Table of ContentsView AllTable of ContentsAnatomyFunctionAssociated ConditionsRehabilitationFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Associated Conditions
Rehabilitation
Frequently Asked Questions
The sternocleidomastoids (SCMs) are superficially located neck muscles that play an important role in tilting your head and turning your neck, as well as other movements. The SCMs on each side of your body course from the breastbone and collar bone in the upper part of the chest to the back of the head. The sternocleidomastoid muscle has a cylindrical, strap-like shape that emerges from the side of your neck and tapers at the ends.
PeopleImages / Getty Images
Anatomy of the SCM
The SCM has two heads. One originates from the collarbone/clavicle and the other from the breastbone/manubrium.
Origins of the SCM:
SCM insertions:
Sternocleidomastoid Function
The SCN can produce several different neck movements. One side can contract, or both sides can contract.
When just one SCM muscle contracts:
When both SCM muscles contract, the movements can include:
Simultaneous bilateral SCM muscle contraction also plays a role in the breathing process. In this case, it lifts up the breastbone and the area of the collarbones that are nearest to the midline of the body.
The SCM is part of a group of muscles known as the anterolateral neck flexors. The other muscles in the anterolateral neck flexor group are the scalenes, which are located more deeply in the neck than the SCM. The scalenes are synergist (helper) muscles to the SCM. They assist the SCM in turning and tilting both the head and neck.
The SCM becomes chronically shortened in cases of torticollis.Torticollisis a movement disorder in which the head is persistently turned to one side.Treatment of a shortened SCM involves gentle stretching of a tight SCM muscle to lengthen it to a normal shape.
An impairment or injury to the spinal accessory nerve can cause weakness or paralysis to the SCM. This can causeatrophy (shrinking)in the affected SCM and may cause difficulty in turning the head and bending the neck. Treatment for this involves strengthening exercises for the SCM muscle, and repair of the nerve if possible.
Sternocleidomastoid Pain: Exploring Potential Causes and Relief Strategies
Working with a physical therapist can be a useful modality to strengthen the SCM if it has been injured or weakened.
Exercises for the SCM may include:
By working to keep good posture and gently stretch and strengthen the SCM and other muscles around your neck, you can experience improvement of symptoms associated with the SCN.
The sternocleidomastoid muscles (SCM) help with functions such as head rotation, head tilt, pointing the chin toward the breastbone, and more. Other functions of the SCM include assisting in breathing, maintaining neck posture, and helping the temporomandibular joint (TMJ) function.
Synergist muscles help other muscles perform one or more functions. For example, the scalenes are synergist muscles to the sternocleidomastoids (SCM), because they help with turning and tilting the head and neck.
2 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus, U.S. National Library of Medicine.Torticollis.Bordoni B, Varacallo M.Anatomy, head and neck, sternocleidomastoid muscle. StatPearls.Additional ReadingKapandji, I.A., “The Physiology of the Joints”. Fifth Edition. Churchill Livingstone. English Edition. New York.Kendall, Florence Peterson, McCreary, Elizabeth Kendall, and Provance, Patricia Geise. Muscles Testing and Function with Posture and Pain. 3rd. Baltimore, Maryland: Williams & WilkinsMoore, Keith, L., Dalley, Arthur, F. Clinically Oriented Anatomy. 5th Edition. Lippincott, Williams and Wilkins.
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus, U.S. National Library of Medicine.Torticollis.Bordoni B, Varacallo M.Anatomy, head and neck, sternocleidomastoid muscle. StatPearls.Additional ReadingKapandji, I.A., “The Physiology of the Joints”. Fifth Edition. Churchill Livingstone. English Edition. New York.Kendall, Florence Peterson, McCreary, Elizabeth Kendall, and Provance, Patricia Geise. Muscles Testing and Function with Posture and Pain. 3rd. Baltimore, Maryland: Williams & WilkinsMoore, Keith, L., Dalley, Arthur, F. Clinically Oriented Anatomy. 5th Edition. Lippincott, Williams and Wilkins.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus, U.S. National Library of Medicine.Torticollis.Bordoni B, Varacallo M.Anatomy, head and neck, sternocleidomastoid muscle. StatPearls.
MedlinePlus, U.S. National Library of Medicine.Torticollis.
Bordoni B, Varacallo M.Anatomy, head and neck, sternocleidomastoid muscle. StatPearls.
Kapandji, I.A., “The Physiology of the Joints”. Fifth Edition. Churchill Livingstone. English Edition. New York.Kendall, Florence Peterson, McCreary, Elizabeth Kendall, and Provance, Patricia Geise. Muscles Testing and Function with Posture and Pain. 3rd. Baltimore, Maryland: Williams & WilkinsMoore, Keith, L., Dalley, Arthur, F. Clinically Oriented Anatomy. 5th Edition. Lippincott, Williams and Wilkins.
Kapandji, I.A., “The Physiology of the Joints”. Fifth Edition. Churchill Livingstone. English Edition. New York.
Kendall, Florence Peterson, McCreary, Elizabeth Kendall, and Provance, Patricia Geise. Muscles Testing and Function with Posture and Pain. 3rd. Baltimore, Maryland: Williams & Wilkins
Moore, Keith, L., Dalley, Arthur, F. Clinically Oriented Anatomy. 5th Edition. Lippincott, Williams and Wilkins.
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
