Radial nerve dysfunction: MedlinePlus Medical Encyclopedia An illness in the whole body that damages a single nerve Direct injury to the nerve Long-term pressure on the nerve Pressure on the nerve caused by swelling or injury of nearby body structures. 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. Ability to bend the wrist and fingers backward. Movement and sensation of the wrist and hand. When damage destroys the nerve covering ( myelin sheath ) or part of the nerve itself, nerve signaling is slowed or prevented. Damage to the radial nerve can be caused by: Broken arm bone and other injury Diabetes Long-term or repeated constriction of the wrist (for example, from wearing a tight watch strap) Long-term pressure on the nerve, usually caused by swelling or injury of nearby body structures Pressure to the upper arm from arm positions during sleep or coma In some cases, no cause can be found.

Symptoms Symptoms may include any of the following: Abnormal sensations in the back and thumb side of the hand, or in the thumb, 2nd, and 3rd fingers Weakness, loss of coordination of the fingers Problem straightening the arm at the elbow Problem bending the hand back at the wrist, or holding the hand Pain, numbness , decreased sensation, tingling, or burning sensation in the areas controlled by the nerve Exams and Tests The health care provider will examine you and ask about your symptoms and medical history. You may be asked what you were doing before the symptoms started. Tests that may be needed include: Blood tests Imaging tests to view the nerve and nearby structures Electromyography ( EMG ) to check the health of the radial nerve and the muscles it controls Nerve biopsy to examine a piece of nerve tissue (rarely needed) Nerve conduction tests to check how fast nerve signals travel Treatment The goal of treatment is to allow you to use the hand and arm as much as possible. Your provider will find and treat the cause, if possible. Sometimes, no treatment is needed and you will get better on your own.

If medicines are needed, they may include: Over-the-counter or prescription pain medicines Corticosteroid injections around the nerve to reduce swelling and pressure Your provider will likely suggest self-care measures. These may include: A supportive splint at either the wrist or elbow to help prevent further injury and relieve the symptoms. You may need to wear it all day and night, or only at night. An elbow pad of the radial nerve is injured at the elbow. Also, avoid bumping or leaning on the elbow. Physical therapy exercises to help maintain muscle strength in the arm. Occupational therapy or counseling to suggest changes in the workplace may be needed. Surgery to relieve pressure on the nerve may help if the symptoms get worse, or if there is proof that part of the nerve is wasting away. Outlook (Prognosis) If the cause of the nerve dysfunction can be found and successfully treated, there is a good chance that you will fully recover. In some cases, there may be partial or complete loss of movement or sensation.

Possible Complications Mild to severe deformity of the hand Partial or complete loss of feeling in the hand Partial or complete loss of wrist or hand movement Recurrent or unnoticed injury to the hand When to Contact a Medical Professional Call your provider if you have an arm injury and develop numbness, tingling, pain, or weakness down the back of the arm and the thumb and your first 2 fingers. Prevention Avoid prolonged pressure on the upper arm. Alternative Names Neuropathy - radial nerve; Radial nerve palsy; Mononeuropathy Images Radial nerve dysfunction References Katirji B. Disorders of peripheral nerves. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; 2016:chap 107. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 420. Wolfe VM, Rosenwasser MP, Tang P.

Entrapment neuropathies of the arm, elbow, and forearm. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic Sports Medicine: Principles and Practice. 4th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 67. Read More Home Home Key Points: • Assess radial innervated muscles; check for posterior interosseous nerve branch versus radial nerve proper function: • Branches of the radial nerve provide elbow extension, occasional elbow flexion (variably through the brachioradialis muscle as well as a branch to the brachialis muscle), supination of the forearm (although the biceps muscle innervated by musculocutaneous nerve is the major supinator) and wrist/finger/thumb extension. • The posterior interosseous branch of the ulnar nerve specifically provides innervation for the supinator and wrist/finger/thumb extensors. • Sensory exam includes testing the dorsal aspect of the arm and radial sided fingers. • Originates from roots: C5-T1. EXAMINATION • Physical examination of the radial nerve includes both motor and sensory examination.

• Radial nerve function is particularly important in that it contributes to the following radial-nerve-only innervated motor functions: elbow, wrist, finger, and thumb extension. • The radial nerve sensory component, in particular the superficial radial sensory nerve (or radial sensory branch) is notable for its tendency to be a ‘bad actor’ with significant neuropathic pain resulting from even minor injury. Detailed Examination Links: Radial Sensory Nerve (Sensory Branch of the Radial nerve) Summarized Examination: • The three heads of the triceps muscle are quickly tested by assessing resisted elbow extension. Patients with radial nerve dysfunction and intact elbow flexors can flex the elbow and allow gravity to produce the illusion of elbow extension if they are in an upright position so it is critical to assess triceps function by assessing resistance or with gravity eliminated. • Wrist extension is quickly assessed by resistive activities; this assesses the function of extensor carpi radialis brevis, longus and extensor carpi ulnaris.

• The finger extensors should be assessed by checking for extension at the metacarpal phalangeal joint—this is because the ulnar and median innervated intrinsic musculature contributes to interphalangeal joint extension. Retropulsion of the thumb is a quick test for extensor pollicis longus function • The sensory examination involves testing sensation over the dorsoradial aspect of the wrist and hand innervated by the radial sensory nerve. • Patients with a complete radial nerve palsy have a complete wrist drop whereas patients with a posterior interosseous nerve palsy can still radially extend their wrist (via extensor radialis brevis/longus). Pathological Findings: • In patients with isolated radial nerve injury, the most debilitating loss of function is often loss of power grip, because even with intact finger flexion, without the ability to position the wrist in extension, the flexors are suboptimally positioned and powerful grasp is lost. • Isolated injury to the radial sensory nerve is problematic because this nerve is a ‘bad actor’.

Iatrogenic injury in the course of routine procedures such as ganglionectomy and DeQuervain’s (first extensor tendon compartment release) should be avoided through the use of tourniquet control and meticulous dissection intraoperatively. Differentiating injury to the radial sensory nerve branches versus the lateral antebrachial cutaneous nerve can be challenging –see Superficial Branch of Radial Nerve (SBR)/Radial Sensory Nerve (RSN) page for further details. • Known sites of radial nerve compression or entrapment: • Arm: compression in the arm is rare but can occur within the triceps muscle itself or in the upper arm where it courses the lateral intermuscular septum. • Elbow/Proximal Forearm: this is referred to as radial tunnel syndrome the radial tunnel is a region that begins just distal to the takeoff of the branches to the brachioradialis, extensor carpi radialis longus and (usually) brevis where the nerve is at the level of the lateral humeral epicondyle.

It continues under the extensor carpi radialis brevis and on top of the radial capitellum and extends distally to the arcade of Frohse and supinator muscle. The structures that can cause compression include fibrous bands, radial recurrent vessels (leash of Henry), tendinous origin of the extensor carpi radialis brevis, and the arcade of Frohse (which is the tendinous leading edge of the superficial head of the supinator). • Proximal Forearm: the posterior interosseous nerve can be entrapped at the arcade of Froshse and the supinator muscle; radial recurrent vessels (leash of Henry) may also contribute to compressive forces. • Forearm: the radial sensory nerve can be entrapped at the level of the forearm (by the brachioradialis and extensor carpi radialis longus muscles between which it passes) and wrist (by external compression such as a tight wrist watch band). Clinical Relevance: • Loss of radial nerve function is seen in both open and closed arm level injuries such as humeral fractures. Reinnervation of the critical functions, wrist and finger extension, is important to restoring normal upper extremity function.

