Muscle:Pectoralis Major: Difference between revisions

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'''Pectoralis major''' is a large, multi-sectioned muscle of the anterior chest whose trigger points (TrPs) are among the most clinically important sources of chest, breast, and arm pain. Its referred pain patterns closely mimic cardiac ischemia and it has a direct somatovisceral relationship with cardiac arrhythmia. TrPs in this muscle are commonly overlooked as a myofascial source of chest pain that persists long after myocardial infarction.
'''Pectoralis Major''' is a large, multi-sectioned anterior chest muscle with one of the most clinically consequential trigger point (TrP) profiles in the body. Its referred pain patterns mimic ischaemic heart disease in exact detail, it produces breast pain and nipple hypersensitivity, and it has a direct somatovisceral relationship with cardiac arrhythmia. TrP shortening of this muscle drives the round-shouldered forward-head posture that perpetuates TrPs throughout the head, neck, and upper limb. Chest pain that persists long after myocardial infarction is often due to myofascial TrPs in the pectoral muscles that were activated viscerosomatic ally and never specifically inactivated.
 
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== Anatomy ==
== Anatomy ==


The pectoralis major consists of multiple overlapping laminae arranged in a playing-card (fan) configuration. It is divided into four sections by origin:
The pectoralis major consists of multiple overlapping laminae arranged like playing cards or roof shingles. It is divided into four sections by medial origin:


* '''Clavicular fibers''' — attach to the clavicle
* '''Clavicular section''' — fibres from the clavicle
* '''Sternal fibers''' — attach to the sternum
* '''Sternal section''' — fibres from the manubrium and sternum
* '''Costal fibers''' — attach to the cartilages of the second through sixth or seventh ribs
* '''Costal section''' — fibres from the cartilages of ribs 2–6 or 7
* '''Abdominal fibers''' — attach to the superficial aponeuroses of the obliquus externus abdominis and occasionally to the rectus abdominis
* '''Abdominal section''' — fibres from the superficial aponeurosis of the obliquus externus abdominis (occasionally to the rectus abdominis); most likely to be absent congenitally


All four sections attach '''laterally''' to the crest of the greater tubercle of the humerus (along the lateral lip of the groove for the bicipital tendon) in two layers — a ventral (superficial) layer and a dorsal (deep) layer. The lower sternocostal and abdominal fibers fold upward at the lateral end so that the lowermost fibers have the most proximal humeral attachment. This folding reverses the order of attachment and is essential to understanding the direction of palpable taut bands and the direction of local twitch responses on needle contact.
All four sections attach '''laterally''' to the crest of the greater tubercle of the humerus in two layers — a ventral (superficial) layer and a dorsal (deep) layer. The lower sternocostal and abdominal fibres fold upward at the lateral end so that the lowermost fibres have the most proximal humeral attachment. This folding reverses the order of attachment. Each lamina very likely has its own nerve branch and midfibre endplate zone — meaning TrPs can exist independently in different layers, with different fibre directions and different local twitch response directions.


The '''subclavius muscle''' lies beneath the clavicle over the first rib, attaching medially by a short thick tendon to the junction of the first rib with its cartilage and laterally in a groove on the under side of the middle third of the clavicle.
'''Innervation:'''
* Clavicular section: C5–C6 via the lateral pectoral nerve
* Sternal section: C6–C7
* Costal section: C7–C8 (transition zone between the two nerves)
* Costal and abdominal sections: C8–T1 via the medial pectoral nerve, which usually pierces the pectoralis minor en route


'''Innervation:''' The pectoralis major is innervated by the medial and lateral pectoral nerves. The clavicular section is supplied chiefly by spinal segments C5 and C6 (lateral pectoral nerve). The sternal section is innervated mainly by C6 and C7. The costal and abdominal sections are supplied by C8 and T1 through the medial pectoral nerve, which usually pierces the pectoralis minor muscle en route.
'''Primary actions:''' Adduction and medial rotation of the humerus (all fibres); glenohumeral flexion (clavicular section); extension/depression of the elevated arm (sternal, costal, and abdominal sections); protraction of the shoulder (all fibres).


'''Primary actions:''' When the thorax is fixed, the pectoralis major as a whole adducts and medially rotates the humerus. The upper fibers flex the humerus; the lower fibers depress the shoulder girdle. The clavicular section assists glenohumeral flexion and draws the arm across the chest. The sternal, costal, and abdominal fibers extend (lower) the arm from an elevated position but do not hyperextend. All fibers contribute to adduction, movement across the chest, and medial rotation.
The muscle influences three joints — sternoclavicular, acromioclavicular, and glenohumeral — and also the scapulothoracic gliding surface. Passive stretch must address all three articulations simultaneously; traction applied to the arm is an essential component.


'''Functional unit:''' All sections of the pectoralis major contract together during strong adduction, assisted by the teres major and minor, anterior and posterior deltoid, subscapularis, and long head of the triceps. For protraction of the shoulder, the serratus anterior, pectoralis minor, and subclavius assist. The clavicular section and the anterior deltoid work very closely together and are separated only by the groove of the cephalic vein. The major antagonists to the sternal section are the rhomboids and middle trapezius.
'''Functional unit:''' All sections contract together during strong adduction, assisted by teres major and minor, anterior and posterior deltoid, subscapularis, and long head of the triceps. For shoulder protraction, the serratus anterior, pectoralis minor, and subclavius assist. The clavicular section and anterior deltoid work very closely together, lying side-by-side and separated only by the groove of the cephalic vein. The major antagonists to the sternal section are the rhomboids and middle trapezius.


== Referred Pain Patterns ==
== Referred Pain Patterns ==


This muscle is likely to develop TrPs in five areas, each with a distinctive pain reference pattern. Pain and tenderness are referred unilaterally.
Pain and tenderness are referred unilaterally. This muscle is likely to develop TrPs in five distinct areas, each with a characteristic pattern.


'''Clavicular section''' TrPs refer pain over the anterior deltoid muscle and locally to the clavicular section itself.
{| class="wikitable"
! Section !! Essential pain zone !! Spillover / associated features
|-
| Clavicular || Anterior deltoid region; locally over the clavicular section || —
|-
| Intermediate sternal || Anterior chest (precordium if left-sided); medial arm accenting the medial epicondyle || Volar forearm; ulnar hand including last 2–2½ digits (exceeds standard ulnar nerve distribution); nocturnal pain; chest constriction mimicking angina
|-
| Medial sternal || Locally over the sternum; does not cross the midline || Parasternal pain
|-
| Costal / lateral border || Breast; nipple hypersensitivity; intolerance to clothing || Breast congestion / apparent oedema; affects both men and women
|-
| Cardiac arrhythmia TrP (right side only) || '''No spontaneous pain''' — tender on palpation only || Ectopic cardiac rhythm (supraventricular or ventricular premature contractions, paroxysmal tachycardia)
|}


'''Intermediate sternal section''' TrPs (three central TrP locations in the midfiber region) refer intense pain to the anterior chest — to the precordium if on the left side — and down the inner aspect of the arm. The arm pain accents the medial epicondyle. When sufficiently active, these TrPs also refer pain to the volar aspect of the forearm and ulnar side of the hand, including the last two or two-and-a-half digits (more than those innervated by the ulnar nerve alone). The uppermost of these sternal TrPs lies at the three-way overlap of the clavicular, manubrial, and sternal sections and the underlying pectoralis minor; TrPs occur frequently in both muscles at this location.
The uppermost sternal-section TrP lies at the three-way overlap of the clavicular, manubrial, and sternal sections, and the underlying pectoralis minor. TrPs occur frequently in both muscles at this location.


