Numbness of the Hand: What Your Pattern of Numbness Means

Which fingers are numb? A pattern guide

The pattern of numbness is the single best clue to the cause.

Common causes

Carpal tunnel syndrome

Carpal tunnel syndrome is the most common cause of hand numbness. The median nerve is squeezed in a narrow tunnel at the wrist. Typical features:

• numbness and tingling in the thumb, index and middle fingers
• symptoms that wake you at night, relieved by shaking the hand
• worse with driving, holding a phone or prolonged gripping
• later, weakness and wasting of the muscle at the base of the thumb

Risk factors include repetitive wrist use, pregnancy, diabetes, hypothyroidism, rheumatoid arthritis and obesity.

Ulnar nerve compression

The ulnar nerve runs behind the elbow (the funny bone). Pressure from leaning on elbows or sleeping with elbows bent causes numbness in the ring and little fingers and clumsiness. See ulnar nerve compression.

Pinched nerve in the neck

Cervical radiculopathy from a slipped disc or arthritis causes neck pain spreading into the arm with numbness in a specific finger pattern. Turning or tilting the head can worsen symptoms.

Sleeping on your arm

Pressure on nerves while sleeping causes temporary numbness that resolves within minutes of moving. Prolonged pressure, especially after alcohol or sedatives, can injure the radial nerve and cause wrist drop that takes weeks to recover.

Body-wide causes

• Peripheral neuropathy: diabetes is the most common cause. Numbness usually starts in the feet before the hands.
• Vitamin B12 deficiency: numbness in hands and feet, fatigue, and balance problems. Common with metformin, acid-reducing medicines, vegan diets and pernicious anemia.
• Hypothyroidism: raises the risk of carpal tunnel syndrome.
• Alcohol and chemotherapy: damage nerves.
• Raynaud's phenomenon: fingers turn white, then blue, then red with numbness during cold or stress.
• Multiple sclerosis: episodes of numbness lasting days to weeks.
• Anxiety and hyperventilation: tingling of both hands and around the mouth during panic.

Left hand vs right hand numbness

Both sides share the same causes. Carpal tunnel is often worse in the dominant hand. Numbness of the left arm and hand together with chest pain, jaw pain or breathlessness can signal a heart attack. Sudden numbness of either hand with face or speech changes can signal a stroke.

How doctors find the cause

Your doctor will map which fingers are numb, check strength, reflexes and muscle bulk, and try provocation tests such as tapping over the wrist (Tinel's sign) or holding the wrists flexed for a minute (Phalen's test). Tests may include:

• Nerve conduction studies and EMG to confirm nerve compression and its severity
• Blood tests: blood sugar or HbA1c, B12, thyroid function, kidney function
• Ultrasound of the wrist or elbow nerves
• MRI of the neck if a nerve root is suspected

Treatment and home care

Carpal tunnel syndrome

• Wrist splints worn at night, keeping the wrist straight
• Avoiding prolonged wrist bending and taking breaks from gripping
• Steroid injection into the carpal tunnel
• Carpal tunnel release surgery for persistent or severe cases, especially with weakness

Ulnar nerve

• Avoid leaning on the elbow, use an elbow pad, and keep the elbow straighter at night (a towel wrapped loosely around it helps)
• Surgery to release or move the nerve if symptoms persist

Neck causes

Physical therapy, posture changes and pain relief help most people. Injections or surgery are reserved for persistent cases or weakness.

General tips

• Change position and shake out the hand when numbness starts.
• Set up your desk so wrists are neutral and elbows are not resting on hard edges.
• Manage diabetes and correct vitamin B12 deficiency.
• Keep hands warm if you have Raynaud's.

Frequently asked questions

Why does my hand go numb at night?

The most common reason is carpal tunnel syndrome, because wrists often bend during sleep, squeezing the median nerve. Sleeping with elbows bent can compress the ulnar nerve, and lying on your arm can press on nerves. A night wrist splint often helps.

Should I worry about numbness in my hand?

Brief numbness that goes away when you move is usually harmless. See a doctor for numbness lasting more than a few days, numbness with weakness, or numbness in both hands and feet. Seek emergency care for sudden one-sided numbness with face, speech or vision changes.

Can a pinched nerve in the neck cause hand numbness?

Yes. A pinched nerve root in the neck can cause numbness in specific fingers along with neck and arm pain. The finger pattern helps identify which nerve root is involved: thumb for C6, middle finger for C7, and little finger for C8.

What deficiency causes numbness in the hands?

Vitamin B12 deficiency is the most common, causing numbness and tingling in the hands and feet. Low vitamin B6, B1 (thiamine) and copper can also cause nerve problems. A blood test can check B12 levels.

Is left hand numbness a heart attack?

Left hand numbness alone is rarely a heart attack. But numbness or pain in the left arm and hand together with chest pain or pressure, breathlessness, sweating, nausea or jaw pain can be a heart attack. Call 911 or your local emergency number.