Muscle Cramps
(of Skeletal Muscles)
Medical Author: Daniel Gornel, MD, MPH
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
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Muscle Cramps: a Real Pain
Medical Author: Melissa Stöppler, MD
Medical Editor: Barbara K. Hecht, PhD
Anyone who has experienced a muscle cramp (charley horse) can attest to the fact that it can
be quite painful. Muscle cramps occur when muscles involuntarily contract and
cannot relax.
The skeletal muscles (those over which we have voluntary
control) are most prone to cramping. The skeletal muscles in the calf, thigh,
and arch of the foot
are most notorious sites of cramps.
Cramps can be perceived as mild twitches or may be excruciatingly painful.
Typically, cramps cause an abrupt, intense pain in the involved muscle.
Often a muscle that is cramping feels harder than normal to the touch or may
even show visible signs of twitching. Most cramps resolve spontaneously within a
few seconds to minutes.
It is not known exactly why muscle cramps develop. Insufficient stretching
before exercise, exercising in the heat, and muscle fatigue may all play a role
in their causation. Imbalances in the levels of electrolytes (sodium, potassium,
chloride, calcium and phosphate) in the blood
can also lead to muscle cramps.
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What are muscle cramps?
When we use the muscles that can voluntarily be controlled, such as
those of our arms and legs, they alternately contract and relax as we
move our limbs. Muscles that support our head, neck, and trunk
contract similarly in a synchronized fashion to maintain our
posture. A muscle (or even a few fibers of a muscle) that
involuntarily (without consciously willing it) contracts is called
a "spasm." If the spasm is forceful and sustained, it becomes a
cramp. A muscle cramp is thus defined as an involuntarily and
forcibly contracted muscle that does not relax. This causes a visible or palpable hardening of the involved muscle.
Muscle cramps can last anywhere from a few seconds to a quarter of an
hour or occasionally longer. It is not uncommon for a cramp to
recur multiple times until it finally goes away. The cramp may
involve a part of a muscle, the entire muscle, or several muscles
that usually act together, such as those that flex adjacent fingers.
Some cramps involve the simultaneous contraction of muscles that
ordinarily move body parts in opposite directions.
Cramps are extremely common. Almost everyone (one estimate is about
95%) experiences a cramp at some time in their life. Cramps are
common in adults and become increasingly frequent with aging.
However, children also experience cramps.
Any of the muscles that are under our voluntary control (skeletal
muscles) can cramp. Cramps of the extremities, especially the legs
and feet, and most particularly the calf (the classic "charley
horse"), are very common. Involuntary muscles of the various organs
(uterus, blood vessel wall, intestinal tract, bile and urine
passages, bronchial tree, etc.) are also subject to cramps. Cramps
of the involuntary muscles will not be further considered in this
review. This article focuses on cramps of skeletal muscle.
Next: What are the types and causes of muscle cramps? »
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From the Doctors at MedicineNet.com  |
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Last Editorial Review: 2/1/2008