'''Medial sternal section''' TrPs refer pain locally and over the sternum without crossing the midline.
== Activation and Perpetuating Factors ==


'''Costal and abdominal section''' TrPs develop in two pectoral regions along the lateral free margin of the muscle. These border TrPs cause breast tenderness with hypersensitivity of the nipple, intolerance to clothing, and often breast pain.
; Postural (most important)
* '''Round-shouldered, forward-head posture''' — produces sustained shortening of the pectoral muscles; is the principal perpetuating factor and is bidirectional (TrP shortening induces round shoulders, which perpetuate the TrPs)
* Prolonged sitting while reading, writing, or using a computer without adequate lumbar and arm support
* Armrests that are too low, or chairs without armrests, causing the arms to be crossed in front of the chest
* Standing with a slouched, flat-chested posture


'''Cardiac arrhythmia TrP:''' 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 midway between the sternal margin and the nipple line. This TrP has been observed only on the right side, except in situs inversus. The spot tenderness of this TrP is associated with ectopic cardiac rhythms but not with any pain complaint. Inactivation of this TrP promptly restores normal sinus rhythm when it is contributing to ectopic supraventricular rhythm.
; Overload
* Heavy lifting, especially reaching forward
* Overuse of arm adduction (manual hedge clippers)
* Sustained lifting in a fixed position (power saw)
* Immobilisation of the arm in the adducted position (sling or cast)
* Sustained anxiety


'''Subclavius''' TrPs refer pain across the front of the shoulder and down the front of the arm along the radial side of the forearm, skipping the elbow and wrist to reappear on the radial half of the hand. The dorsal and volar aspects of the thumb, the index finger, and the middle finger may also hurt.
; Environmental
* Exposure of fatigued muscles to cold air (air conditioning, wet suit after swimming)


== Activation and Perpetuating Factors ==
; Viscerosomatic activation
* Acute myocardial infarction commonly refers pain to the midregion of the pectoralis major and minor, initiating TrPs via a viscerosomatic reflex; these TrPs tend to persist after recovery unless specifically inactivated


Pectoralis major TrPs are activated and perpetuated by a round-shouldered posture, as this produces sustained shortening of the pectoral muscles. Activation is likely to occur during prolonged sitting, reading, and writing, and when standing with a slouched, flat-chested posture. Conversely, TrP shortening in this muscle can induce such posture.
== Symptoms ==


TrPs may be initiated or reactivated by: heavy lifting (especially reaching out in front), overuse of arm adduction (manual hedge clippers), sustained lifting in a fixed position (power saw), immobilisation of the arm in the adducted position (arm in a sling or cast), sustained high levels of anxiety, or exposure of fatigued muscles to cold air.
{| class="wikitable"
 
! Section active !! Dominant complaint !! Clinical trap
In acute myocardial infarction, pain is commonly referred from the heart to the midregion of the pectoralis major and minor muscles. The injury to heart muscle initiates a viscerosomatic process that activates TrPs in the pectoral muscles. Following recovery from the acute infarction, these self-perpetuating TrPs tend to persist in the chest wall unless specifically inactivated.
|-
| Clavicular || Anterior shoulder pain; restricted horizontal abduction || Bicipital tendinitis; subacromial bursitis; C5–C6 radiculopathy
|-
| Intermediate sternal (left) || Intense precordial chest pain radiating to medial arm, forearm, and ulnar hand; chest constriction; nocturnal pain || '''Angina pectoris; myocardial ischaemia''' — the most dangerous misdiagnosis in myofascial medicine
|-
| Intermediate sternal (right) || Anterior chest and arm pain || Costochondritis; Tietze's syndrome; C7–C8 radiculopathy
|-
| Medial sternal || Circumscribed unilateral parasternal pain not crossing midline || Costochondritis; enthesopathy at sternocostal junction; fibromyalgia tender point at 2nd rib
|-
| Lateral costal border || Breast tenderness; nipple hypersensitivity; intolerance to clothing; breast congestion || Breast cancer (unexpressed fear); fibrocystic disease — patients express enormous relief when the myofascial origin is identified
|-
| Arrhythmia TrP (right only) || No spontaneous pain; incidental finding during arrhythmia workup || Idiopathic ectopic rhythm attributed to structural cardiac pathology
|}


Shortening of the subclavius muscle due to TrPs can contribute to symptoms of a vascular thoracic outlet syndrome by drawing the clavicle down toward the subclavian artery and vein as they pass over the first rib.
Additionally: patients with pectoral TrPs are often more aware of their secondary '''interscapular back pain''' (overloaded middle trapezius and rhomboid antagonists) than of the anterior chest pain itself. The pectoral TrPs may be latent but still cause this referred overload pattern. Patients with the diagnosis of angina pectoris are naturally fearful of any activity that produces the pain — this fear inhibits full movement, accelerates physical and psychological deterioration, and perpetuates the TrPs.


== Clinical Examination ==
== Clinical Examination ==


The patient should be observed initially for a stooped, round-shouldered, head-forward posture and weak interscapular muscles. Observing from the rear, the examiner may see abducted scapulae.
=== Postural Assessment ===
Observe the patient initially for:
* Stooped, round-shouldered, head-forward posture
* Abducted scapulae (viewed from behind)
* Weak interscapular muscles


TrPs in the pectoralis major cause minimal restriction of motion at the shoulder when it is involved alone, as shown by the Hand-to-Shoulder-Blade Test. The myofascial TrPs of the pectoral muscles do restrict scapular adduction, which can be tested by having the patient place the back of the ipsilateral hand on the hip and move the elbow posteriorly for range of backward movement. Bilateral comparison is the most sensitive indicator of restriction if muscle involvement is unilateral. Production of interscapular pain is another indicator of restriction.
When the cheekbone is in the same vertical plane as the sternal notch, the head and neck are in erect position without muscular overload. See [[Concept:Postural_Considerations]] for the full postural assessment and correction protocol.


Weakness of the clavicular and sternal portions for adduction at the glenohumeral joint is tested with the patient supine, the arm held straight up in the air, and the opposite shoulder stabilised against the table. The costal and abdominal sections can be similarly tested by resisting the patient's attempt to adduct the elevated arm obliquely downward toward the contralateral iliac crest.
=== Range of Motion and Strength ===
TrPs in the pectoralis major cause '''minimal restriction of glenohumeral motion''' when the muscle is involved alone — the Hand-to-Shoulder-Blade Test is not a sensitive indicator for this muscle.


When a patient complains of breast soreness (referred tenderness), a feeling of congestion in that breast may also be described. The breast may be slightly enlarged and feel doughy — signs of impaired lymph drainage, possibly due to entrapment or reflex inhibition of peristalsis of the lymphatic vessels, which disappear after inactivation of the responsible TrPs in the lateral border of the pectoralis major.
The more useful tests are:


The diagnosis of angina pectoris is sometimes made clinically when there is no definite evidence that the chest pain is due to myocardial ischaemia. In many such patients, one can demonstrate that the pain is referred from TrPs in the pectoralis major muscle.
* '''Scapular adduction test:''' Have the patient place the back of the ipsilateral hand on the hip and move the elbow posteriorly. Restriction compared to the contralateral side indicates pectoral TrP involvement; production of interscapular pain is another indicator. Bilateral comparison is the most sensitive indicator when involvement is unilateral (which it seldom is in the pectorals).
* '''Stretch range fan-wise (supine):''' Move the arm into horizontal abduction, lateral rotation, and elevation in the different fibre directions. A sensitive operator can feel the restriction of the involved taut band; the patient feels increased tension, often as local pain, in the involved section.
* '''Strength testing (supine):'''
** Clavicular and sternal sections: resist adduction at the glenohumeral joint with the arm held straight up
** Costal and abdominal sections: resist adduction of the elevated arm obliquely downward toward the contralateral iliac crest


=== Cardiac Origin: Distinguishing Features ===
=== Cardiac Arrhythmia TrP Examination ===
This TrP produces '''no spontaneous pain''' and is found only by deliberate palpation in a patient with unexplained ectopic rhythm.