Without wrist extension, patients have diminished ability to grip and hold objects. Without finger and thumb extension, patients have difficulty in opening the hand to grasp larger objects and do activities such as typing—do note, that the ulnar innervated intrinsic hand musculature provides some finger extension as well. • In radial nerve injury patterns distal to the triceps branch takeoff, when the denervation time permits (3 to 6 months or less is ideal), wrist and digit extensor function can be restored through use of nerve transfers from expendable branches of the median nerve. Tendon transfers may also be done but do not provide independent finger/thumb extension as the nerve transfer procedure can. In chronic injuries, tendon transfers are routinely used and quite effective. • The nerves to the supinator and the extensor carpi radialis brevis in patients with normal radial nerve function are expendable and can be used for nerve transfer procedures (such as to the median nerve). Relevant Anatomy Hand and Wrist Injuries: Part I. Nonemergent Evaluation - American Family Physician Hand and Wrist Injuries: Part I. Nonemergent Evaluation JAMES M.

DANIELS II, M.D., M.P.H., Southern Illinois University School of Medicine, Quincy, Illinois ELVIN G. ZOOK, M.D., Southern Illinois University School of Medicine, Springfield, Illinois JAMES M. LYNCH, M.D., Florida Southern College, Lakeland, Florida Am Fam Physician. 2004 Apr 15;69(8):1941-1948. References Diagnosis of upper extremity injuries depends on knowledge of basic anatomy and biomechanics of the hand and wrist. The wrist is composed of two rows of carpal bones. Flexor and extensor tendons cross the wrist to allow function of the hand and digits. The ulnar, median, and radial nerves provide innervation of the hand and wrist. A systematic primary and secondary examination of the hand and wrist includes assessment of active and passive range of motion of the wrist and digits, and dynamic stability testing. The most commonly fractured bone of the wrist is the scaphoid, and the most common ligamentous instability involves the scaphoid and lunate.

Whether a physician is working in a rural clinic or an urban academic center, or is attending a high school football game, acute injuries of the hand and wrist will be encountered. Patients may not appreciate the severity of these injuries and are as likely to present in a clinic as in the emergency department. Timely diagnosis and treatment of upper extremity injuries are of paramount importance. Failure to diagnose, manage, and rehabilitate upper extremity injuries has the potential to result in permanent disability. 1 Part one of this two-part article reviews an anatomic-based examination of the hand and wrist, allowing the physician to quickly evaluate a patient in a nonemergent setting. Part two 2 focuses on the emergent evaluation of hand and wrist injuries. The bones of the wrist. FIGURE 1. The bones of the wrist. Anatomy References Many injuries of the hand and wrist are obvious, but subtle injuries can be missed without a systematic primary and secondary examination. There are eight carpal bones in the wrist, five metacarpals, and 14 nonsesamoid bones that comprise the phalanges. These 27 bones act dynamically to allow oppositional grip.

3 The proximal row of carpal bones includes the scaphoid (i.e., carpal navicular bone), lunate, triquetrum, and pisiform, which are closely approximated to the distal radius ( Figure 1 ). The triangular fibrocartilage complex, an articular disk located between the proximal row of carpals and the ulna, completes the concave surface on which the carpals move ( Figure 2 ). The distal row of carpals includes the hamate, capitate, trapezium, and trapezoid, which are closely approximated to the metacarpals. The scaphoid links the two rows of carpals. Each digit has two neurovascular bundles near the palmar aspect of the finger—one located radially and the other ulnarly. The neurovascular bundle includes the digital artery, vein, and nerve. 4 The tendons of the finger. FIGURE 3. The tendons of the finger. Each phalanx has a superficial flexor tendon that inserts at the base of the middle phalanx and a profundus flexor tendon that inserts at the base of the distal phalanx.

Consequently, injuries of the flexor tendons are more complicated to evaluate and repair than injuries of the extensor tendons. The extrinsic extensor tendon attaches to the base of the dorsum of the middle phalanx, and bands from the intrinsic hand muscles attach to the distal phalanx. The tendons are connected by fibers that form a hood over the proximal interphalangeal (IP) joint 6 ( Figure 3 ). In general, the radial nerve accounts for wrist and finger extension, the ulnar nerve provides power grip, the median nerve allows for fine control of the pincer grip, and the median and ulnar nerves supply sensation to the palmar surface. However, to truly place the hand in a functioning position, the entire upper extremity must be involved. The ulnar nerve enters the hand alongside the ulnar artery through Guyon's canal, located between the pisiform and the hook of the hamate and covered by the pisohamate ligament ( Figure 4 ). The ulnar nerve supplies the intrinsic muscles of the hand as well as the extrinsic muscles for flexion of the fourth and fifth fingers to provide power grip.

The ulnar nerve also innervates the adductor pollicis and first dorsal interosseous muscles, which allow pinch. The median nerve passes into the hand via the carpal tunnel of the volar aspect of the wrist. The median nerve supplies the thenar compartment, providing opposition and circumduction for fine control. The radial nerve extends the fingers to enhance grasp with the ulnar nerve. Parascaphoid inflammation, radiocarpal instability, midcarpal instability IP = interphalangeal. A patient's inability to assume the “safe hand” position ( Figure 5 ) may suggest a tendon or nerve disruption. 7 If the hand is immobilized in the safe hand position, extension contractures of the metacarpophalangeal (MCP) joint and flexion contractures of the IP joints can be avoided. In normal anatomic position, the thumb is slightly abducted, the MCP joint is at 45 to 70 degrees, and each of the IP joints is slightly flexed at 10 degrees. Physicians should be alerted to the possibility of tendon disruption if any of the fingers are not maintained in the position 8 ( Figure 6 ).

As the hand is closed, fingers should point toward the base of the scaphoid ( Figure 7 ). The distal nail tips should align when the fingers are partially flexed. Subtle skin changes can alert the physician to possible nerve injury. The hand normally has moisture on it; absence of moisture on the distal phalanx may indicate a digital nerve injury. The vascular status of the finger is evaluated by blanching the fingertip; capillaries should refill within two seconds. Sensory nerve function of the digits can be evaluated with two-point discrimination using a paper clip or blunt calipers. The patient should be able to distinguish two points about 5 mm apart. 3 Normal anatomic position of the hand (the “safe hand” position). SECONDARY EXAMINATION The secondary survey should include tests of the superficialis and profundus flexor tendon of each finger. 1 With practice, each of the flexor tendons of the fingers can be evaluated. Each digit should flex independently. The patient should be able to actively flex the distal IP joint, indicating an intact profundus flexor tendon. The superficialis tendon is evaluated by having the patient flex the proximal joint of the finger while the remaining fingers are extended.

