Numbness In the Arm

This article provides a list disorders that cause numbness only or mainly in the arm (including shoulder, hand and fingers). Read about disorders that cause numbness in BOTH arms (hands) and legs (feet).

“Everyday” Causes of Numbness In the Arm

Pressure On the Arm

An external object can press on nerves or vessels in the arm, resulting in numbness, tingling, or temporary paralysis of the arm.

  • Sitting with the upper arm hanging over the back of the chair presses on brachial plexus and vessels in the upper arm.
  • Wearing straps, or carrying a bag or rucksack can press on nerves in the shoulder.
  • Inflated cuff during measuring the blood pressure closes arteries in the arm.

Raising Arms Above the Level of the Heart

When someone works with hands raised above his/her head, heart may not be able to push enough blood into the arms, so nerves don’t get enough oxygen, and numbness, tingling, numbness and partial paralysis may occur as fast as in few minutes. The same may happen during sleeping with arms above the level of the heart.

Cold

Hands and fingers can get numb and even partly paralysed in cold weather, due to narrowing of peripheral arteries that can’t deliver enough oxygen to nerves supplying hands and fingers.

Causes of Constant or Recurrent Numbness In the Arm

SPINAL DISORDERS

Cervical Disk Syndrome

Cervical disc syndrome (cervical discs are cartilaginous plates lying between bony parts of the backbone in the neck) results from compression of nerve roots arising from the neck part of the spinal cord. It is caused by disc herniation, degeneration, or hyper-extension injury (head moves rapidly toward the back) of the neck backbone. A herniation may develop suddenly or gradually over weeks or months and result in the following symptoms:

  • position/movement dependent pain, tingling or numbness in the neck, shoulders, between the shoulder blades, in the arm, hand or fingers (when nerve roots are compressed)
  • stumbling gait, difficulty with fine arm and hand moves, and tingling in the body or legs (when the spinal cord is compressed)

Diagnosis is made by CT, MRI or myelography. Therapy includes immobilization, cold therapy followed by heat therapy, cervical traction, analgesics, muscle relaxants, physical therapy or surgical decompression of nerve roots or spinal cord.

Cervical Spondylosis

Cervical spondylosis is an age related deformation of the bony and cartilaginous parts of the neck backbone which can press on the spinal cord or nerve roots. Symptoms, diagnosis and treatment resemble those in the cervical disc syndrome (see above).

BRACHIAL PLEXUS

Thoracic Outlet Syndrome

Thoracic outlet is a space between clavicle (collar bone), first rib and corresponding ligaments through which nerves and vessels travel from the base of the neck toward the armpit. Thoracic outlet syndrome (TOS) is a group of disorders characterized by neck, shoulder and arm pain resulting from compression of the subclavian artery or vein (that give blood supply to the arm) or brachial plexus (from which nerves to the arm arise). Causes include injuries, and forced repeated movements e.g. in athletes, swimmers, or weight lifters. Symptoms:

  • muscle wasting at the base of the thumb, numbness, feeling of pins and needles, or pain in the shoulder, armpit, arm or the hand (when nerves are compressed)
  • pale, cool arm with weakened arm pulses, numbness and pain (when vessels are compressed)

Disorders of Brachial Plexus

The brachial plexus is formed by lower four cervical nerves (C5-C8) and the first thoracic nerve (Th1). The plexus extends from the lower part of the side of the neck to the armpit. From brachial plexus all main nerves to the arm (axillary, musculocutaneus, ulnar, radial, and median nerve) arise.

Picture 1. Arm dermatomes (img source: wikimedia.org)

Brachial Plexus Injuries

Most of brachial plexus injuries usually occur in a car, motorcycle and sport accidents, during birth, or in bullet or knife wounds. Symptoms and prognosis depend on the nerves involved and extent of their inury: nerve stretching, scar tissue (neuroma), partial or complete nerve rupture or nerve avulsion – tearing of nerve from spinal cord. One or more of the following symptoms may appear::

  • a limp or paralyzed arm
  • severe pain, especially in the neck and shoulders, but also in the arm
  • numbness in the arm or hand
  • diminished arterial pulses in the arm

Some brachial plexus injuries may heal without treatment. Many children who are injured during birth improve or recover by 3 to 4 months of age. Treatment for brachial plexus injuries includes physical therapy or, if necessary, surgery.