A definite diagnosis of active myofascial TrPs based on their characteristic signs and symptoms and a dramatic response to local treatment does NOT exclude cardiac disease. A disorder of the heart may coexist and must be ruled out by appropriate tests of cardiac function.
Locate the tip of the xiphoid process. At that level on the '''right side only''', in a vertical line midway between the sternal border and the nipple line, press upward against the inferior edge of the fifth rib and explore the hollow between the fifth and sixth ribs for spot tenderness.


Myofascial TrP pain shows a much wider variability in its response to activity from day to day than does the more consistent exercise response of angina pectoris. Relief of pain by a vapocoolant spray or by local injection cannot be used diagnostically to exclude myocardial ischaemia as a cause of the pain. The cardiac status should be known in every patient who experiences relief of chest pain by these simple measures.
=== Breast Examination ===
When breast pain or nipple hypersensitivity is present, palpate the lateral free margin (anterior axillary fold) for TrPs in the costal section. Signs of lymphatic drainage impairment (slight breast enlargement, doughy texture) support the diagnosis — these resolve after TrP inactivation.


Complaints of circumscribed areas of unilateral parasternal pain should arouse suspicion of parasternal TrPs in the pectoralis major muscle.
== Differential Diagnosis ==


=== Somatovisceral and Viscerosomatic Effects ===
=== Cardiac ===


A common example of a somatovisceral response is found in the patient who experiences episodes of supraventricular tachycardia, supraventricular premature contractions, or ventricular premature contractions without other evidence of heart disease. The patient with such an ectopic rhythm should be checked for an active TrP in the right pectoral region between the fifth and sixth ribs at the specific cardiac arrhythmia site.
{| class="wikitable"
! Feature !! Myofascial TrP (pectoralis major) !! Angina pectoris / ACS
|-
| Pain character || Aching, muscular; reproduced precisely by TrP palpation || Pressure, tightness, constriction; not reproducible by chest wall palpation
|-
| Activity relationship || Variable day-to-day; inconsistent relationship to exertion || Consistent threshold with exertion; predictable exercise response
|-
| Chest wall palpation || Taut band, spot tenderness, local twitch response; familiar pain reproduced || No taut band; diffuse or absent chest wall tenderness
|-
| Response to vapocoolant / local injection || Relieves the TrP pain; does NOT modify ECG ischaemic response if true CAD coexists || Vapocoolant to the referred pain area may relieve anginal pain without altering the ECG — so relief alone cannot exclude ischaemia
|-
| ECG / troponin || Normal; noncardiac pain may induce transient T-wave changes || Abnormal with active ischaemia
|-
| Response to nitrates || Occasionally relieves (nitrates dilate peripheral vessels) || Reliably relieves (though placebo sometimes equally effective)
|}


A myofascial viscerosomatic interaction begins with coronary artery insufficiency or other intrathoracic disease that refers pain from these visceral structures to the anterior chest wall. As a result, satellite TrPs develop in the somatic pectoral muscles. Among 72 patients with cardiac disease, 61% had tender TrPs in the chest muscles.
'''Critical rule:''' A diagnosis of active myofascial TrPs with a dramatic response to local treatment does '''NOT''' exclude cardiac disease. The cardiac status must be established in every patient who experiences relief of chest pain by these measures. The conditions coexist.


== Trigger Point Examination ==
=== Non-cardiac Chest Pain ===
 
Most TrPs found in the clavicular section and all TrPs in the parasternal section are identified by flat palpation. TrPs in the intermediate and lateral parts of the sternal and costal sections are best located by pincer palpation with the muscle placed on moderate tension by abducting the arm to approximately 90°. Pressure on the tender spot should produce sensations recognised by the patient as recently experienced symptoms. Local twitch responses may be elicited.
 
To find the cardiac arrhythmia TrP, the tip of the xiphoid process is first located. Then, at this level on the right side, in a vertical line midway between the sternal border and the nipple line, the region of the hollow between the fifth and sixth ribs is examined for a tender spot. This TrP is found by pressing upward against the inferior edge of the fifth rib and exploring for spot tenderness.
 
For the subclavius muscle, since it must be palpated through the clavicular division of the pectoralis major, the relaxed patient's arm is placed in adduction and medial rotation. The examiner can palpate subclavius central TrPs at the lateral portion of the medial third of the clavicle by rolling the thumb underneath the clavicle, deep into the recess and across the tense fibres. One should distinguish the attachment TrP (ATrP) tenderness just lateral to and below the costoclavicular joint from the central TrP tenderness found closer to midclavicle.
 
== Entrapment ==
 
No direct nerve entrapments by the pectoralis major have been confirmed. However, shortening of the subclavius muscle due to TrPs will draw the clavicle down toward the subclavian artery and vein as they pass over the first rib, which can at least contribute to, if not cause, entrapment and the symptoms of a vascular thoracic outlet syndrome.
 
Lymphatic drainage from the breast usually travels in front of and around the pectoralis major muscle to the axillary lymph nodes. Entrapment of this lymph duct by passage between tense fibres of an involved pectoralis major muscle may cause oedema of the breast. In these patients with TrPs, the signs of entrapped lymphatic drainage and breast tenderness are relieved by inactivation of the related pectoralis major TrPs.
 