If there is any question of tendon disruption, a simple test can be performed. In this test, the physician grasps the patient's forearm approximately 6 to 7 cm from the proximal palmar crease of the wrist and squeezes the forearm. 9 As the forearm is grasped, each of the flexor tendons can be identified by passive flexion of the patient's corresponding digit. Range of motion of the wrist, as well as any deformity or swelling, should be noted. Full forced pronation and supination of the hand without pain virtually eliminates pathology of the distal radioulnar joint or triangular fibro-cartilage complex from consideration. 10 Signs of tendon injuries. (Left) Flexor tendon disruption. (Right) Extensor tendon disruption. FIGURE 6. Signs of tendon injuries. (Left) Flexor tendon disruption. (Right) Extensor tendon disruption. Palpation of the hand usually starts on the ulnar side. The pisiform can be palpated easily in the hypothenar eminence just distal to the distal wrist crease on the palmar ulnar aspect of the hand.

To locate the hook of the hamate, the physician places his or her thumb's IP joint on the patient's pisiform and directs the distal aspect of his or her thumb toward the patient's index finger. When the patient's wrist is flexed, the hook of the hamate can be felt with the tip of the physician's thumb. A fracture of the hook of the hamate usually is not apparent on typical radiographic images of the hand; a carpal tunnel view or computed tomographic scan sometimes is necessary. 11 FIGURE 7. Approximate location of the scaphoid bone. In the flexed position, all fingers should point to the scaphoid. FIGURE 7. Approximate location of the scaphoid bone. In the flexed position, all fingers should point to the scaphoid. The flexor carpi ulnaris, the flexor carpi radialis, and the palmaris longus tendons usually can be observed by having the patient oppose the thumb and fifth finger while flexing the wrist. The flexor carpi ulnaris inserts on the pisiform.

Because 12 to 15 percent of people lack a palmaris longus tendon, care must be taken not to confuse the flexor carpi radialis for the missing tendon. The flexor carpi radialis can be seen distally on the volar radial aspect of the wrist as it crosses the distal palmar crease. In this area, the proximal tubercle of the scaphoid is a prominence that can be palpated easily. If the thumb is placed on the scaphoid tubercle, four fingers can wrap around the distal radius while the wrist is held in ulnar deviation. As the patient radially deviates the wrist, the scaphoid tubercle will volarflex into the physician's thumb. If pressure is directed dorsally with the thumb, pain may be elicited. This reaction may indicate a fractured scaphoid, or a scapholunate instability if an associated “clunk” is noted. This maneuver is termed the Watson or Scaphoid Shift Test 12 ( Figure 8 ). On the dorsum of the wrist, the anatomical snuff-box can be identified easily as the patient abducts and extends the thumb.

The extensor pollicis longus tendon can be identified on the radial aspect of the wrist by having the patient raise the thumb with the palm pronated on a surface. The waist of the scaphoid is located just radial in a depression in the wrist. Pain in this area can be an indication of a scaphoid fracture. 13 The patient's wrist is then held in flexion, and active finger extension with resistance is tested. Significant parascaphoid inflammation, radial carpal, or midcarpal instability will cause considerable pain with this maneuver, known as the Shuck Test 1 ( Figure 9 ). View/Print Figure FIGURE 8. The Watson or Scaphoid Shift Test. (Left) The physician's thumb is placed on the scaphoid tubercle while the patient's wrist is in ulnar deviation. Pressure is applied dorsally. (Right) The patient radially deviates the wrist. Great pain indicates ligamentous instability of the wrist between the scaphoid and the lunate. FIGURE 8. The Watson or Scaphoid Shift Test. (Left) The physician's thumb is placed on the scaphoid tubercle while the patient's wrist is in ulnar deviation.

Pressure is applied dorsally. (Right) The patient radially deviates the wrist. Great pain indicates ligamentous instability of the wrist between the scaphoid and the lunate. The triscaphe joint is located by following the dorsal side of the second finger proximally; the physician's thumb will fall into a recess. The scapholunate joint can be palpated by following the third finger proximally until the thumb falls into a recess, just distal to Lister's tubercle dorsally. Lister's tubercle is a small, mast-like protuberance in the center of the distal radius that is identified by palpating the distal radius while the patient flexes the wrist. The lunate is the most prominent area on the dorsum of a flexed wrist. Kienböck's disease, a post-traumatic avascular necrosis of the lunate, is present in up to 20 percent of patients with lunate fractures. View/Print Figure FIGURE 9. The Shuck Test for perilunate instability. (Left) The wrist is held in flexion by the physician, and the patient extends his or her fingers. (Right) The physician resists this movement.

Significant parascaphoid inflammation, radial carpal, or mid-carpal instability may cause considerable pain with this maneuver. FIGURE 9. The Shuck Test for perilunate instability. (Left) The wrist is held in flexion by the physician, and the patient extends his or her fingers. (Right) The physician resists this movement. Significant parascaphoid inflammation, radial carpal, or mid-carpal instability may cause considerable pain with this maneuver. Pathology References Understanding the surface anatomy of the hand and wrist allows the physician to evaluate common injuries and appreciate less common injuries that might be overlooked on examination. The scaphoid is the most commonly fractured bone of the wrist. Most of these fractures are caused by falling on an outstretched hand. Depending on the patient's age, bone density, and reaction time, this type of fall can result in a fractured scaphoid, scapholunate dislocation, or distal radius fracture. 14 Patients with pain over the anatomical snuff-box should be treated for a possible scaphoid fracture, and a radiograph in what is called the “stretch or navicular view” should be obtained. This type of fracture carries a high likelihood of nonunion.

To prevent supination and pronation of the wrist, the patient should be put into a long arm cast, or a short arm thumb spica splint or cast and shoulder sling; a simple palmar splint or “sugar-tong” splint is inadequate. Patients with negative radiographs should be put into a temporary thumb spica splint for two weeks. When they are reexamined, another radiograph should be taken. If the patient's wrist is not tender and the second A gap of more than 3 mm in the scapholunate joint in a symptomatic patient should alert the physician to consider scapholunate instability until proven otherwise. radiograph is negative, the patient can be instructed to return only if symptoms recur. If the wrist is still tender, further evaluation and a surgical consultation are warranted even if the second radiograph is negative. 15 A fractured hook of the hamate is a less common injury of the wrist that often is not diagnosed because it is not apparent on standard radiographic views. This injury may occur when a patient falls while holding an object, and the object lands between the ground and the ulnar side of the palm.

It also may be caused when a bat hits a ball or a golf club catches the ground, and the hypothenar eminence is struck. Standard radiographs and a “carpal tunnel” view should be obtained in patients with tenderness over the hook of the hamate, and the ulnar nerve should be tested. These patients can be put in an ulnar gutter splint or simple volar splint and referred to a surgeon, because treatment often requires removal of a bone chip. 10 The most common ligamentous instability of the wrist occurs between the scaphoid and the lunate. Patients with injuries of these ligaments often have a high degree of pain even though initial radiographs may appear normal. A gap of more than 3 mm in the scapholunate joint is considered abnormal, and a comparison radiograph of the opposite wrist should be obtained. Physicians should suspect this type of injury if a patient has wrist effusion and pain that is seemingly out of proportion to the injury. Patients with this type of injury often will not tolerate a Watson test. These injuries require an immediate consultation but can be stabilized with a thumb spica splint. 16 Read the full article.

