Trapezius Muscle

Overview

What is the trapezius muscle?

The trapezius is a large muscle in your back. It starts at the base of your neck and extends across your shoulders and down to the middle of your back. Providers call it the trapezius because of its shape. It looks like a trapezoid (a shape with four sides, two that are parallel). Some people call the trapezius the traps muscle.

The trapezius is responsible for posture and movement. It allows you to tilt your head up and down and turn your head all around. It also helps you stand up straight, twist your torso and shrug your shoulders or pull them back. The trapezius controls your scapula (shoulder blade) when you lift your arm or throw a ball.

Trapezius muscle strain is a common injury that happens when you stretch the muscle too far. In severe injuries, the muscle can tear. To avoid injury and keep your traps strong, you should warm up before exercise and focus on staying healthy overall.

Function

What is the purpose of the trapezius?

This large muscle helps you move your body and have good posture. Healthcare providers divide the trapezius into three areas. Each area helps you with a specific kind of movement. Together, the three parts of the trapezius help you move your head, stand up straight, bend or twist your torso and raise your arms. The areas of the trapezius are:

Upper trapezius: This is the smallest section of the trapezius. It starts at the base of your neck and extends just across the tops of your shoulders. It helps you:

  • Lift your arms.
  • Rotate, extend, turn and tilt your neck and head.
  • Shrug your shoulders.

Middle trapezius: This area of the muscle sits just below the upper trapezius. It goes all across your shoulders. The middle traps is responsible for:

  • Helping you pull your shoulders back and extend your arms behind you.
  • Stabilizing your shoulders when you move your arms.

Lower trapezius: The lower traps starts around your shoulder blades and come down into a “V” shape in the middle of your back. This part of the trapezius:

  • Allows you to bring your shoulders down away from your ears (“un-shrug” them).
  • Stabilizes your spine during certain movements, including twisting and bending.

Anatomy

Where is the trapezius?

The trapezius is the most superficial muscle in the back, which means it’s just under the skin. It extends from a point at the base of the neck and goes across both shoulders and down your back. It ends at a point in the middle of your back.

The trapezius muscles attach to several bones, including the spine, scapulae (shoulder blades), ribs and clavicle (collarbone). A cranial nerve (a nerve that originates from the brain) controls the trapezius.

What does the trapezius muscle look like?

The traps is a type of muscle called skeletal muscle. Its shape is similar to a kite. As part of your musculoskeletal system, this muscle provides a framework for bones and other soft tissues. Many individual fibers make up skeletal muscles. These fibers bundle together to create a striated, or striped, appearance.

Conditions and Disorders

What conditions and disorders affect the trapezius?

Injuries that affect how the traps works include:

  • Muscle strains: Due to an accident, rigorous exercise or overuse, the traps muscle can stretch too far or tear. This common injury can lead to muscle cramps or muscle spasms. Back strains and back spasms can affect the traps muscles or any muscles in the lower back.
  • Nerve damage: If the nerve that controls the trapezius gets injured, the trapezius muscle may not work as it should. Though uncommon, this type of injury can result from neck surgery (such as surgery to remove a tumor). Nerve damage can cause muscle weakness. In severe cases, the entire traps muscle can be paralyzed.
  • Tightness and pain: Poor posture, such as sitting at a desk with hunched shoulders for long periods of time, can cause tightness in the traps. People who sit at a computer for several hours a day have a higher risk of chronic pain in the neck and shoulders. Headaches can result from tension in the shoulders, especially if tight muscles put pressure on the nerve that controls the trapezius.

What are some common signs or symptoms of conditions affecting the trapezius?

An injury to the trapezius can cause:

  • Limited mobility, decreased range of motion or muscle weakness (you may not be able to shrug your shoulders or raise your arm).
  • Neck and shoulder pain and stiffness.
  • Pain between the shoulder blades.
  • Swelling, bruising or tenderness in your shoulders, neck or back.
  • Trapezius muscle pain.

What are some common tests to check the health of the trapezius?

Providers can usually diagnose trapezius muscle problems during a physical examination. Depending on your symptoms, your provider may order an MRI or other imaging study to look for damage to the muscle.

If your provider suspects nerve damage, you may need an electromyogram (EMG). This test measures how the nerves and muscles work.

What are some common treatments for trapezius injuries?

Depending on the location and severity of the injury, your provider may recommend:

  • Acupuncture: Dry needling and acupuncture can relieve pain and tightness in the trapezius.
  • Massage therapy: Massage can help you recover from or prevent a traps injury by increasing flexibility and relaxing tight muscles.
  • Rest: Minor muscle strains and tears can heal with rest. You may need to avoid certain activities, such as bending, lifting your arms or shrugging your shoulders. Drink plenty of water to keep your muscles hydrated.
  • Surgery: Severe muscle tears may need surgical repair. Your provider uses stitches to sew torn muscles so they can heal properly.

Care

How can I keep my trapezius healthy?

To keep your muscles strong, you should focus on staying healthy overall. To avoid problems with your trapezius, you should:

  • Exercise and stay flexible: Many different shoulder stretches and traps exercises can improve range of motion, strengthen muscles or relax tight muscles. Yoga, Pilates and other gentle exercises can help keep muscles strong and flexible. When you’re exercising, don’t overdo it. Stop if you feel pain.
  • Maintain a healthy weight: Carrying extra pounds increases your risk of muscle strain. Talk to your provider about the most appropriate weight for your body and lifestyle.
  • Warm up before you exercise: Take time to stretch and warm up properly before you exercise. You’re less likely to injure warm, flexible muscles.

Frequently Asked Questions

When should I call my doctor about my trapezius?

If you have trapezius pain or back pain that doesn’t getter better in a day or two, call your provider. Get help right away if you have severe muscle weakness or difficulty moving your shoulders, lifting your arms or moving your head. These could be signs of nerve damage that can lead to paralysis of the traps muscle.

A note from Cleveland Clinic

Your trapezius muscle plays an essential role in helping you move your head, neck, arms, shoulders and torso. It also stabilizes your spine so you can stand up straight. You can keep this large muscle strong by staying active and maintaining a healthy weight. To avoid an injury, take time to warm up before you exercise. Focus on good posture. Stretch your shoulders and back regularly to keep your trapezius muscles flexible.

Last reviewed by a Cleveland Clinic medical professional on 06/03/2021.

References

  • Brandt M, Sundstrup E, Jakobsen MD, Jay K, Colado JC, Wang Y, Zebis MK, Andersen LL. Association between Neck/Shoulder Pain and Trapezius Muscle Tenderness in Office Workers. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3985383/) Pain Res Treat. 2014;2014:352735. Accessed 5/10/2021.
  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Healthy Muscles Matter. (https://www.niams.nih.gov/health-topics/kids/healthy-muscles) Accessed 5/10/2021.
  • Ourieff J, Scheckel B, Agarwal A. Anatomy, Back, Trapezius. (https://www.ncbi.nlm.nih.gov/books/NBK518994/) [Updated 2020 Aug 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Accessed 5/11/2021.

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