== Differential Diagnosis ==


{| class="wikitable"
{| class="wikitable"
! Condition !! Key distinguishing features
|-
|-
! Condition !! Distinguishing features
| [[Muscle:Pectoralis_Minor|Pectoralis minor TrPs]] || Similar pain pattern; anatomically adjacent; almost always coexists — the uppermost sternal TrP lies at the three-way overlap of both muscles
|-
|-
| Angina pectoris / cardiac ischaemia || Must always be excluded; myofascial TrP pain shows wider day-to-day variability in response to activity than consistent exercise-triggered angina; relief by vapocoolant or local injection does NOT rule out cardiac origin; cardiac status must be established
| Costochondritis / Tietze's syndrome || Localised swelling and tenderness at costochondral junction; no taut band; may coexist
|-
|-
| Myocardial infarction — persistent chest pain || Chest pain persisting long after MI is often due to myofascial TrPs activated viscerosomatic ally; these TrPs persist in the chest wall until specifically inactivated
| Chest wall syndrome / precordial catch / slipping rib / rib-tip syndrome || Each has specific localising signs; all can be relieved by local injection — consistent with possible TrP origin; examine specifically for TrPs in each case
|-
|-
| Pectoralis minor TrPs || Similar referred pain pattern and close anatomical relationship; the same muscles commonly associated with pectoralis major involvement are likely to also harbour pectoralis minor TrPs; the two are frequently active simultaneously
| C5–C8 radiculopathy || Dermatomal sensory changes; reflex changes; neurological examination abnormal
|-
|-
| Scalene TrPs || Also refer pain to the pectoral region; considered when chest and arm pain pattern matches but pectoral TrPs are absent or insufficient to explain the full pattern
| Intercostal neuritis / radiculopathy || Dermatomal distribution; sharp/burning quality; aggravated by respiration
|-
|-
| Bicipital tendinitis, supraspinatus tendinitis, subacromial bursitis, medial epicondylitis, lateral epicondylitis || These and C5–C6, C7, C8 radiculopathy, intercostal neuritis, irritation of bronchi/pleura/oesophagus, hiatal hernia with reflux, distension of stomach by gas, mediastinal emphysema, gaseous distension of splenic flexure of colon, and lung cancer are differential diagnoses to consider for chest pain and tenderness
| Hiatal hernia / oesophageal reflux / splenic flexure gas / lung cancer || GI or respiratory symptoms; no taut band; investigations required
|-
|-
| Chest wall syndrome / Tietze's syndrome / costochondritis / hypersensitive xiphoid syndrome / slipping rib syndrome / rib-tip syndrome || Each patient should be carefully examined to determine if symptoms are partially or entirely due to myofascial referred pain and tenderness, especially from pectoralis major TrPs; each of these conditions has been reported as sometimes relieved by injection of the tender area with a local anaesthetic
| Fibromyalgia tender point at 2nd rib || Tender points at sternocostal junction of 2nd rib may be confused with costochondritis or pectoralis major attachment TrPs — distinguish by identifying the taut band
|-
|-
| Fibromyalgia || Tender points consistent with fibromyalgia syndrome occur directly over the sternocostal junction of the second rib
| [[Differential:ThoracicOutletSyndrome|Pseudo-thoracic outlet syndrome]] || Pectoralis major is one of the four muscles comprising the myofascial pseudo-TOS quadrad (with latissimus dorsi, teres major, and subscapularis); individually and in combination these muscles produce referred pain confusingly mimicking TOS; a true compressive TOS (from scalene TrPs) may coexist
|}
|}
=== Related Trigger Points ===
* [[Muscle:Pectoralis_Minor|Pectoralis minor]] — co-active; similar pain pattern; medial pectoral nerve pierces it
* [[Muscle:Subclavius|Subclavius]] — almost invariably involved alongside clavicular section TrPs; examine specifically (see separate page)
* Anterior deltoid — satellite TrP; lies within the pectoralis major pain reference zone; likely to develop first
* [[Muscle:Subscapularis|Subscapularis]] and [[Muscle:Latissimus_Dorsi|latissimus dorsi]] — synergistic unit; develop active TrPs in sequence
* [[Muscle:Serratus_Anterior|Serratus anterior]], rhomboids, and middle [[Muscle:Trapezius/Middle|trapezius]] — antagonists that develop painful stretch weakness from tense pectorals; rhomboids and middle trapezius can also develop latent TrPs activated by unaccustomed shortening during pectoral stretch — release with non-stretch procedures before strengthening
* Infraspinatus, teres minor, posterior deltoid — with progressive restriction, these develop active TrPs leading to a frozen shoulder
* [[Muscle:Sternocleidomastoid|SCM (clavicular head)]] — clavicular pectoral TrP shortening pulls the medial clavicle forward and downward, tensioning the clavicular head of the SCM and activating TrPs there with autonomic consequences
== Trigger Point Examination ==
Palpate with the arm abducted to approximately 90° to place the muscle on moderate tension and maximise spot tenderness.
* '''Clavicular section''' and '''parasternal fibres:''' flat palpation
* '''Intermediate and lateral sternal and costal sections:''' pincer palpation — encircle the muscle fold between thumb and fingers; the lateral border of the pectoralis major is one of the easier muscles in which to identify nodules and taut bands. Local twitch responses are often highly visible.
* '''Upper and midsternal sections''' (in patients with mobile subcutaneous tissue): pincer palpation by inserting the fingers between the underside of the muscle and the chest wall
The most reliable diagnostic criteria are: palpable taut band, spot tenderness within it, reproduction of the patient's familiar pain, and a local twitch response.
== Entrapment ==
No direct nerve entrapments by the pectoralis major have been confirmed.
Lymphatic drainage from the breast may be entrapped by tense pectoral fibres (a lymph vessel from the cephalad breast may pierce the pectoralis major to reach subclavicular nodes), causing breast oedema that resolves with TrP inactivation.


== Treatment ==
== Treatment ==


=== Trigger Point Release ===
=== Postural Correction ===
Correction of round-shouldered posture is '''essential for lasting relief''' and must accompany all other treatment. See [[Concept:Postural_Considerations]] for the full protocol covering standing, sitting, lumbar support, and dynamic movement correction.


Correction of round-shouldered posture and maintenance of good dynamic posture are essential for lasting relief. In addition to spray-and-stretch, other techniques including trigger point pressure release, postisometric relaxation, and contract-relax are effective for release of '''central''' TrPs in the pectoralis major. The primary therapeutic approach to '''attachment''' TrPs is to inactivate the central TrPs causing them.
=== Spray and Stretch ===
See [[Concept:Apropos_Treatment|Apropos Treatment]] for general principles.


For spray and stretch, all sections of the pectoralis major are usually more effectively stretched with the patient seated than supine, as the seated position permits greater motion of both the scapula and arm. The muscle must be effectively stretched across three articulations (sternoclavicular, acromioclavicular, and glenohumeral). Traction is applied to the arm as part of the stretch.
All sections are more effectively stretched with the patient '''seated''' than supine — seated position allows greater scapular and arm motion. Traction must be applied to the arm as part of the stretch. The subscapularis must also be released if its TrPs are limiting pectoral stretch; include its spray pattern alternately.


For the '''clavicular section''', the arm is laterally rotated and horizontally extended (abducted) slightly below 90° at the shoulder to fully take up the slack in the clavicular fibres. Vapocoolant spray is swept laterally from the clavicle across the muscle and then over the shoulder and upper limb to cover the referred pain pattern.
Check and treat the contralateral pectoralis major — both are frequently involved in round-shouldered posture.


For the '''intermediate sternal fibres''', the arm is placed at approximately 90° of abduction, then laterally rotated and moved slowly toward the back into extension. Parallel sweeps of vapocoolant are directed laterally and upward across the sternal portion of the muscle, starting at the sternum and continuing over the upper limb to cover all referred pain patterns.
* '''Clavicular section:''' Arm laterally rotated and horizontally extended (abducted) slightly below 90°; spray swept laterally from the clavicle across the muscle, over the shoulder and upper limb
* '''Intermediate sternal section:''' Arm at 90° abduction, laterally rotated, then moved slowly into extension; spray swept laterally and upward across the sternal portion, continuing over the upper limb including the fingers
* '''Parasternal TrPs:''' Same stretch position; spray swept medially over the TrPs and pain reference zone to the midline
* '''Lowest costal section:''' Arm flexed at shoulder in lateral rotation; spray directed downward and medially from the humerus, also covering the breast


For the '''lowest costal section''', the arm is flexed at the shoulder while held in lateral rotation. When there is no more slack, sweeps of spray or icing are directed downward and medially from the humerus over the passively stretched fibres, also covering the tender breast.
Follow with three slow cycles of full active range of motion and moist heat.


Latent TrPs of the antagonistic rhomboid and middle trapezius muscles can be activated by unaccustomed shortening during stretch of the pectoralis major. These interscapular muscles should be released by vapocooling and non-stretch procedures followed by strengthening exercises.
'''Important caution:''' Vapocooling the skin over the pectoralis major may relieve the pain of true cardiac ischaemia as well as myofascial pain. The cardiac status must be known in every patient who experiences relief of chest pain by these measures.