Radial Nerve Palsy - What You Need to Know This material must not be used for commercial purposes, or in any hospital or medical facility. Failure to comply may result in legal action. Radial Nerve Palsy WHAT YOU NEED TO KNOW: What is radial nerve palsy? Radial nerve palsy is a condition that affects the radial nerve. The radial nerve starts in your upper arm and runs down to your wrist and fingers. It controls how your arm and hand move and feel. This condition may go away over time or you may always have it. What causes radial nerve palsy? Pressure: Devices: Devices that press on the radial nerve may cause damage. For example, crutches can put pressure on the nerve in the armpit. A watch can put pressure on the nerve at the wrist. Awkward body positions: Awkward body positions can also put pressure on the nerve. For example, you sleep on your arm or leave it draped over the back of a chair for several hours. Bruises: A bruise that is caused by an injury may put pressure on the radial nerve. Growths: Tumors or cysts (lumps) inside your wrist or arm may press against the nerve.

Fractures (breaks) or dislocations: If you fracture the bone in your upper arm, it may damage the radial nerve. Dislocations happen when joints (where 2 bones meet) in the shoulder or elbow slip out of place. This can also damage the radial nerve. Cuts on your wrist or arm: Cuts can damage or separate the radial nerve. What are the signs and symptoms of radial nerve palsy? Your signs and symptoms depend on where the nerve is damaged. 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. How is radial nerve palsy diagnosed? Your healthcare provider will ask you questions about your symptoms and when they began. He may touch and move your arm and hand to see which muscles are affected.

You may also have any of the following: X-rays: You may need x-rays to check for broken bones or foreign objects in your arm. Magnetic resonance imaging: This test is called an MRI. An MRI may be used to look at the soft tissues and blood vessels in your arm, and to check for cysts or masses. You will need to lie still during this test. The MRI machine contains a very powerful magnet. Never enter the MRI room with any metal objects. This can cause serious injury. Tell your healthcare provider if you have any metal implants in your body. Electromyography and nerve conduction studies: Electromyography (EMG) and nerve conduction studies (NCSs) are tests that measure the electrical activity of your muscles. Your muscles are tested at rest and while you are using them. An EMG test may also check the nerves that control your muscles. NCSs check if your radial nerve is working more slowly than normal. How is radial nerve palsy treated? Recovery time depends on how badly the nerve was damaged. It may take weeks to months for a nerve to heal. In some cases, it may take up to a year to regain normal movement and feeling in your arm or hand.

You may need these or other treatments: Pain medicine: You may be given medicine to take away or decrease pain. Do not wait until the pain is severe before you take your medicine. Splint or cast: You may need a splint or cast to help support your wrist and hand while the radial nerve heals. A splint or cast helps extend your fingers and wrist so you can use them as much as possible. Physical therapy: Physical therapy helps you with special exercises. These exercises help make your bones and muscles strong and flexible. Transcutaneous electrical nerve stimulation: This therapy applies a gentle electric current to your muscles and may help reduce your pain. Surgery: You may need surgery to repair the radial nerve. Ask your healthcare provider for more information about radial nerve surgery. What are the risks of radial nerve palsy? Weakness, numbness, or pain in your arm or hand may be worse with treatment. You may also have long-term swelling, burning, and changes to the color of the skin on your injured arm. Without treatment, you may lose all movement and feeling in your arm or hand. You may have long-term pain. The muscles in your hand may start to tighten and shorten.

This may cause your hand to curl into a fist and you may not be able to use it. When should I contact my healthcare provider? You have a fever. Radial Nerve Dysfunction - Methodist Sports Medicine Radial Nerve Dysfunction Resources Definition Radial nerve dysfunction is a problem with the movement or sensation of the back of the arm (triceps), forearm, or hand. Alternative Names Neuropathy – radial nerve ; Radial nerve palsy Causes Radial nerve dysfunction is a form of peripheral neuropathy. It 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 extension of the wrist and helps in the movement and sensation of the wrist and hand. Dysfunction of a single nerve group (such as the radial nerve) is called mononeuropathy (mono means “one,” and neuropathy means “nerve damage”). With mononeuropathy usually the nerve damage is caused locally. However, systemic disorders (such as mononeuritis multiplex) may occasionally cause nerve damage.

Causes include: ◦ “Crutch palsy,” caused by improper use of crutches ◦ Fracture of the humerus (upper arm bone) ◦ Long-term or repeated constriction of the wrist (caused by wearing a tight watch strap, for example) ◦ Pressure caused by hanging the arm over the back of a chair ◦ Pressure to the upper arm from arm positions during sleep or coma ◦ “Saturday-night palsy” (when the arm is in a position that pinches the nerve during deep sleep, such as when a person is intoxicated) • Long-term pressure on the nerve • Pressure on (compression of) the nerve caused by swelling or injury of nearby body structures These factors may be complicated by a lack of oxygen from decreased blood flow (ischemia) in the area. In some cases, no cause can be found.

Symptoms Symptoms can affect the following: • Hand or forearm (“back” of the hand) • “Thumb side” (radial surface) of the dorsal hand • Fingers nearest the thumb (2nd and 3rd) The following symptoms may occur: • Abnormal sensations • Difficulty extending the arm at the elbow • Difficulty extending the wrist • Numbness, decreased sensation, tingling, or burning sensation • Pain Exams and Tests The health care provider will take a history of your activities and injuries. An examination of the arm, hand, and wrist may identify radial nerve dysfunction. The exam may find: • Decreased ability to extend the arm at the elbow • Decreased ability to rotate the arm outward (supination) • Difficulty lifting the wrist or fingers (extensor muscle weakness) • Muscle loss (atrophy) in the forearm • Weakness of the wrist and finger • Wrist or finger drop In rare cases, it may be difficult to tell radial nerve dysfunction apart from a stroke. Tests for nerve dysfunction may include: • EMG • MRI of the head, neck, and shoulder • Nerve biopsy • Nerve conduction tests Treatment The goal of treatment is to maximize your ability to use the hand and arm.

The health care provider should find and treat the cause appropriately. In most cases, no treatment is needed and you will recover slowly on your own. Surgery to remove masses that press on the nerve may help. CONTROL OF SYMPTOMS • Over-the-counter analgesics or prescription pain medications to control pain (neuralgia) • Phenytoin, carbamazepine, or tricyclic antidepressants (amitriptyline) to reduce stabbing pain • Steroids (prednisone) to reduce swelling Whenever possible, avoid or minimize your use of medications to reduce the risk of side effects. Other treatments include: • Braces, splints, or other appliances to help you use the hand in severe cases • Physical therapy to help maintain muscle strength Occupational therapy, or job counseling, changes, or retraining may be recommended as appropriate. Outlook (Prognosis) If the cause of the nerve dysfunction can be found and successfully treated, there is a possibility that you will fully recover. Disability can range from none to partial or complete loss of movement or sensation. Nerve pain may be uncomfortable and may last for a long period of time.

