National Associaltion of Myofascial Trigger Point Therapists - Symptom Checker

Pectoralis Major and Subclavius
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This is the technical name of the muscle being described.  This name may be used to find additional information in any medical resource.

Pectoralis Major and Subclavius

A group of muscles generally denotes muscles of the same function and may share a common attachment point. Torso muscles
Muscle function, in this definition, is what the muscle could do if it was to contract by itself with the body in anatomical position.  This is a general definition of muscle function.  For more information on how muscles work together on the body please refer to a physiology or functional anatomy text.

When the thorax is fixed, the pectoralis major acts to adduct (bring closer to the body) and medially rotate the humerus.

If you are experiencing chest pain and symptoms of a heart attack it is imperative that you seek medical attention immediately.

A description of where a Myofascial Trigger Point may produce pain in the body.  This area is generally located away from the trigger point.

Pectoralis Major has three distinct fiber orientations and different pain patterns that arise from each of the fibers – clavicular, sternal, and costal. 
The clavicular fibers refer pain to the anterior (front) shoulder as well as locally over the area of the clavicular fibers themselves.

Pain from the sternal fibers refer pain locally over the anterior chest, as well as some spill-over pain down the arm, which focuses over the medial (inside) elbow, and when very intense, in the ulnar aspect (pinky side) of the hand.

The costal fibers cause breast tenderness, with hypersensitivity of the nipple, intolerance to clothing, as well as breast pain. 

“More medially, a TrP associated with somatovisceral cardiac arrhythmias is located on the right side between the fifth and sixth ribs, just below the point where the lower border of the fifth rib crosses a vertical line that lies midway between the margin of the sternum and the nipple.  This TrP has been observed only on the right side, except in situs inversus.  The spot tenderness of this trigger point is associated with ectopic cardiac rhythms, but not with any pain complaint.  There may be nearby tender points over or between adjacent ribs that are not pertinent to cardiac arrhythmia.”

The subclavius can refer pain into the upper extremity on the same side by traveling across the front of the shoulder, and down the front of the arm and along the radial (thumb side) of the forearm.  The pain skips over the elbow and reappears in the radial half of the hand, projecting pain over the thumb, index, and middle fingers.

A description of the symptoms a person may experience with trigger points in the muscle being described.

A person with TrPs arising from the pectoralis major tends to be
aware of secondary interscapular (area between the scapula and the spine) pain as well their related pain from the pectoralis major.  When the pectoralis muscle shortens it places tension in the opposing scapular adductors, such as the middle trapezius and rhomboids, and causes these muscles to refer their interscapular pain.  This same effect occurs when the pectoralis muscle shortens and pulls on the clavicle.  This places tension on the clavicular division of the sternocleidomastiod (SCM) muscle, thus activating TrPs.

Pain is commonly referred widely over the precordium, if on the left side, and down the arm and into the 4th and 5th digits.  A feeling of chest constriction may also occur, but it may be thought to be angina pectoris.  Intermittent intense chest pain, with upper limb activity, and if severe, will occur during rest. 

Pain in the breast and nipple can make a bra or t-shirt extremely uncomfortable.

A person who presents with a pain or tenderness in their breast and nipple, especially females, may be relieved to realize that their pain may be from active trigger points, and not from cancer, for which they have an unexpressive concern.

Subclavius TrPs can contribute to shortening that contributes to a vascular thoracic outlet syndrome.


 A list of possible diseases that fit the information derived from examination of a patient.

  1. Angina pectoris.
  2. Tear of the muscle belly.
  3. Bicipital tendonitis.
  4. Supraspinatus tendonitis.
  5. Subacromial bursitis.
  6. Medial epicondylitis.
  7. Lateral epicondylitis.
  8. C5-C6 radiculopathy.
  9. C7-C8 radiculopathy.
  10.  Intercostal neuritis or radiculopathy.
  11.  Irritation of the bronchi, pleura, or esophagus.
  12.  Hiatal hernia with reflux.
  13.  Distension of the stomach by gas.
  14.  Mediastinal emphysema.
  15.  Gaseous distension of the splenic flexure of the colon.
  16.  Lung cancer.
  17.  Pain may be confused with coronary insufficiency.
  18.  Costochondritis.
  19.  Tietze’s syndrome.
  20.  Hypersensitive xiphoid syndrome.
  21.  Precordial catch syndrome.

A list of activities or positions that may either CAUSE a trigger point to manifest or PROLONG a pain condition respectively.

  1. Pectoralis major TrPs are perpetuated by a round shouldered posture (slouching).
  2. Arm adduction (bringing the arms closer to the body), as when using manual hedge clippers.
  3. Sustained lifting in a fixed position, as when using a power saw.
  4. Immobilization of the arm in an adducted position, as with the arm in a sling or cast.

A corrective action is usually a modification of daily routine which will reduce stress on the affected muscle(s) in a person with myofascial trigger points.

  1. Slouched posture should be recognized and avoided.
  2. When sleeping a person should avoid sleeping with the arms crossed over the chest.
  3. When sleeping on the back a person should tuck their pillow between the neck and shoulders so that no aspect of the pillow is under the upper body/shoulders.  This will allow the shoulders to relax and the scapulas to retract.
  4. When sleeping on the side a person should support the uppermost arm using a pillow so the arm does not hang down and shorten the pectoralis muscle.

References : 
Simons DG, Travell JG, Simons LS, Myofascial Pain and Dysfunction: The Trigger Point Manual, vol 1, 2nd Ed. Baltimore: Williams and Wilkins, 1999.

Travell JG, Simons DG, Myofascial Pain and Dysfunction, vol 2. Baltimore: Williams & Wilkins, 1992.

This information is not intended to diagnose, treat, or cure any disease.  A proper diagnosis should be sought from a licensed health care provider.