Residual TrPs (including those in the subclavius) can usually be inactivated by trigger point pressure release or by injection with 0.5% procaine solution, followed by brief stretch and spray and then moist heat. Three slow cycles of full active range of motion follow immediately after TrP injection; this activity "re-educates" the muscle in its normal range of motion.
=== Other Manual Techniques ===
Postisometric Relaxation (PIR), trigger point pressure release, and contract-relax techniques are effective for central TrPs. The primary approach to attachment TrPs (parasternal enthesopathy along the sternal border) is to inactivate the corresponding central TrPs.


=== Arrhythmia Trigger Points ===
=== Trigger Point Injection ===
See [[Concept:Trigger_Point_Injection|Trigger Point Injection]] for general principles.


Before attempting to inactivate the arrhythmia TrP itself, it is best to inactivate all of the sternal division TrPs first. The arrhythmia TrP and the parasternal TrPs require repeated application of trigger point pressure release, stripping massage, and, as a last resort, local anaesthetic injection. The patient with arrhythmias should be taught the self-application of trigger point pressure release using the thumb of one hand on top of the finger of the other hand to reinforce it, increasing pressure directed onto the tender TrP against the rib for a minute or more. Some patients can learn to abort a paroxysmal ectopic tachycardia as soon as the attack is recognised.
The patient lies supine for all injections.


=== Trigger Point Injection ===
'''Critical safety principle:''' Needles directed over the thoracic cage must be aimed nearly tangent to the chest wall to avoid pneumothorax. This applies to the clavicular and mid/lower-sternal sections.


The patient lies supine for all injections of TrPs in the pectoralis major.
; Clavicular section
Flat palpation; needle aimed cephalad and nearly tangent to the chest wall.


'''Clavicular section:''' Using flat palpation, the clinician localises these TrPs between the fingers for injection. The needle is aimed cephalad and nearly tangent with the chest wall.
; Upper sternal section
Flat palpation; injected in the region of the uppermost TrP. Pincer palpation may be used in patients with mobile subcutaneous tissue by inserting the fingers between the underside of the muscle and the chest wall.


'''Upper sternal section:''' TrPs are usually located by flat palpation and injected in the region of the uppermost X. In patients with highly mobile subcutaneous tissue, active TrPs in the upper and midsternal sections may be reached using pincer palpation by inserting the fingers between the underside of the pectoralis major and the chest wall.
; Mid- and lower-sternal sections
Flat palpation; 37 mm (1.5 inch) needle directed upward toward the coracoid process, nearly parallel to the thoracic cage.


'''Mid- and lower-sternal sections:''' TrPs are injected with a 37mm (1.5 in) needle directed upward toward the coracoid process, nearly parallel to the thoracic cage. The needle is not directed nearly tangent to the chest wall — beware of entering the pleura.
; Parasternal attachment TrPs
Flat palpation; inject as for mid-sternal. Sustained relief requires inactivation of the corresponding central TrPs first.


'''Costal section:''' The muscle is grasped between the thumb and fingers of one hand so that the TrPs can be precisely injected by palpating and localising the TrP between the fingers. The needle may be directed perpendicularly to the skin so it can reach a cluster of TrPs in the middle or on the far side of the fold.
; Costal / lateral border section
Pincer palpation of the anterior axillary fold; needle directed perpendicularly for deep TrPs, at acute angle to fibres for superficial ones. Multiple TrPs may be reached through one skin penetration. Haemostasis by constant counterpressure during and after each injection.


'''Cardiac arrhythmia TrP:''' After locating the precise spot tenderness by flat palpation, the needle is directed cephalad toward the fifth rib. The needle is aimed nearly tangential to the skin, since the TrP lies no deeper than the anterior surface of the lower border of the rib.
; Arrhythmia TrP (right side only)
Locate the precise spot tenderness by flat palpation between the fifth and sixth ribs on the right. Needle directed cephalad toward the fifth rib, aimed nearly tangential to the skin. This TrP lies no deeper than the anterior surface of the lower border of the fifth rib. '''Inactivate all sternal division TrPs before attempting the arrhythmia TrP.''' Teach the patient self-application of trigger point pressure release to abort paroxysmal ectopic tachycardia.


For all parts of the pectoralis major, TrP injection is followed by 3 slow cycles of full active range of motion.
Post-injection: three slow cycles of full active range of motion; moist heat. Residual TrPs may be inactivated by trigger point pressure release and/or stretch and spray.


=== Corrective Actions ===
== Corrective Actions ==


Patients who have no demonstrable evidence of heart disease but who suffer from chest pain that they understood to be of cardiac origin need patient education: by demonstrating to these patients that the kind and distribution of their pain is reproduced by pressure on the TrPs and by demonstrating local twitch responses, the patients are convinced that the pain is indeed myofascial and not life-threatening cardiac in origin.
=== Patient Education — Cardiac Mimicry ===
For patients with no demonstrable cardiac disease who have been living with fear of a cardiac diagnosis: demonstrating that their familiar pain is reproduced precisely by TrP palpation, and showing local twitch responses, convinces patients that the pain is myofascial rather than life-threatening. This is clinically essential — the fear itself inhibits movement and perpetuates the TrPs. When coronary artery disease and pectoralis major TrPs coexist, relief of the TrP-induced pain is important for more than comfort, as pain itself may reflexly diminish coronary artery calibre.


Good static and dynamic posture must be learned and maintained. The In-doorway Stretch Exercise is useful to stretch all the adductors and medial rotators at the shoulders. The patient stands in a narrow doorway with the forearms flat against the door facings to anchor the forearms, and steps forward through the doorway to stretch the muscles. The patient does NOT grasp the doorjamb. The hand position against the doorjamb is adjusted to apply the stretch to different taut bands: fibres of the clavicular section are stretched best in the lower hand-position; by raising the hands to the middle hand-position with the upper arms horizontal, the sternal section is stretched; moving the hands as high as possible while keeping the forearms against the doorjambs stretches the costal and more vertical abdominal fibres that form the lateral margin of the muscle.
=== Postural Reconditioning ===
See [[Concept:Postural_Considerations]] for the full standing, sitting, and movement protocol. Key practical points:
* Shift body weight from heels onto the balls of the feet to restore cervical and lumbar curves effortlessly
* Move the ischial tuberosities toward the front edge of the chair; one foot placed posteriorly
* Lumbar roll at belt height for all prolonged sitting, including driving
* Chair armrests at the height of the half-flexed elbow — absence of armrests causes the arms to cross in front of the chest, shortening the pectorals


When sleeping, the patient must avoid shortening the pectoralis major — the arms should not be folded across the chest. The corner of the pillow should be tucked between the head and shoulder to drop the shoulder backward. When lying on the pain-free side, the uppermost forearm should be supported on a pillow to prevent the arm from dropping forward and thus shortening the affected pectoralis major. When lying on the affected side, the pillow fits in the axilla between the arm and chest to maintain some degree of pectoralis major stretch.
=== Sleeping Posture ===
* Avoid sleeping with arms folded across the chest
* When lying on the pain-free side: support the uppermost forearm on a pillow to prevent the arm from dropping forward and shortening the affected pectoralis major
* When lying on the affected side: tuck the pillow in the axilla between the arm and chest to maintain pectoral stretch
* Corner of the pillow tucked between head and shoulder to drop the shoulder backward


Patients with large heavy breasts commonly have bras that exert constricting pressure around the chest that makes deep indentations in the skin, which can aggravate and perpetuate pectoralis major TrPs. The tension around the chest must be eased either by adding a bra extender between the hooks or by releasing some of the elasticity built into the bra by using a hot iron.
=== In-doorway Stretch Exercise ===
Stand in a narrow doorway with the forearms flat against the door facings (do not grasp the doorjamb — this interferes with muscle relaxation). One foot forward with the forward knee bent. Shift the body through the doorway for a slow, gentle, passive bilateral stretch. Stretch only to the point of comfortable tension without pain. Hold briefly, relax, breathe slowly between cycles.


