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Muscle atrophy

Show Alternative Names
Muscle wasting
Wasting
Atrophy of the muscles

Muscle atrophy is the wasting (thinning) or loss of muscle tissue.

Causes

There are three types of muscle atrophy: physiologic, pathologic, and neurogenic.

Physiologic atrophy is caused by not using the muscles enough. This type of atrophy can often be reversed with exercise and better nutrition. People who are most affected are those who:

  • Have seated jobs, health problems that limit movement, or decreased activity levels
  • Are bedridden
  • Cannot move their limbs because of stroke or other brain disease
  • Are in a place that lacks gravity, such as during space flights

Pathologic atrophy is seen with aging, starvation, and diseases such as Cushing disease (because of taking too much medicines called corticosteroids or having overactive adrenal glands).

Neurogenic atrophy is the most severe type of muscle atrophy. It can be from an injury to, or disease of a nerve that connects to the muscle. This type of muscle atrophy tends to occur more suddenly than physiologic atrophy.

Examples of diseases affecting the nerves that control muscles:

  • Amyotrophic lateral sclerosis (ALS, or Lou Gehrig disease)
  • Damage to a single nerve, such as carpal tunnel syndrome
  • Guillain-Barré syndrome
  • Nerve damage caused by injury, diabetes, toxins, or alcohol
  • Polio (poliomyelitis)
  • Spinal cord injury

Although people can adapt to muscle atrophy, even minor muscle atrophy causes some loss of movement or strength.

Skeletal muscle - Animation

Regular workouts that include resistance training, such as weight lifting, cause the muscle fibers of skeletal muscle to increase in size and improve overall body tone. Skeletal muscle is a well-organized body tissue, composed in a complex array of smaller and smaller structures. Let’s take a look at a cut-section to see how skeletal muscle is organized. Each skeletal muscle is composed of many units called muscle fascicles. Notice that the fascicles are bound together by a type of connective tissue, which is called fascia. And from that fascicle, we can pull away smaller organizational units called muscle fibers. And from that muscle fiber, we can pull away even smaller strands called myofibrils. Here you can see the myofibrils move as the muscle is contracting. It’s the interaction of these myofibrils as they slide and pull along side each other that gives skeletal muscle its functional ability to do work and move things. Putting it all back together, myofibrils compose muscle fibers, that make-up muscle fascicles, which are grouped together within a skeletal muscle.

Other causes of muscle atrophy may include:

Home Care

An exercise program may help treat muscle atrophy. Exercises may include ones done in a swimming pool to reduce the muscle workload, and other types of rehabilitation. Your health care provider can tell you more about this.

People who cannot actively move one or more joints can do exercises using braces or splints.

When to Contact a Medical Professional

Contact your provider for an appointment if you have unexplained or long-term muscle loss. You can often see this when you compare one hand, arm, or leg to the other.

What to Expect at Your Office Visit

Your provider will perform a physical examination and ask about your medical history and symptoms, including:

  • When did the muscle atrophy begin?
  • Is it getting worse?
  • What other symptoms do you have?

The provider will look at your arms and legs and measure muscle size. This may help determine which nerves are affected.

Tests that may be performed include:

Treatment may include physical therapy, ultrasound therapy and, in some cases, surgery to correct a contracture.

Review Date: 12/31/2023

Reviewed By

Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW. Musculoskeletal system. In: Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW, eds. Seidel's Guide to Physical Examination. 10th ed. St Louis, MO: Elsevier; 2023:chap 22.

Selcen D. Muscle diseases. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 389.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Skeletal muscle

Skeletal muscle

Animation

Active vs. inactive muscle - Illustration Thumbnail

Active vs. inactive muscle

People may lose 20 to 40 percent of their muscle and, along with it, their strength as they age. Scientists have found that a major reason people lose muscle is because they stop doing everyday activities that use muscle power, not just because they grow older.

Illustration

Muscular atrophy - Illustration Thumbnail

Muscular atrophy

Muscular atrophy is the decrease in size and wasting of muscle tissue. Muscles that lose their nerve supply can atrophy and simply waste away.

Illustration

 
Skeletal muscle

Skeletal muscle

Animation

 
Active vs. inactive muscle - Illustration Thumbnail

Active vs. inactive muscle

People may lose 20 to 40 percent of their muscle and, along with it, their strength as they age. Scientists have found that a major reason people lose muscle is because they stop doing everyday activities that use muscle power, not just because they grow older.

Illustration

Muscular atrophy - Illustration Thumbnail

Muscular atrophy

Muscular atrophy is the decrease in size and wasting of muscle tissue. Muscles that lose their nerve supply can atrophy and simply waste away.

Illustration

 
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Skeletal muscle - Animation

Regular workouts that include resistance training, such as weight lifting, cause the muscle fibers of skeletal muscle to increase in size and improve overall body tone.

Skeletal muscle is a well-organized body tissue, composed in a complex array of smaller and smaller structures. Let’s take a look at a cut-section to see how skeletal muscle is organized.

Each skeletal muscle is composed of many units called muscle fascicles. Notice that the fascicles are bound together by a type of connective tissue, which is called fascia. And from that fascicle, we can pull away smaller organizational units called muscle fibers.

And from that muscle fiber, we can pull away even smaller strands called myofibrils. Here you can see the myofibrils move as the muscle is contracting. It’s the interaction of these myofibrils as they slide and pull along side each other that gives skeletal muscle its functional ability to do work and move things.

Putting it all back together, myofibrils compose muscle fibers, that make-up muscle fascicles, which are grouped together within a skeletal muscle.

 

Skeletal muscle - Animation

Regular workouts that include resistance training, such as weight lifting, cause the muscle fibers of skeletal muscle to increase in size and improve overall body tone.

Skeletal muscle is a well-organized body tissue, composed in a complex array of smaller and smaller structures. Let’s take a look at a cut-section to see how skeletal muscle is organized.

Each skeletal muscle is composed of many units called muscle fascicles. Notice that the fascicles are bound together by a type of connective tissue, which is called fascia. And from that fascicle, we can pull away smaller organizational units called muscle fibers.

And from that muscle fiber, we can pull away even smaller strands called myofibrils. Here you can see the myofibrils move as the muscle is contracting. It’s the interaction of these myofibrils as they slide and pull along side each other that gives skeletal muscle its functional ability to do work and move things.

Putting it all back together, myofibrils compose muscle fibers, that make-up muscle fascicles, which are grouped together within a skeletal muscle.

 
 
 
 

 

 
 
 
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