photo of ribbing stiff hand
In This Article

Spasticity is a condition that causes your muscles to stiffen, tighten, and contract. It happens involuntarily, which means you don’t have control over it. Spasticity typically happens because of damage to your brain, spinal cord, or the nerves that carry signals to your muscles.

What Are the Symptoms of Spasticity?

When you have spasticity, your muscles may feel heavy, freeze in a certain position, or spasm – suddenly stiffen and cause a jerk or kick.

You may have trouble bending muscles that are straight (extensor spasticity) or straightening muscles that are bent (flexor spasticity).

Other symptoms include:

  • Abnormal posture
  • Shoulders, arms, wrists, or fingers bent at unusual angles
  • Repetitive jerky motions
  • Crossing legs in a scissor motion
  • Pain or deformity in the part of the body with spasticity
  • Over exaggeration of natural reflexes
  • Tightness in joints
  • Muscle spasms

Spasticity can happen anywhere in your body, but it’s most common in leg muscles. It can also affect the muscles that control speech, making it harder to talk.

Over time, untreated spasticity can lead to permanent contracting and shrinking of muscles. This could lock your joints into one position.

What Causes Spasticity?

Your brain sends signals to your muscles through nerves. Certain conditions of the central nervous system or damage to parts of your brain and spinal cord can disrupt this communication and keep it from working the way it should. Your muscles either don’t get the message they need, or the message is scrambled.

Damage to your nervous system can happen several ways, including certain conditions you’re born with. Some of the causes of spasticity include:

  • Adrenoleukodystrophy (disorder that prevents the breakdown of certain fats)
  • Amyotrophic lateral sclerosis (ALS)
  • Brain damage caused by lack of oxygen
  • Cerebral palsy
  • Head injury
  • Multiple sclerosis
  • Illnesses that damage the brain and nervous system over time (neurodegenerative illness)
  • Phenylketonuria (disorder in which the body can't break down the amino acid phenylalanine)
  • Spinal cord injury
  • Stroke

It can also be brought on by certain triggers, such as:

  • Sudden movement
  • Position changes
  • Fatigue
  • Extreme temperatures
  • Humidity
  • Infection
  • Stress
  • Tight clothing

The severity of your spasticity depends on what’s causing it.

Living With Spasticity

Spasticity can make it harder to walk, speak, and do other daily activities. But it can be helpful sometimes. Stiff muscles make it easier to brace yourself when standing or moving from one spot to another. Contracted finger muscles may help you pick up objects. Spasticity may also be a sign that something else is going on with your body, such as a urinary tract infection or pressure sore.

If your spasticity is painful or disrupts your daily living, you doctor can work with you to help treat it. through a combination of exercises, stretches, medicine, and in some cases, surgery.

By learning to avoid spasticity triggers, you may find ways to function fine with spasticity. As you age, your nerves conduct signals more slowly, so spasticity may naturally decrease as that happens. If you notice an uptick in your spasticity, it could be a sign of a problem, so talk to your doctor.

Show Sources

Photo Credit: krisanapong detraphiphat / Getty Images


National Multiple Sclerosis Society: “Spasticity.”

American Association of Neurological Surgeons: “Spasticity.”

Penn Medicine: “Spasticity.”

Weill Cornell Brain and Spine Center: “Spasticity.”

Johns Hopkins Medicine: “Spasticity.”

University of Washington Northwest Regional Spinal Cord Injury System: “Spasticity and Spinal Cord Injury.”