== Satellite Trigger Points ==
Hand position determines which section is stretched:
* Lower hand position → clavicular section
* Middle hand position (upper arms horizontal) → sternal section
* Hands as high as possible → costal and abdominal sections


* [[Muscle:Pectoralis Minor|Pectoralis minor]] — one rarely finds active TrPs in the pectoralis minor without active TrPs in the pectoralis major; the same muscles commonly associated with pectoralis major involvement also harbour pectoralis minor TrPs
=== Bra Modification ===
* Anterior deltoid — especially likely to develop satellite TrPs as it lies within the pain reference zone of the pectoralis major; closely associated functionally
Tight circumferential bra pressure aggravates and perpetuates costal section TrPs. Add a bra extender between the hooks, or reduce built-in elasticity by using a hot iron.
* [[Muscle:Scalene|Scalene muscles]] — active TrPs in the scalenes refer pain to the pectoral region; pectoralis major TrPs may develop as satellites
* Subscapularis and latissimus dorsi — also part of the synergistic functional unit; may develop active TrPs before long
* Rhomboids and middle trapezius (antagonists) — can develop latent TrPs activated by unaccustomed shortening during stretch of the pectoralis major


== Related Pages ==
== Related Pages ==


* [[Pain:Ear and TMJ]] — pain algorithm for head and neck
* [[Pain:Front-of-Chest|Pain: Front-of-Chest]] — Diagnostic algorithm
* [[Muscle:Pectoralis Minor]] — intimately co-active muscle
* [[Pain:Side-of-Chest|Pain: Side-of-Chest]] — Costal and abdominal sections contribute
* [[Muscle:Scalene]] — satellite and functional unit overlap
* [[Muscle:Subclavius|Subclavius]] — Almost always co-active with clavicular section TrPs; examine separately
* [[Muscle:Sternalis]] — overlying anomalous muscle; satellite TrPs from lower sternal SCM division refer downward over sternum
* [[Muscle:Pectoralis_Minor|Pectoralis Minor (Chapter 43)]] — Co-active; similar pain pattern
* [[Muscle:Sternalis|Sternalis (Chapter 44)]] — Overlies pectoralis major; parasternal TrPs may be in either
* [[Muscle:Serratus_Anterior|Serratus Anterior (Chapter 46)]] — Antagonist; develops stretch weakness
* [[Muscle:Subscapularis|Subscapularis]] — Synergist; limits pectoral stretch if involved
* [[Muscle:Latissimus_Dorsi|Latissimus Dorsi]] — Part of the pseudo-TOS quadrad
* [[Muscle:Sternocleidomastoid|Sternocleidomastoid]] — Activated by clavicular section shortening
* [[Differential:ThoracicOutletSyndrome|Thoracic Outlet Syndrome]] — Myofascial pseudo-TOS vs true TOS
* [[Concept:Postural_Considerations|Postural Considerations]] — Essential for lasting relief
* [[Concept:Trigger_Point_Injection|Trigger Point Injection]]
* [[Concept:Apropos_Treatment|Apropos Treatment]]
* [[Concept:_Apropos_Assessment|Apropos Assessment]]


== References ==
== References ==


* Travell JG, Simons DG. ''Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body''. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 42.
* Travell JG, Simons DG. ''Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body''. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 42 (pp. 819–843).
* Travell JG, Simons DG. ''Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1''. 2nd ed. Chapter 41 (pp. 801–818).


[[Category:Muscle]]
[[Category:Muscle]]
[[Category:Vol1 Ch42]]
[[Category:Vol1_Ch42]]
[[Category:Torso Pain]]
[[Category:Torso]]

Latest revision as of 08:46, 28 May 2026

Pectoralis Major is a large, multi-sectioned anterior chest muscle with one of the most clinically consequential trigger point (TrP) profiles in the body. Its referred pain patterns mimic ischaemic heart disease in exact detail, it produces breast pain and nipple hypersensitivity, and it has a direct somatovisceral relationship with cardiac arrhythmia. TrP shortening of this muscle drives the round-shouldered forward-head posture that perpetuates TrPs throughout the head, neck, and upper limb. Chest pain that persists long after myocardial infarction is often due to myofascial TrPs in the pectoral muscles that were activated viscerosomatic ally and never specifically inactivated.

⚠ Safety Notice: Procedures described on this page involve structures in close proximity to major vessels or neurovascular bundles. This page is intended for qualified clinicians. Always identify relevant anatomy before proceeding. This site is not validated for clinical use — see the site disclaimer.

Anatomy

The pectoralis major consists of multiple overlapping laminae arranged like playing cards or roof shingles. It is divided into four sections by medial origin:

  • Clavicular section — fibres from the clavicle
  • Sternal section — fibres from the manubrium and sternum
  • Costal section — fibres from the cartilages of ribs 2–6 or 7
  • Abdominal section — fibres from the superficial aponeurosis of the obliquus externus abdominis (occasionally to the rectus abdominis); most likely to be absent congenitally

All four sections attach laterally to the crest of the greater tubercle of the humerus in two layers — a ventral (superficial) layer and a dorsal (deep) layer. The lower sternocostal and abdominal fibres fold upward at the lateral end so that the lowermost fibres have the most proximal humeral attachment. This folding reverses the order of attachment. Each lamina very likely has its own nerve branch and midfibre endplate zone — meaning TrPs can exist independently in different layers, with different fibre directions and different local twitch response directions.

Innervation:

  • Clavicular section: C5–C6 via the lateral pectoral nerve
  • Sternal section: C6–C7
  • Costal section: C7–C8 (transition zone between the two nerves)
  • Costal and abdominal sections: C8–T1 via the medial pectoral nerve, which usually pierces the pectoralis minor en route

Primary actions: Adduction and medial rotation of the humerus (all fibres); glenohumeral flexion (clavicular section); extension/depression of the elevated arm (sternal, costal, and abdominal sections); protraction of the shoulder (all fibres).

The muscle influences three joints — sternoclavicular, acromioclavicular, and glenohumeral — and also the scapulothoracic gliding surface. Passive stretch must address all three articulations simultaneously; traction applied to the arm is an essential component.

Functional unit: All sections contract together during strong adduction, assisted by teres major and minor, anterior and posterior deltoid, subscapularis, and long head of the triceps. For shoulder protraction, the serratus anterior, pectoralis minor, and subclavius assist. The clavicular section and anterior deltoid work very closely together, lying side-by-side and separated only by the groove of the cephalic vein. The major antagonists to the sternal section are the rhomboids and middle trapezius.

Referred Pain Patterns

Pain and tenderness are referred unilaterally. This muscle is likely to develop TrPs in five distinct areas, each with a characteristic pattern.