If this occurs, see a pain specialist to ensure you have access to all pain treatment options. Possible Complications • Mild to severe deformity of the hand • Partial or complete loss of feeling in the hand • Partial or complete loss of wrist or hand movement • Recurrent or unnoticed injury to the hand When to Contact a Medical Professional Call your health care provider if you have had an injury to the arm, and you develop numbness, tingling, or weakness. Prevention The prevention varies depending on the cause. Avoid prolonged pressure on the upper arm. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Radial nerve RADIAL NERVE Fibrous arch attachment of triceps to humerus Lateral intermuscular septum below deltoid insertion Arcade of Frohse: Above supinator & Below elbow Branches Cutaneous nerves to arm: Posterior; Lower lateral Cutaneous nerve to forearm: Posterior Triceps brachii: 3 to 5 branches Anconeus Brachioradialis: Distal to lateral intermuscular septum Extensor carpi radialis longus & brevis Supply lateral & dorsolateral arm & forearm At or below elbow Posterior interosseus nerve (Deep branch): Extensor carpi radialis brevis & Supinator Passes through arcade of Frohse Arcade of Frohse location: Between 2 heads of supinator muscle Passes through the supinator muscle Innervates: All extrinsic wrist extensors except ECRL Finger & thumb extensors Most distal radial innervated muscle: Extensor indicis proprius Extensor carpi ulnaris Sensory: Articular branches to wrist joint External link: Anatomy Lesions DDx from posterior cord of brachial plexus : No deltoid weakness DDx from C7 root : Brachioradialis weakness Pressure palsy (

Triad neuropathy) Usually occurs in sedated or inebriated patients Missile injuries Fingers: Thumb dorsum; Dorsal proximal phalanges 2, 3, 4 NCV Superficial radial SNAPs: Low amplitude Distal radial CMAP: Low amplitude Causes Pressure on medial arm: Compression against humerus Sleep paralysis (Saturday night palsy) Anesthesia Complex fractures or after closed reduction: Surgical exploration Triceps contraction: Sudden; Severe Compression sites: Similar to PIN syndrome Radiocapitellar joint Location: Radial proximal forearm; Lateral elbow Tenderness: Over radial tunnel Provocation: Resisted middle finger extension Worse with repetitive activity Differential diagnosis: Tennis elbow (Lateral epicondylitis); Lateral antebrachial cutaneous nerve compression Motor: Little or no motor weakness Possible treatments: Decompression, Physiotherapy, Steroid injection, Immobilization Origin: Deep motor branch that pierces supinator muscle at elbow level Supplies: Extensor carpi radialis brevis & supinator before entering arcade of Froshe Supplies all extrinsic wrist extensors except Extensor carpi radialis longus Clinical Finger drop: Especially medial 3 fingers; May be patchy Wrist:

 Sparing of Long head of extensor carpi radialis Brachioradialis: Spared Extensor carpi radialis brevis: Proximal branch; May be spared Differential diagnosis: Extensor tendon rupture Sensation: Normal Peripheral Nerve Entrapment and Injury in the Upper Extremity - American Family Physician Peripheral Nerve Entrapment and Injury in the Upper Extremity SARA L.

NEAL, MD, MA, and KARL B. FIELDS, MD, Moses Cone Health System, Greensboro, North Carolina Am Fam Physician. 2010 Jan 15;81(2):147-155. This version of the article includes supplemental content. References Peripheral nerve injury of the upper extremity commonly occurs in patients who participate in recreational (e.g., sports) and occupational activities. Nerve injury should be considered when a patient experiences pain, weakness, or paresthesias in the absence of a known bone, soft tissue, or vascular injury. The onset of symptoms may be acute or insidious. Nerve injury may mimic other common musculoskeletal disorders. For example, aching lateral elbow pain may be a symptom of lateral epicondylitis or radial tunnel syndrome; patients who have shoulder pain and weakness with overhead elevation may have a rotator cuff tear or a suprascapular nerve injury; and pain in the forearm that worsens with repetitive pronation activities may be from carpal tunnel syndrome or pronator syndrome.

Specific history features are important, such as the type of activity that aggravates symptoms and the temporal relation of symptoms to activity (e.g., is there pain in the shoulder and neck every time the patient is hammering a nail, or just when hammering nails overhead?). Plain radiography and magnetic resonance imaging are usually not necessary for initial evaluation of a suspected nerve injury. When pain or weakness is refractory to conservative therapy, further evaluation (e.g., magnetic resonance imaging, electrodiagnostic testing) or surgical referral should be considered. Recovery of nerve function is more likely with a mild injury and a shorter duration of compression. Recovery is faster if the repetitive activities that exacerbate the injury can be decreased or ceased. Initial treatment for many nerve injuries is nonsurgical. Peripheral nerve injury in the upper extremity is common, and certain peripheral nerves are at an increased risk of injury because of their anatomic location. Risk factors include a superficial position, a long course through an area at high risk of trauma, and a narrow path through a bony canal. The anatomy and function of upper extremity nerve roots, as well as specific risk factors of injury, are described in Online Table A .

The most common nerve entrapment injury is carpal tunnel syndrome, which has an estimated prevalence of 3 percent in the general population and 5 to 15 percent in the industrial setting. 1 Given the potential for longstanding impairment associated with nerve injuries, it is important for the primary care physician to be familiar with their presentation, diagnosis, and management. SORT: KEY RECOMMENDATIONS FOR PRACTICE Clinical recommendation Evidence rating References Patients with a brachial plexus nerve injury (i.e., stinger) should undergo periodic reexamination for two weeks after the injury. Continued or new symptoms should be evaluated using neuroimaging and electrodiagnostics because a more severe nerve injury is likely. C For patients with a carpal tunnel syndrome diagnosis based on typical history and physical examination findings, electrodiagnostic testing does not usually change the diagnosis. C Symptom relief from splinting, corticosteroid injections, and other conservative modalities for carpal tunnel syndrome have similar outcomes. Surgical intervention has been shown to have better outcomes than splinting.

B A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to . SORT: KEY RECOMMENDATIONS FOR PRACTICE Clinical recommendation Evidence rating References Patients with a brachial plexus nerve injury (i.e., stinger) should undergo periodic reexamination for two weeks after the injury. Continued or new symptoms should be evaluated using neuroimaging and electrodiagnostics because a more severe nerve injury is likely. C For patients with a carpal tunnel syndrome diagnosis based on typical history and physical examination findings, electrodiagnostic testing does not usually change the diagnosis. C Symptom relief from splinting, corticosteroid injections, and other conservative modalities for carpal tunnel syndrome have similar outcomes. Surgical intervention has been shown to have better outcomes than splinting.

B Anatomy and Related Risk Factors of Upper Extremity Nerve Injury Nerve Risk factors for injury Axillary From brachial plexus, around humeral head, through the quadrilateral space to deltoid/teres minor Quadrilateral space boundaries: humeral neck, teres major and minor, long head of triceps Motor: deltoid, teres minor Sensory: skin over lower half of the deltoid Humeral head compresses nerve during extreme abduction Upward pressure through the axilla Shoulder dislocation Compression in quadrilateral space Long thoracic C5 to C7 merge, travel between clavicle and first rib through axilla to serratus anterior muscle Long nerve: 20 to 22 cm Motor: serratus anterior Sensory: none Sudden upper extremity traction Shoulder depression with contralateral neck flexion Prolonged compression (backpacker's palsy) Median Brachial plexus down anterior arm, at antecubital fossa passes through radial tunnel, dives between two heads of pronator muscle, under flexor digitorum superficialis, through carpal tunnel Motor: Injury at elbow or forearm: Weak wrist flexion, no interphalangeal flexion of thumb, index, and

