what causes numbness and tingling in arms and hands?

You may be familiar with the numbness or “pins and needles” feeling from staying seated in one position too long, or from holding your arm at an uncomfortable angle for a period of time. But when this numbness or tingling does not go away quickly, or has no obvious cause, it may be a sign of nerve damage or other medical problems.

causes of numbness

Many cases of numbness and tingling in the arms and hands are a result of a nerve injury or accident. These injuries may make you a candidate for surgical nerve repair to relieve the numbness, pain or other symptoms that affect your quality of life. These injuries could be due to:

• Traumatic event or accident
• Prior surgery
• Prior injury from a fractured or broken bone
• Long-term compression (often due to overuse)

what types of nerve injuries could cause numbness and tingling?

There are seven nerves that control sensation to the hands and arms:

• Axillary nerve injury can cause numbness and weakness in the outer shoulder. This could be due to improper use of crutches or cast placement, a traumatic injury or event (like a car accident), a bone fracture of the upper humerus, a dislocated shoulder, or prior shoulder arthoscropy (surgery to repair joint problems).
• Brachial plexus nerve injury can cause a limp arm, pain and numbness in the shoulder. This could be due to a traumatic accident or injury, or Erb’s palsy (which can occur during childbirth, or due to an accident later in life).
• Musculocutaneous nerve injury can cause pain, tingling or numbness of the outside of the forearm. It can happen due to overusing the biceps, a traumatic injury to the shoulder or arm or surgical injury (usually during surgery on the humerus bone).
• Median nerve injury can cause numbness, pain, tingling or weakness of the forearm, wrist or hand. This could be due to a traumatic injury or entrapment of the nerve near the wrist. This entrapment is called carpal tunnel syndrome and is common among people who use repetitive wrist or hand motions.
• Ulnar nerve injury can cause numbness, pain, tingling or weakness in the hand, inability to move your fingers, and weakness when flexing the hand. Common causes include entrapment of the nerve around the elbow or the palm, an injury such as a glass cut or car accident, or long-term compression (such as from bicycle handlebars or using a computer mouse for long hours).
• Radial nerve injury can cause numbness, tingling or weakness in the wrist, fingers and thumb. This can happen due to entrapment of the nerve (carpal tunnel syndrome), traumatic injury or accident (such as from power tools or a car accident), or breaks in the humerus bone.
• Digital nerve injury can cause numbness, tingling or pain in the fingers. Causes include a cut or laceration to the fingers, or a traumatic injury.

other causes of numbness

Not all cases of numbness and tingling are a result of nerve damage. Chronic loss of sensation in the arms and hands is also called peripheral neuropathy, and its cause could be a wide range of medical conditions. Peripheral neuropathy is different than a nerve injury, and it cannot be fixed with surgical nerve repair.

• Up to 50% of people with diabetes may feel numbness, tingling or pain in their hands, arms, legs and feet. This happens when diabetes damages the blood vessels that support nerves, leading to peripheral neuropathy.
• Multiple sclerosis (MS). Loss of sensation in the arms, legs, face or body is often one of the first symptoms of MS, since the disease causes the immune system to attack the fatty tissue that protects your nerve cells.
• Vitamin deficiency. A vitamin B₁₂ deficiency is a common cause of numb hands and feet; other vitamin deficiencies can also affect nerve function. Your doctor can perform tests to determine which, if any, vitamins you may be lacking.
• People with fibromyalgia, a chronic fatigue disorder, may experience numb hands. Other symptoms of the disorder often include musculoskeletal pain, along with sleep, memory and mood issues.
• Herniated disc. A herniated, slipped or bulged disc is an injury to the tissue that cushions and connects the vertebrae. In some cases, it can cause numbness and/or pain in the hands and shoulders, or the lower body, depending on the location of the injured disc.
• Cancer treatments. Chemotherapy, radiotherapy and surgery can lead to hypersensitivitiy (tingling, burning and electrical sensations) and/or hyposensitivity (numbness and muscle weakness). It can occur in up to 40% of cancer patients.

how can i regain feeling in my hands and arms?

Most people experience numb or tingling hands and arms from time to time. But when it affects your quality of life, it’s time to seek help. If you suspect your symptoms are caused by nerve damage, we’ve created a guide to help you locate a doctor who treats nerve problems.