Section Essential pain zone Spillover / associated features
Clavicular Anterior deltoid region; locally over the clavicular section —
Intermediate sternal Anterior chest (precordium if left-sided); medial arm accenting the medial epicondyle Volar forearm; ulnar hand including last 2–2½ digits (exceeds standard ulnar nerve distribution); nocturnal pain; chest constriction mimicking angina
Medial sternal Locally over the sternum; does not cross the midline Parasternal pain
Costal / lateral border Breast; nipple hypersensitivity; intolerance to clothing Breast congestion / apparent oedema; affects both men and women
Cardiac arrhythmia TrP (right side only) No spontaneous pain — tender on palpation only Ectopic cardiac rhythm (supraventricular or ventricular premature contractions, paroxysmal tachycardia)

The uppermost sternal-section TrP lies at the three-way overlap of the clavicular, manubrial, and sternal sections, and the underlying pectoralis minor. TrPs occur frequently in both muscles at this location.

Activation and Perpetuating Factors

Postural (most important)
  • Round-shouldered, forward-head posture — produces sustained shortening of the pectoral muscles; is the principal perpetuating factor and is bidirectional (TrP shortening induces round shoulders, which perpetuate the TrPs)
  • Prolonged sitting while reading, writing, or using a computer without adequate lumbar and arm support
  • Armrests that are too low, or chairs without armrests, causing the arms to be crossed in front of the chest
  • Standing with a slouched, flat-chested posture
Overload
  • Heavy lifting, especially reaching forward
  • Overuse of arm adduction (manual hedge clippers)
  • Sustained lifting in a fixed position (power saw)
  • Immobilisation of the arm in the adducted position (sling or cast)
  • Sustained anxiety
Environmental
  • Exposure of fatigued muscles to cold air (air conditioning, wet suit after swimming)
Viscerosomatic activation
  • Acute myocardial infarction commonly refers pain to the midregion of the pectoralis major and minor, initiating TrPs via a viscerosomatic reflex; these TrPs tend to persist after recovery unless specifically inactivated

Symptoms

Section active Dominant complaint Clinical trap
Clavicular Anterior shoulder pain; restricted horizontal abduction Bicipital tendinitis; subacromial bursitis; C5–C6 radiculopathy
Intermediate sternal (left) Intense precordial chest pain radiating to medial arm, forearm, and ulnar hand; chest constriction; nocturnal pain Angina pectoris; myocardial ischaemia — the most dangerous misdiagnosis in myofascial medicine
Intermediate sternal (right) Anterior chest and arm pain Costochondritis; Tietze's syndrome; C7–C8 radiculopathy
Medial sternal Circumscribed unilateral parasternal pain not crossing midline Costochondritis; enthesopathy at sternocostal junction; fibromyalgia tender point at 2nd rib
Lateral costal border Breast tenderness; nipple hypersensitivity; intolerance to clothing; breast congestion Breast cancer (unexpressed fear); fibrocystic disease — patients express enormous relief when the myofascial origin is identified
Arrhythmia TrP (right only) No spontaneous pain; incidental finding during arrhythmia workup Idiopathic ectopic rhythm attributed to structural cardiac pathology

Additionally: patients with pectoral TrPs are often more aware of their secondary interscapular back pain (overloaded middle trapezius and rhomboid antagonists) than of the anterior chest pain itself. The pectoral TrPs may be latent but still cause this referred overload pattern. Patients with the diagnosis of angina pectoris are naturally fearful of any activity that produces the pain — this fear inhibits full movement, accelerates physical and psychological deterioration, and perpetuates the TrPs.

Clinical Examination

Postural Assessment

Observe the patient initially for:

  • Stooped, round-shouldered, head-forward posture
  • Abducted scapulae (viewed from behind)
  • Weak interscapular muscles

When the cheekbone is in the same vertical plane as the sternal notch, the head and neck are in erect position without muscular overload. See Concept:Postural_Considerations for the full postural assessment and correction protocol.

Range of Motion and Strength

TrPs in the pectoralis major cause minimal restriction of glenohumeral motion when the muscle is involved alone — the Hand-to-Shoulder-Blade Test is not a sensitive indicator for this muscle.

The more useful tests are:

  • Scapular adduction test: Have the patient place the back of the ipsilateral hand on the hip and move the elbow posteriorly. Restriction compared to the contralateral side indicates pectoral TrP involvement; production of interscapular pain is another indicator. Bilateral comparison is the most sensitive indicator when involvement is unilateral (which it seldom is in the pectorals).
  • Stretch range fan-wise (supine): Move the arm into horizontal abduction, lateral rotation, and elevation in the different fibre directions. A sensitive operator can feel the restriction of the involved taut band; the patient feels increased tension, often as local pain, in the involved section.
  • Strength testing (supine):
    • Clavicular and sternal sections: resist adduction at the glenohumeral joint with the arm held straight up
    • Costal and abdominal sections: resist adduction of the elevated arm obliquely downward toward the contralateral iliac crest

Cardiac Arrhythmia TrP Examination

This TrP produces no spontaneous pain and is found only by deliberate palpation in a patient with unexplained ectopic rhythm.

Locate the tip of the xiphoid process. At that level on the right side only, in a vertical line midway between the sternal border and the nipple line, press upward against the inferior edge of the fifth rib and explore the hollow between the fifth and sixth ribs for spot tenderness.

Breast Examination

When breast pain or nipple hypersensitivity is present, palpate the lateral free margin (anterior axillary fold) for TrPs in the costal section. Signs of lymphatic drainage impairment (slight breast enlargement, doughy texture) support the diagnosis — these resolve after TrP inactivation.

Differential Diagnosis

Cardiac

Feature Myofascial TrP (pectoralis major) Angina pectoris / ACS
Pain character Aching, muscular; reproduced precisely by TrP palpation Pressure, tightness, constriction; not reproducible by chest wall palpation
Activity relationship Variable day-to-day; inconsistent relationship to exertion Consistent threshold with exertion; predictable exercise response
Chest wall palpation Taut band, spot tenderness, local twitch response; familiar pain reproduced No taut band; diffuse or absent chest wall tenderness
Response to vapocoolant / local injection Relieves the TrP pain; does NOT modify ECG ischaemic response if true CAD coexists Vapocoolant to the referred pain area may relieve anginal pain without altering the ECG — so relief alone cannot exclude ischaemia
ECG / troponin Normal; noncardiac pain may induce transient T-wave changes Abnormal with active ischaemia
Response to nitrates Occasionally relieves (nitrates dilate peripheral vessels) Reliably relieves (though placebo sometimes equally effective)

Critical rule: A diagnosis of active myofascial TrPs with a dramatic response to local treatment does NOT exclude cardiac disease. The cardiac status must be established in every patient who experiences relief of chest pain by these measures. The conditions coexist.