 long digit Injury at wrist: none or weak thumb abduction Sensory: Injury at elbow: proximal forearm pain Injury at wrist: sensory loss in the thumb, radial 2.5 digits, and thenar eminence Injury at elbow or forearm: radial tunnel, within pronator teres muscle, under flexor digitorum superficialis Injury at wrist: carpal tunnel syndrome Musculocutaneous C5 to C7 merge into lateral cord brachial plexus, goes through axilla, under coracobrachialis, through biceps and under deep fascia at the elbow Motor: Injury at shoulder: loss in biceps, coracobrachialis, and brachialis Injury at elbow: none Sensory: radial side of forearm (dorsal and volar), but not hand Shoulder dislocation Hypertrophy of the coracobrachialis Deep brachial fascia of elbow as nerve exits biceps (sensory symptoms only) Radial From brachial plexus, through axilla, down posterior arm until it circles toward anterior arm at spiral groove of the humerus; down anterior arm and enters radial tunnel just above the lateral epicondyle Divides into superficial and deep (posterior interosse

us nerve) branches Motor: Injury in axilla: loss of elbow flexion; weak wrist and digit extension; weak forearm supination Injury at elbow: superficial branch (radial tunnel): forearm pain, normal motor; posterior interosseus nerve: weak or no wrist extension Injury at wrist: no motor loss Sensory: variable sensory loss in distal forearm or hand Injury at elbow: no sensory loss; possible pain with repetitive forearm supination Injury in axilla or proximal humerus (fracture) Injury at elbow: radial tunnel or area of proximal radius (fracture or dislocation); two nerve branches from elbow have injury potential, posterior interosseus nerve has mostly motor loss and the superficial branch has only sensory change (pain) Spinal accessory Emerges through sternocleidomastoid muscle, across posterior neck, dives under trapezius Motor: trapezius Sensory: none Very superficial course in posterior neck and directly under the trapezius muscle Suprascapular From upper trunk brachial plexus, through posterior triangle, across top of scapula and through scapular notch, down posterior aspect scapula and across scapular spine to supraspinatus, infras

pinatus Motor: supraspinatus, infraspinatus Sensory: acromioclavicular and glenohumeral joints Entrapment under transverse scapular ligament that covers the suprascapular notch Injury as it crosses scapular spine or under spinoglenoid ligament Ulnar From brachial plexus down anterior arm; just above medial epicondyle it passes to the posterior compartment and into the cubital tunnel; down ulnar side of forearm into Guyon canal (boundaries are hamate and pisiform bones); splits into deep (motor) and superficial (sensory) branches in canal Motor: no loss or weak thumb adduction, weak digit abduction, and adduction toward center of long digit Sensory: Injury at elbow: pain ulnar side of forearm with or without paresthesias in ulnar digits Injury at wrist: paresthesias in ulnar digits Injury at elbow or forearm: cubital tunnel, ulnar nerve irritation with medial collateral ligament deficiency Injury at wrist: Guyon canal Upper trunk cervical plexus Nerve roots C5 and C6 as they exit vertebral foramina and form upper trunk brachial plexus Motor: infras

pinatus, supraspinatus, biceps, and deltoid Sensory: C5 and C6 dermatomes No protective coverings (epineurium and perineurium) on the nerves after they exit the foramina Increased risk of stretch injury at neck and shoulder regions Contusion or compression of upper trunk at Erb point Information from Snell RS.

Clinical Anatomy for Medical Students. 4th ed. Boston, Mass.: Little, Brown; 1992; and Netter FH, Colacino S. Atlas of Human Anatomy. Summit, N.J.: CIBA-GEIGY Corp; 1989. Online Table A.

Anatomy and Related Risk Factors of Upper Extremity Nerve Injury Nerve Risk factors for injury Axillary From brachial plexus, around humeral head, through the quadrilateral space to deltoid/teres minor Quadrilateral space boundaries: humeral neck, teres major and minor, long head of triceps Motor: deltoid, teres minor Sensory: skin over lower half of the deltoid Humeral head compresses nerve during extreme abduction Upward pressure through the axilla Shoulder dislocation Compression in quadrilateral space Long thoracic C5 to C7 merge, travel between clavicle and first rib through axilla to serratus anterior muscle Long nerve: 20 to 22 cm Motor: serratus anterior Sensory: none Sudden upper extremity traction Shoulder depression with contralateral neck flexion Prolonged compression (backpacker's palsy) Median Brachial plexus down anterior arm, at antecubital fossa passes through radial tunnel, dives between two heads of pronator muscle, under flexor digitorum superficialis, through carpal tunnel Motor: Injury at elbow or forearm: Weak wrist flexion, no interphalangeal flexion of thumb, index, and

 long digit Injury at wrist: none or weak thumb abduction Sensory: Injury at elbow: proximal forearm pain Injury at wrist: sensory loss in the thumb, radial 2.5 digits, and thenar eminence Injury at elbow or forearm: radial tunnel, within pronator teres muscle, under flexor digitorum superficialis Injury at wrist: carpal tunnel syndrome Musculocutaneous C5 to C7 merge into lateral cord brachial plexus, goes through axilla, under coracobrachialis, through biceps and under deep fascia at the elbow Motor: Injury at shoulder: loss in biceps, coracobrachialis, and brachialis Injury at elbow: none Sensory: radial side of forearm (dorsal and volar), but not hand Shoulder dislocation Hypertrophy of the coracobrachialis Deep brachial fascia of elbow as nerve exits biceps (sensory symptoms only) Radial From brachial plexus, through axilla, down posterior arm until it circles toward anterior arm at spiral groove of the humerus; down anterior arm and enters radial tunnel just above the lateral epicondyle Divides into superficial and deep (posterior interosse

us nerve) branches Motor: Injury in axilla: loss of elbow flexion; weak wrist and digit extension; weak forearm supination Injury at elbow: superficial branch (radial tunnel): forearm pain, normal motor; posterior interosseus nerve: weak or no wrist extension Injury at wrist: no motor loss Sensory: variable sensory loss in distal forearm or hand Injury at elbow: no sensory loss; possible pain with repetitive forearm supination Injury in axilla or proximal humerus (fracture) Injury at elbow: radial tunnel or area of proximal radius (fracture or dislocation); two nerve branches from elbow have injury potential, posterior interosseus nerve has mostly motor loss and the superficial branch has only sensory change (pain) Spinal accessory Emerges through sternocleidomastoid muscle, across posterior neck, dives under trapezius Motor: trapezius Sensory: none Very superficial course in posterior neck and directly under the trapezius muscle Suprascapular From upper trunk brachial plexus, through posterior triangle, across top of scapula and through scapular notch, down posterior aspect scapula and across scapular spine to supraspinatus, infras

pinatus Motor: supraspinatus, infraspinatus Sensory: acromioclavicular and glenohumeral joints Entrapment under transverse scapular ligament that covers the suprascapular notch Injury as it crosses scapular spine or under spinoglenoid ligament Ulnar From brachial plexus down anterior arm; just above medial epicondyle it passes to the posterior compartment and into the cubital tunnel; down ulnar side of forearm into Guyon canal (boundaries are hamate and pisiform bones); splits into deep (motor) and superficial (sensory) branches in canal Motor: no loss or weak thumb adduction, weak digit abduction, and adduction toward center of long digit Sensory: Injury at elbow: pain ulnar side of forearm with or without paresthesias in ulnar digits Injury at wrist: paresthesias in ulnar digits Injury at elbow or forearm: cubital tunnel, ulnar nerve irritation with medial collateral ligament deficiency Injury at wrist: Guyon canal Upper trunk cervical plexus Nerve roots C5 and C6 as they exit vertebral foramina and form upper trunk brachial plexus Motor: infras

pinatus, supraspinatus, biceps, and deltoid Sensory: C5 and C6 dermatomes No protective coverings (epineurium and perineurium) on the nerves after they exit the foramina Increased risk of stretch injury at neck and shoulder regions Contusion or compression of upper trunk at Erb point Information from Snell RS.