Acute brachial neuritis is a rare inflammation of brachial plexus, supposedly caused by an autoimmune reaction, may occur at any age, but primarily in young men. Symptoms:

  • severe pain in the upper arms and shoulders
  • the arm becomes weak and numb, and reflexes are impaired as the pain resolves. Weakness develops within 3 to 10 days. Then people typically regain their strength over the next few months.

Radiation-Induced Brachial Plexopathy

Radiation-induced brachial plexopathy can occur when radiotherapy is directed at the chest, axillary region, thoracic outlet, or neck. The mechanism is believed to be a combination of localized ischemia and failure of cellular proliferation. The net result is fibrosis of the neural and perineural soft tissues secondary to microvascular insufficiency. Symptoms may appear months to years after radiation therapy and may include:

  • numbness
  • swelling
  • weakness
  • pain in the arm

Broken Shoulder Blade

Shoulder blade (scapula) is a bone on the upper back that connects collar bone (clavcle) and arm bone (humerus). Broken shoulder blade (usually in car or motorbike accidents) may result in:

  • swelling, pain, bruising, or bleeding in the injured area, shoulder may look misshapen
  • weakness, numbness or tingling in the shoulder or arm

ARM INJURIES

Broken Arm, Wrist, Hand or Finger

The term broken arm includes fractures of arm bone (humerus), elbow, and bones of the forearm (radius and ulna). Symptoms depend on the site of injury and usually include:

  • severe pain, which may increase with movement
  • swelling, tenderness and bruising
  • obvious deformity
  • stiffness or inability to move your arm, hand or finger
  • weakness, numbness or tingling in the arm, hand or fingers

Ulnar Neuropathy (Cubital Tunnel Syndrome)

Ulnar nerve entrapment occurs when the ulnar nerve in the arm becomes compressed. Ulnar nerve arises from plexus and travels under the collar bone, downside along the inner side of the upper arm, behind the inner part of the elbow (lat. cubitus), where it can be felt as a “funny bone” and then down to the wrist, hand and little and ring finger. The cause of ulnar nerve entrapment is usually an overuse of the elbow e.g. in cyclists, or typists. Symptoms include:

  • the hand, 4th and 5th finger fall asleep and are numb, especially after bending the elbow
  • movements of 4th and 5th finger may be limited (”handlebar palsy” in cyclists)
  • sensitivity of the hand on the little finger side to the cold
  • pain on the inner side of the elbow

Prevention is by avoiding excessive elbow use. Treatment includes special arm exercises, anti-inflammatory drugs like ibuprofen. Broken elbow may also result in ulnar nerve entrapment.

WRIST AND HAND

Carpal Tunnel Syndrome

Carpal tunnel syndrome (Latin carpus = wrist) is a painful condition of the wrist, hand and fingers, triggered by repetitive use of the wrist, and caused by the pressure of swollen wrist tissues on the median nerve. It often appears in assembly line workers, computer workers, musicians, mechanics, tennis players etc. Bone spurs in rheumatoid arthritis, or fluid in hypothyroidism, kidney disease or menopausemay also press on the median nerve. Symptoms usually start gradually and may include:

  • tingling or numbness in the first four fingers (thumb, index, middle and ring) and corresponding part of the hand
  • pain in the wrist, palm, or forearm
  • difficulty grasping small objects or gripping
  • pain at night

Ganglion Cyst

Ganglion cyst (Greek ganglion = tumor, cyst = fluid filled sac) is a soft lump, usually appearing on the back of the hand in people between 20-40 years of age. It is a noncancerous fluid filled sack arising from tendon sheets or capsule of the joint from unknown reason. It may not be always seen from the outside. Ganglyon cysts are common in gymnasts. Symptoms:

  • a soft lump or lumps of various size (may be over 3 cm), on the back of the hand, inner side of the wrist, base of the finger, or on the finger tip (on the last finger joint).
  • pain or numbness in the wrist, hand or finger(s)


Raynaud’s Disease

Raynaud’s disease is a painful finger condition due to spasms in finger arteries. Disease may also affect toes, or rarely nose, ears, lips and nipples. The cause is not known. Symptoms are triggered by cold (even short term cold like taking something from a freezer), or strong emotions and include:

  • Look pale due to lack of blood flow
  • Look bluish due to a lack of oxygen
  • Feel numb, cold, or painful
  • Redden and throb or tingle as blood returns to the affected area
  • Attacks usually last about 15 minutes. They can last less than a minute or as long as several hours. Attacks can occur daily or weekly.Sometimes attacks affect only one or two fingers or toes. Different areas may be affected at different times. Attacks can cause sores or tissue death (gangrene) in people with severe secondary Raynaud’s. However, severe Raynaud’s is very uncommon.

Raynaud’s Phenomenon

Raynaud’s phenomenon is like Raynaud’s disease, but the causes is known. Most often causes are connective tissue diseases like scleroderma, systemic lupus erythematosus, Sjögren’s syndrome, dermatomyositis, and polymyositis.

Other possible causes: carpal tunnel syndrome, obstructive arterial disease, anti-hypertensive drugs, ergotamine (used for migraine), chemotherapeutic medications.

Workers exposed to vinyl chloride, or work with vibrating tools may develop Raynaud’s phenomenon. Typist, and piano players are also vulnerable to the disorder.

As a complication, painful ulcers and gangrene (tissue death) on fingers may appear.

Diagnosis of the Cause of Arm Numbness

History of arm numbness. Knowing an exact time course of tingling or numbness, and eventual arm weakness, head or legs involvement, history of arm or neck injuries, repetitive elbow or wrist use, reactions to cold, hypothyroidism, diabetes, menopause may give a strong evidence about the cause.

Neurologic examination. Testing of sensitivity of particular arm dermatome can reveal which nerves are involved.

Imaging. X-ray may reveal arthritis in the neck spine, or a broken arm bone. Myelography can reveal herniated disc or narrowed spinal canal. MRI and CT show soft tissues like tumors.

Electromiography (EMG) and nerve conduction studies show the nature of the nerve damage. Together with imaging they are important to evaluate the extent of brachial plexus injury.

Blood testscan reveal diabetes, abnormalities in serum levels of sugar (diabetes), calcium, potassium, sodium, magnesium, vitamins B6 or B12, thyroxine (hypothyroidism), sex hormones (menopause).

Cold simulation test may reveal Raynaud’s disease or phenomenon.

Treatment of Arm Numbness

Firstly, the cause of numbness should be treated if possible.

Non-steroid anti-rheumatic drugs like ibuprofen, or antidepressants, may relieve pain and numbness.

Rest and immobilization of the neck, shoulder, elbow, wrist, or the whole arm is sometimes necessary after an injury, or when joint movements contribute to nerve irritation, like in ulnar nerve entrapment or carpal tunnel syndrome.

Physical therapy may help when bones, articles and muscle tendons are involved. Physiotherapist may show you special exercises for each type of nerve disorder.

Effect of acupuncture, acupressure, TENS (Trans Cutaneous Nerve Stimulation) may be debatable. Certain ointments like capsaicin may temporarily relieve tingling, burning sensations.

Prevention of Arm Numbness

The following may help to prevent arm and hand numbness:

  • avoid putting the arm over the chair back to prevent permanent injury of brachial plexus
  • avoid sleeping with the hand under the head, or with arms on the pillow
  • avoid use of mechanical screwdrivers
  • don’t rest your elbows on the desk for long periods of time
  • wear warm gloves at low temperatures
Further Reading:

Head, Face and Neck Numbness
Numb Feet and Toes
Causes of Tingling and Numbness

References:

  1. Brachial plexus (bartleby.com)
  2. Anatomy of the arm (frca.co.uk)