Muscle Spasm: Neck, Back and Leg Spasms Explained

What happens during a muscle spasm

Muscles contract when nerves send them a signal and relax when the signal stops. In a spasm, the nerve keeps firing or the muscle becomes overexcitable, so it stays contracted. The muscle feels hard and knotted, blood flow to it drops, and waste products build up, which causes the pain.

There are two broad kinds:

• Cramp-type spasms: brief, intense contractions, often in the calf or foot, that release within minutes. See muscle spasms for the many causes of cramps and twitches, including in the hands and fingers.
• Protective (guarding) spasms: muscles tighten around a strained or irritated area to stop it moving. This is what usually happens in the neck and lower back, and it can last days.

Muscle spasm vs cramp vs strain

Neck muscle spasm symptoms

• sudden pain and stiffness in the side or back of the neck, often on waking
• a tight, hard knot you can feel in the muscle
• difficulty turning your head to one side or looking down
• pain spreading to the shoulder, upper back or base of the skull
• tension-type headache starting at the back of the head

A neck that is pulled and twisted to one side is called a wry neck or torticollis. In adults it is usually from a muscle spasm and resolves within a week. A neck that repeatedly twists or jerks involuntarily over months may be cervical dystonia, a neurological condition.

Common causes of neck spasm

• sleeping in an awkward position or on too many pillows
• long periods looking down at a phone, laptop or desk ("tech neck")
• carrying heavy bags on one shoulder
• whiplash or sports injuries
• stress, which tightens the trapezius and neck muscles
• a pinched nerve or arthritis in the neck

Back muscle spasm symptoms

• sudden, severe pain in the lower back, often after lifting, bending or twisting
• muscles along the spine that feel rock-hard
• difficulty standing up straight, bending or getting out of a chair
• pain that eases when lying still and returns with movement

Most back spasms come from a minor strain of the back muscles or ligaments. A spasm can also be the body's response to a herniated disc or facet joint irritation. Pain spreading below the knee with numbness or tingling suggests a pinched nerve.

Other common sites

• Calves and feet: night cramps and exercise cramps. See leg cramps.
• Thighs: hamstring and quadriceps cramps during sport.
• Abdomen: "stitches" during running.
• Chest wall: intercostal muscle spasm after coughing or strain, which hurts more with breathing. Chest pain should always be assessed if heart disease is possible.

Causes and risk factors

• muscle fatigue, overuse and unaccustomed activity
• poor posture and staying in one position
• dehydration and heavy sweating
• low potassium, calcium or magnesium
• stress and poor sleep
• older age, pregnancy, diabetes and thyroid disease
• medicines such as diuretics and statins
• nerve and spine problems
• rarely, muscle inflammation (myositis) or neurological disease

Diagnosis

Most muscle spasms are diagnosed from your description and an examination of posture, movement, tender muscles, reflexes, strength and sensation. Tests are needed only when there are warning signs or symptoms do not improve:

• Blood tests for minerals, thyroid, kidney function and muscle enzymes (CK)
• X-ray or MRI if a fracture, disc problem or nerve compression is suspected
• Nerve studies if there is numbness or weakness

Treatment

First 48 hours

• Keep moving gently. Bed rest makes neck and back spasms last longer. Walk short distances and change position often.
• Heat: a warm shower, heat pack or heating pad for 15 to 20 minutes relaxes muscles. Some people prefer ice in the first day.
• Pain relief: ibuprofen or naproxen reduce pain and inflammation (avoid if you have stomach ulcers, kidney disease or are on blood thinners), or acetaminophen (paracetamol). Follow the label dose.
• Gentle stretching within comfort, such as slowly tilting the ear toward the shoulder for a neck spasm, or knee-to-chest stretches for the lower back.

If it persists

• Physical therapy: stretching, strengthening, posture correction and manual therapy.
• Massage: helps release knots and improves short-term pain.
• Muscle relaxant medicines: sometimes prescribed for a few days for severe acute back spasm. They cause drowsiness and are not for long-term use.
• Botulinum toxin injections for dystonia.
• Treating the cause: correcting mineral levels, adjusting medicines, or treating a disc problem.

Preventing repeat spasms

• Set your screen at eye level and take breaks every 30 to 60 minutes.
• Use one supportive pillow that keeps your neck in line with your spine.
• Lift with your legs, keep loads close to your body, and avoid twisting while lifting.
• Strengthen core and back muscles, and stretch regularly.
• Stay hydrated and manage stress.

Frequently asked questions

What are the symptoms of a neck muscle spasm?

Typical symptoms are sudden neck pain and stiffness, a hard, tender knot in the muscle, difficulty turning the head, and pain spreading to the shoulder or base of the skull, sometimes with a headache. It often starts on waking or after a long period at a desk.

How long does a muscle spasm last?

A cramp lasts seconds to a few minutes. A neck or back spasm from a strain usually improves within a few days and settles within 1 to 2 weeks. See a doctor if it is not improving after 2 weeks or if warning signs develop.

Should I use heat or ice for a muscle spasm?

Heat usually works best because it relaxes tight muscle and improves blood flow. Ice can ease pain in the first 24 to 48 hours after an injury. Use either for 15 to 20 minutes at a time, with a cloth between the pack and your skin.

Can stress cause muscle spasms?

Yes. Stress tightens muscles, especially in the neck, shoulders and jaw, and can cause spasms, knots and tension headaches. Relaxation techniques, exercise, good sleep and regular breaks from desk work help reduce them.

What is the difference between a muscle spasm and a pulled muscle?

A spasm is the muscle tightening involuntarily. A pulled muscle (strain) is damage to the muscle fibers from overstretching. A strain often causes a spasm around it, so the two frequently occur together.