Clinical Anatomy for Medical Students. 4th ed. Boston, Mass.: Little, Brown; 1992; and Netter FH, Colacino S. Atlas of Human Anatomy. Summit, N.J.: CIBA-GEIGY Corp; 1989. Pathophysiology References The three categories of nerve injuries are neurapraxia, axonotmesis, and neurotmesis. Neurapraxia is least severe and involves focal damage of the myelin fibers around the axon, with the axon and the connective tissue sheath remaining intact. Neurapraxia typically has a limited course (i.e., days to weeks). Axonotmesis is more severe, and involves injury to the axon itself. Regeneration of the nerve is possible, but typically prolonged (i.e., months), and patients often do not have complete recovery. Neurotmesis involves complete disruption of the axon, with little likelihood of normal regrowth or clinical recovery. 2 , 3 Most nerve injuries result in neurapraxia or axonotmesis. Mechanisms of nerve injury include direct pressure, repetitive microtrauma, and stretch- or compression-induced ischemia.

The degree of injury is related to the severity and extent (time) of compression. 4 General Diagnostic Approach References Nerve injury should be considered when a patient reports pain, weakness, or paresthesias that are not related to a known bone, soft tissue, or vascular injury. Symptom onset may be insidious or acute. The location of symptoms, the type of symptom (i.e., paresthesias, pain, weakness), and any relation between a symptom and specific activity should be determined. Table 1 outlines the differential diagnosis of upper extremity nerve injury by symptom and area of the body. 5 , 6 Symptoms of Upper Extremity Nerve Injuries Anatomic area Ulnar at wrist or elbow Weakness Information from references 5 and 6 . Table 1. Symptoms of Upper Extremity Nerve Injuries Anatomic area Ulnar at wrist or elbow Weakness Information from references 5 and 6 . Initial physical examination of a patient with an upper extremity injury includes looking for the presence of a radial pulse, and sensation and movement in the digits. If there is no obvious neurovascular compromise, the remainder of the examination is based on the patient's history.

The examination should follow the classic pattern of inspection, palpation, joint range of motion, muscle strength testing, and sensory and neurologic examination. It is helpful to understand the nerves commonly involved, their function, and the corresponding areas of the body at risk of compression or entrapment. Figures 1 and 2 show typical distributions of nerves in the upper extremity. 7 Posterior and anterior views of upper limb cutaneous innervation. Information from reference 7 . Posterior and anterior views of upper limb cutaneous innervation. Information from reference 7 . Posterior and anterior views of upper limb dermatomes. Information from reference 7 . Posterior and anterior views of upper limb dermatomes. Information from reference 7 . Common Nerve Injuries and Entrapment Syndromes of the Upper Extremity Jump to section + Tables 2 through 4 outline the evaluation process and differential diagnosis of nerve injuries to the upper extremity. 5 , 6 SHOULDER AND ARM Axillary Nerve: Quadrilateral Space Syndrome. The axillary nerve is vulnerable to trauma as it passes through the quadrilateral space.

Injury can occur from shoulder dislocation; upward pressure (e.g., from improper crutch use); repetitive overload activities (e.g., pitching a ball, swimming); and arthroscopy or rotator cuff repair. The typical symptom is arm fatigue with overhead activity or throwing. There may be associated paresthesias of the lateral and posterior upper arm. Examination reveals weak lateral abduction and external rotation of the arm. Brachial Plexus Nerve: Stinger. A brachial plexus injury (i.e., stinger) is common in persons who play football, but it also occurs with other collision sports. The classic presentation is acute onset of paresthesias in the upper arm. A key characteristic is a circumferential rather than dermatomal pattern of paresthesias. Symptoms typically last seconds to minutes. Motor symptoms may be present initially or develop later. A brachial plexus injury must be differentiated from a cervical spine injury. The initial examination should focus on the neck, with palpation of the cervical vertebrae to detect point tenderness and evaluation of neck range of motion. Any indication of a cervical spine injury mandates further emergent neurologic and radiologic evaluation.

Point tenderness of the cervical vertebrae or pain with neck movement is a red flag for a cervical spine injury, in which case the patient should be immobilized. Bilateral symptoms or those involving upper and lower extremities are less likely to be from a brachial plexus injury. If motor symptoms occur, the upper extremity muscle group exhibiting weakness correlates with the part of the brachial plexus that has been injured. Because motor symptoms may occur hours to days after the injury, repeated neurologic examinations are necessary—the patient should be reevaluated after 24 hours and then at least every few days for two weeks. If new symptoms or significant worsening of existing symptoms occurs, neuroimaging, electrodiagnostics, or surgical referral should be considered. 8 Patients who have multiple occurrences of stingers should also have a more thorough workup, because they may have an underlying neck pathology that predisposes them to this injury. 9 , 10 Occurrence during participation in a sporting event raises the issue of return to play. If all symptoms resolve within 15 minutes and there is no concern for cervical spine injury, the player may return to the same event with at least one repeat examination during that event.

11 Long Thoracic Nerve. Injury to the long thoracic nerve occurs acutely from a blow to the shoulder, or with activities that involve chronic repetitive traction on the nerve (e.g., tennis, swimming, baseball). Presenting symptoms include diffuse shoulder or neck pain that worsens with overhead activities. Examination reveals scapular winging and weakness with forward elevation of the arm. Spinal Accessory Nerve. Injury to the spinal accessory nerve can occur with trapezius trauma or shoulder dislocation. Radical neck dissection, carotid endarterectomy, and cervical node biopsy are iatrogenic sources of injury. Patients usually present with generalized shoulder pain and weakness. Examination of the shoulders reveals asymmetry. The affected side appears to sag and the patient is unable to shrug the shoulder toward the ear. Associated weakness of forward arm elevation above the horizontal plane is common. With chronic injury, the trapezius may atrophy. Suprascapular Nerve. Injury to the suprascapular nerve is associated with repetitive overhead loading. The suprascapular nerve serves the supraspinatus and infraspinatus muscles.

The infraspinatus may be the only muscle affected, depending on the site of injury. Loss of infraspinatus function presents as weak external rotation of the arm. Supraspinatus involvement additionally presents with weak arm elevation, which is most pronounced in the range of 90 to 180 degrees. Suprascapular nerve injury can result from other shoulder pathologies, specifically a glenoid labrum tear. Cyst formation at the suprascapular notch from a labral tear is not uncommon. The cyst compresses the suprascapular nerve, affecting the supraspinatus and infraspinatus muscles. 12 Suprascapular nerve injury and rotator cuff tear both lead to supraspinatus and infraspinatus weakness. Differentiating the two injuries may require magnetic resonance imaging (MRI). Information from references 5 and 6 . FOREARM AND ELBOW Median Nerve at the Elbow: Pronator Syndrome. The pronator teres muscle in the forearm can compress the median nerve, which may cause symptoms that mimic carpal tunnel syndrome. Symptoms are discomfort and aching in the forearm with activities requiring repetitive pronation of the forearm, especially with the elbow extended.

