi radialis brevis is required for an intrinsic reconstruction of the fingers.
  • To correct the claw deformity of the fingers – include static procedures or dynamic transfers. A dynamic transfer uses the flexor digitorum superficialis, extensor carpi radialis longus, extensor carpi radialis brevis, or flexor carpi radialis as a donor’s muscle.
  • To restore the ring and small finger extrinsic muscle function, a transfer of flexor digitorum profundus ring and small to flexor digitorum profundus middle is performed.

Nerve transfer

  • in the report by Özkan T, et al., prospective study was conducted to evaluate patient outcomes following sensory nerve transfer; 20 patients with irreparable ulnar or median nerve lesions underwent the procedure; 18 of 20 patients attended a sensory re-education program after surgery; 2-point discrimination of less than 10 mm was achieved in 15 of 25 hands; 18 of 20 patients reported that the function of their hands improved after the procedure good or excellent results were associated with immediate transfer of the nerve, young age, and patients’attendance to the sensory re-education program after surgery;

Nerve conduits

  • may be indicated when a tension-free repair is not possible; may only allow 2 cm of nerve regeneration

Repair Based on Level of Injury nerve repair in the hand

more proximal lacerations have worse outcomes than distal lacerations; at the wrist level, one-half of patients will have good result; exam findings for nerve injury:

  • loss of two-point discrimination dryness over the affected dermatomes (loss of sweat gland innervation)

Digital Nerves

digital nerves may contain one to three fascicles;

  • best managed w/ epineural nerve repair use 9-0 or 10-0 prolene; patients may expect functional/protective sensation, but in the majority of patients, the normal sensation will not be obtained; generally, nerve repair is not indicated distal to the DIP;

Median And Ulnar Nerves At The Wrist

  • low median lesions (median nerve injuries at the wrist) low ulnar lesion in these injuries, wrist flexion significantly reduces tension at the nerve repair site; elbow flexion and nerve transposition will have no effect on tension at the repair site; group fascicular nerve repair may be indicated for nerve lacerations at the wrist level;

Ulnar Nerve Lacerations At The Elbow

  • tension at nerve repair site may be reduced by both nerve transposition and elbow flexion, but the magnitude of this effect remains unclear;

Nerve Repair Techniques

  • note that whatever repair technique is used, the repair should be strong to withstand the need for early ROM should it be necessary (as in concomitant tendon injury); epineural nerve repair involves repair of the epineural tissue – the loose connective tissue which surrounds the fascicles; group fascicular nerve repair: involves repair of the internal epineural tissue which surrounds the group fascicles; disadvantages include the increased need for nerve manipulation in order to align fascicles and the possibility of anastomosing incorrect fascicles (which will lead to a poor result); management of tension at nerve site repair:
  • indicated for nerve defects more than 1 cm (or in any case where the nerve would be repaired under tension);
    sural nerve graft; note that the patient must be in the lateral position for nerve harvest, which may interfere with the positioning

Physical Therapy

Exercises For Radial Nerve Entrapment At The Elbow

Exercise 1

  • Start with your arm extended straight and your palm up.
  • Curl your fingers inward.
  • Bend your elbow, bringing your curled fist up toward your shoulder.
  • Return to your starting position.
  • Repeat the exercise 3 to 5 times, 2 to 3 times a day.

Exercise 2

  • Extend your arm out to the side at shoulder level, with your palm facing the floor.
  • Flex your hand upward, pulling your fingers toward the ceiling
  • Bend your elbow, bringing your hand toward your shoulders.
  • Repeat the exercise slowly 5 times.

Exercises For Radial Nerve Entrapment At The Wrist

Exercise 1

  • Stand straight with your arms at your side.
  • Raise the affected arm and rest your palm on your forehead.
  • Hold your hand there for a few seconds and then bring your hand down slowly.
  • Repeat the exercise a few times a day, gradually increasing the number of repetitions you do in each session.

Exercise 2

  • Stand or sit tall with your arm held straight out to the front of you and your palm facing up.
  • Curl your wrist and fingers toward your body.
  • Bend your hand away from the body to gently stretch your wrist.
  • Bend your elbow and raise your hand upward.

Post-Operative Care

After surgery, your surgeon will give you guidelines to follow depending on the type of repair performed and the surgeon’s preference. Common post-operative guidelines include:

  • A bulky dressing with a plaster splint is usually applied following surgery for 10-14 days.
  • Elevating the arm above the heart level and moving the fingers are important to prevent swelling.
  • The arm dressing is removed after 10-14 days for removal of the sutures.
  • Elbow immobilization for 3 weeks after surgery is usually indicated, longer depending on the repair performed.
  • Ice packs are applied to the surgical area to reduce swelling. Ice should be applied over a towel to the affected area for 20 minutes every hour. Keep the surgical incision clean and dry. Cover the area with plastic wrap when bathing or showering.
  • Occupational Therapy will be ordered a few weeks after surgery for strengthening and stretching exercises to maximize the use of the hand and forearm


  • Repeat the exercise a few times a day, gradually increasing the number of repetitions you do in each session.
  • The impairment-based approach can be used to address deficits in strength, ROM, and the attainment of functional goals
  • The source of the pain should be treated in conjunction with the impairments.
  • Following treatment, reassess the functional task that produced pain to determine effective treatment outcome
  • Administer a home exercise program that aims to treat the same impairments and function tasks In a study conducted by Svernlov and colleagues, three treatments were compared for individuals with cubital tunnel syndrome.[rx] All three groups had positive outcomes, with the control group improving just as much as the intervention groups.[rx]
  • Splint group protocol   – An elbow brace was worn every night for a period of three months and the brace prevented elbow flexion beyond 45 degrees.
  • Nerve gliding protoco– Patients were instructed to complete nerve gliding exercises two times per day in six different positions and hold them for 30 seconds for three repetitions with a 1-minute break in between each repetition. Patients were instructed to complete these exercises until the next visit, which occurred 1-2 weeks later. The frequency of the exercises was increased to three times per day, holding the exercise for one minute each day for a period of three months if there were no symptoms at the next visit.
  • Control group protocol – The control group only received education According to a case report by Coppieters and colleagues, joint mobilizations of the elbow, thoracic spine and rib thrust manipulations, and ulnar nerve sliding/tension techniques for six sessions were associated with improvements of decreased elbow pain and considerable improvement scores on a neck questionnaire up to a ten-month follow-up.[rx] The patient reported a history of symptoms for two months prior to starting physical therapy.[rx] 


Many patients with radial nerve palsy will see complete recovery or symptom relief after the treatment. In some cases, complications may occur, including:

  • Partial or complete loss of feeling in the hand – If the radial nerve doesn’t heal completely, numbness may be permanent.
  • Partial or complete loss of wrist or hand movement – If the radial nerve doesn’t heal completely, weakness may be permanent.
  • Mild-to-severe deformities of the hand – Ongoing radial nerve problems can cause joint and muscle stiffening or muscle atrophy.
  • Recurrent or unnoticed injuries to the wrist or hand – If the wrist or hand are numb, a person may not notice an injury.


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