Paresthesias in the thumb and first two digits may be present. Forearm sensation is normal, and sensation of the digits may also be normal. In pronator syndrome, there is sensory loss over the thenar eminence, which is not a finding of carpal tunnel syndrome. Results of the Tinel sign and Phalen maneuver at the wrist should be negative in patients with pronator syndrome. 13 Radial Nerve at the Elbow: Radial Tunnel and Posterior Interosseous Nerve Syndromes. The radial nerve divides into a superficial branch (sensory only) and a deep branch (posterior interosseous nerve) at the lateral elbow. Forearm pain that is exacerbated by repetitive forearm pronation is the presenting symptom of radial tunnel syndrome, which involves injury to the superficial branch of the radial nerve. Symptoms of radial tunnel syndrome are almost identical to those of tennis elbow (i.e., lateral epicondylitis), and distinguishing the two can be difficult because physical examination maneuvers that aggravate radial tunnel syndrome may also be positive in patients with tennis elbow (e.g., supination against resistance with the elbow and wrist extended, and resisted extension of the middle finger).

14 A differentiating factor is the point of maximal tenderness. In radial tunnel syndrome, this point is over the anterior radial neck; in tennis elbow, it is at the origin of the extensor carpi radialis brevis muscle. The presence of any motor symptoms is more likely related to injury of the posterior interosseus nerve, which supplies the extensor muscles of the hand. Generalized hand weakness is the presenting symptom of posterior interosseus nerve syndrome. Examination reveals weakness of digit and wrist extension, although this is usually more prominent in the digits than in the wrist. Ulnar Nerve at the Elbow: Cubital Tunnel Syndrome. The ulnar nerve at the elbow is very superficial and at risk of injury from acute contusion or chronic compression. Compression can be from an external or internal source. As the elbow flexes, the cubital tunnel volume decreases, causing internal compression. Cubital tunnel syndrome may cause paresthesias of the fourth and fifth digits. There may be elbow pain radiating to the hand, and symptoms may be worse with prolonged or repetitive elbow flexion. Paresthesias precede clinical examination findings of sensory loss. Weakness may occur, but is a late symptom.

When present, motor findings are weak digit abduction, weak thumb abduction, and weak thumb-index finger pinch. Power grip is ultimately affected. Information from references 5 and 6 . HAND AND WRIST Median Nerve at the Wrist: Carpal Tunnel Syndrome. Carpal tunnel syndrome is the most common nerve entrapment injury. 15 Early symptoms are paresthesias of the thumb, index digit, and long digit. Some patients also have forearm pain. The most helpful physical examination findings are hypalgesia (positive likelihood ratio of 3.1) and abnormality in a Katz hand diagram. 16 Although commonly used in patients with carpal tunnel syndrome, Tinel sign and Phalen maneuver are less accurate. 16 The sensory examination is normal initially, although late findings include sensory loss in the median nerve distribution, weak thumb abduction, and thenar atrophy. Electrodiagnostic testing can be useful and quantitates severity of entrapment, although false negatives and false positives may occur. 16 , 17 Radial Nerve at the Wrist: Handcuff Neuropathy. The superficial branch of the radial nerve crosses the volar wrist on top of the flexor retinaculum of the carpal tunnel.

It is vulnerable to compression by anything wound tightly around the wrist. Historically, this is an area easily injured by tight handcuffs, thus the name “handcuff neuropathy.” The injury leads to numbness on the back of the hand, mostly on the radial side. Examination may reveal decreased sensation to soft touch and pinprick over the dorsoradial hand, dorsal thumb, and index digit. Motor function is typically intact. Ulnar Nerve at the Wrist: Cyclist's Palsy. Injury of the ulnar nerve at the wrist is common in cyclists because the ulnar nerve gets compressed against the handlebar during cycling, resulting in “cyclist's palsy.” This type of nerve injury occurs with other activities involving prolonged pressure on the volar wrist (e.g., jackhammer use). Symptoms are paresthesias in the fourth and fifth digits. Digit weakness is uncommon because the motor portion of the nerve at the wrist is less superficial. Unless the activity is prolonged or chronic, results of the sensory examination are normal and numbness will resolve within a few hours after stopping the activity. References IMAGING Plain radiography is primarily useful for identifying other diagnoses, such as fracture or cervical spondyloarthropathy.

MRI is rarely needed for initial evaluation of a typical nerve injury, although it may be helpful for specific nerves ( Table 5 ). 18 Chronic nerve injury can lead to denervation changes in muscle. These changes may be visible on MRI as abnormal signal patterns. A normal MRI finding does not rule out nerve injury. Newer techniques, such as gadofluorine M–enhanced MRI, may ultimately be able to assess nerve regeneration. 19 Ultrasonography is a less expensive modality to define anatomic entrapment, but its use is limited by lack of standardization of technique and interpretation. 20 Radial Tunnel Syndrome (Radial Nerve Entrapment) - Plano Orthopedic Sports Medicine & Spine Center Plano Orthopedic Sports Medicine & Spine Center Radial Tunnel Syndrome (Radial Nerve Entrapment) You are here: Home » Radial Tunnel Syndrome (Radial Nerve Entrapment) What is it? Radial Tunnel Syndrome is a condition thought to be a compression injury to the radial nerve, which runs by the bones and muscles of the forearm and elbow. This condition can often be confused with tennis elbow.

It most often occurs due to repetitive motions such as pushing or pulling, twisting, gripping with the hand or bending the wrist. It can also be caused by a direct trauma to the area or injury. Symptoms Radial Tunnel Syndrome symptoms include, cutting, piercing, or stabbing pain at the top of the forearm or back of the hand, especially when you try to extend or straighten your wrist and fingers. Unlike the cubital tunnel syndrome patients rarely feel numbness or tingling because this particular nerve affects the muscle. The pain worsens when the arm is being used. Treatment Treatment options include rest, immobilization with a splint, cushioning of the nerve with an elbow pad, and anti-inflammatory medications. Your physician may perform an EMG (electromyography), a nerve conduction study or both to properly diagnosis this condition. This will allow them to identify the area of nerve damage and determine the severity of damage that occurred to the nerve. In some cases surgery may be performed to alleviate the pressure on the radial nerve. Watch a video to learn more Our Patients’ Voice I wish every single doctor office ran like Plano Orthopedic. Efficient, on schedule, knowledgeable and friendly. I recommend this place to everyone.

2016-02-02T09:14:04+00:00 I wish every single doctor office ran like Plano Orthopedic. Efficient, on schedule, knowledgeable and friendly. I recommend this place to everyone. Our Patients’ Voice The best part of the visit was the friendly family attitude that older people value -- no cold professional hurried treatment. I highly recommend Plano Orthopedic. 2016-02-02T09:23:57+00:00 The best part of the visit was the friendly family attitude that older people value -- no cold professional hurried treatment. I highly recommend Plano Orthopedic. Our Patients’ Voice Everyone is great at what they do and they compliment each other's jobs and positions. Great office. 2016-02-02T09:24:15+00:00 Everyone is great at what they do and they compliment each other's jobs and positions. Great office.

Question: In medicine, which joint is controlled by the Radial Nerve?
Answer: WRIST