Non-cardiac Chest Pain

Condition Key distinguishing features
Pectoralis minor TrPs Similar pain pattern; anatomically adjacent; almost always coexists — the uppermost sternal TrP lies at the three-way overlap of both muscles
Costochondritis / Tietze's syndrome Localised swelling and tenderness at costochondral junction; no taut band; may coexist
Chest wall syndrome / precordial catch / slipping rib / rib-tip syndrome Each has specific localising signs; all can be relieved by local injection — consistent with possible TrP origin; examine specifically for TrPs in each case
C5–C8 radiculopathy Dermatomal sensory changes; reflex changes; neurological examination abnormal
Intercostal neuritis / radiculopathy Dermatomal distribution; sharp/burning quality; aggravated by respiration
Hiatal hernia / oesophageal reflux / splenic flexure gas / lung cancer GI or respiratory symptoms; no taut band; investigations required
Fibromyalgia tender point at 2nd rib Tender points at sternocostal junction of 2nd rib may be confused with costochondritis or pectoralis major attachment TrPs — distinguish by identifying the taut band
Pseudo-thoracic outlet syndrome Pectoralis major is one of the four muscles comprising the myofascial pseudo-TOS quadrad (with latissimus dorsi, teres major, and subscapularis); individually and in combination these muscles produce referred pain confusingly mimicking TOS; a true compressive TOS (from scalene TrPs) may coexist
  • Pectoralis minor — co-active; similar pain pattern; medial pectoral nerve pierces it
  • Subclavius — almost invariably involved alongside clavicular section TrPs; examine specifically (see separate page)
  • Anterior deltoid — satellite TrP; lies within the pectoralis major pain reference zone; likely to develop first
  • Subscapularis and latissimus dorsi — synergistic unit; develop active TrPs in sequence
  • Serratus anterior, rhomboids, and middle trapezius — antagonists that develop painful stretch weakness from tense pectorals; rhomboids and middle trapezius can also develop latent TrPs activated by unaccustomed shortening during pectoral stretch — release with non-stretch procedures before strengthening
  • Infraspinatus, teres minor, posterior deltoid — with progressive restriction, these develop active TrPs leading to a frozen shoulder
  • SCM (clavicular head) — clavicular pectoral TrP shortening pulls the medial clavicle forward and downward, tensioning the clavicular head of the SCM and activating TrPs there with autonomic consequences

Trigger Point Examination

Palpate with the arm abducted to approximately 90° to place the muscle on moderate tension and maximise spot tenderness.

  • Clavicular section and parasternal fibres: flat palpation
  • Intermediate and lateral sternal and costal sections: pincer palpation — encircle the muscle fold between thumb and fingers; the lateral border of the pectoralis major is one of the easier muscles in which to identify nodules and taut bands. Local twitch responses are often highly visible.
  • Upper and midsternal sections (in patients with mobile subcutaneous tissue): pincer palpation by inserting the fingers between the underside of the muscle and the chest wall

The most reliable diagnostic criteria are: palpable taut band, spot tenderness within it, reproduction of the patient's familiar pain, and a local twitch response.

Entrapment

No direct nerve entrapments by the pectoralis major have been confirmed.

Lymphatic drainage from the breast may be entrapped by tense pectoral fibres (a lymph vessel from the cephalad breast may pierce the pectoralis major to reach subclavicular nodes), causing breast oedema that resolves with TrP inactivation.

Treatment

Postural Correction

Correction of round-shouldered posture is essential for lasting relief and must accompany all other treatment. See Concept:Postural_Considerations for the full protocol covering standing, sitting, lumbar support, and dynamic movement correction.

Spray and Stretch

See Apropos Treatment for general principles.

All sections are more effectively stretched with the patient seated than supine — seated position allows greater scapular and arm motion. Traction must be applied to the arm as part of the stretch. The subscapularis must also be released if its TrPs are limiting pectoral stretch; include its spray pattern alternately.

Check and treat the contralateral pectoralis major — both are frequently involved in round-shouldered posture.

  • Clavicular section: Arm laterally rotated and horizontally extended (abducted) slightly below 90°; spray swept laterally from the clavicle across the muscle, over the shoulder and upper limb
  • Intermediate sternal section: Arm at 90° abduction, laterally rotated, then moved slowly into extension; spray swept laterally and upward across the sternal portion, continuing over the upper limb including the fingers
  • Parasternal TrPs: Same stretch position; spray swept medially over the TrPs and pain reference zone to the midline
  • Lowest costal section: Arm flexed at shoulder in lateral rotation; spray directed downward and medially from the humerus, also covering the breast

Follow with three slow cycles of full active range of motion and moist heat.

Important caution: Vapocooling the skin over the pectoralis major may relieve the pain of true cardiac ischaemia as well as myofascial pain. The cardiac status must be known in every patient who experiences relief of chest pain by these measures.

Other Manual Techniques

Postisometric Relaxation (PIR), trigger point pressure release, and contract-relax techniques are effective for central TrPs. The primary approach to attachment TrPs (parasternal enthesopathy along the sternal border) is to inactivate the corresponding central TrPs.

Trigger Point Injection

See Trigger Point Injection for general principles.

The patient lies supine for all injections.

Critical safety principle: Needles directed over the thoracic cage must be aimed nearly tangent to the chest wall to avoid pneumothorax. This applies to the clavicular and mid/lower-sternal sections.

Clavicular section

Flat palpation; needle aimed cephalad and nearly tangent to the chest wall.

Upper sternal section

Flat palpation; injected in the region of the uppermost TrP. Pincer palpation may be used in patients with mobile subcutaneous tissue by inserting the fingers between the underside of the muscle and the chest wall.

Mid- and lower-sternal sections

Flat palpation; 37 mm (1.5 inch) needle directed upward toward the coracoid process, nearly parallel to the thoracic cage.

Parasternal attachment TrPs

Flat palpation; inject as for mid-sternal. Sustained relief requires inactivation of the corresponding central TrPs first.

Costal / lateral border section

Pincer palpation of the anterior axillary fold; needle directed perpendicularly for deep TrPs, at acute angle to fibres for superficial ones. Multiple TrPs may be reached through one skin penetration. Haemostasis by constant counterpressure during and after each injection.

Arrhythmia TrP (right side only)

Locate the precise spot tenderness by flat palpation between the fifth and sixth ribs on the right. Needle directed cephalad toward the fifth rib, aimed nearly tangential to the skin. This TrP lies no deeper than the anterior surface of the lower border of the fifth rib. Inactivate all sternal division TrPs before attempting the arrhythmia TrP. Teach the patient self-application of trigger point pressure release to abort paroxysmal ectopic tachycardia.

Post-injection: three slow cycles of full active range of motion; moist heat. Residual TrPs may be inactivated by trigger point pressure release and/or stretch and spray.

Corrective Actions

Patient Education — Cardiac Mimicry

For patients with no demonstrable cardiac disease who have been living with fear of a cardiac diagnosis: demonstrating that their familiar pain is reproduced precisely by TrP palpation, and showing local twitch responses, convinces patients that the pain is myofascial rather than life-threatening. This is clinically essential — the fear itself inhibits movement and perpetuates the TrPs. When coronary artery disease and pectoralis major TrPs coexist, relief of the TrP-induced pain is important for more than comfort, as pain itself may reflexly diminish coronary artery calibre.

Postural Reconditioning

See Concept:Postural_Considerations for the full standing, sitting, and movement protocol. Key practical points:

  • Shift body weight from heels onto the balls of the feet to restore cervical and lumbar curves effortlessly
  • Move the ischial tuberosities toward the front edge of the chair; one foot placed posteriorly
  • Lumbar roll at belt height for all prolonged sitting, including driving
  • Chair armrests at the height of the half-flexed elbow — absence of armrests causes the arms to cross in front of the chest, shortening the pectorals

Sleeping Posture

  • Avoid sleeping with arms folded across the chest
  • When lying on the pain-free side: support the uppermost forearm on a pillow to prevent the arm from dropping forward and shortening the affected pectoralis major
  • When lying on the affected side: tuck the pillow in the axilla between the arm and chest to maintain pectoral stretch
  • Corner of the pillow tucked between head and shoulder to drop the shoulder backward

In-doorway Stretch Exercise

Stand in a narrow doorway with the forearms flat against the door facings (do not grasp the doorjamb — this interferes with muscle relaxation). One foot forward with the forward knee bent. Shift the body through the doorway for a slow, gentle, passive bilateral stretch. Stretch only to the point of comfortable tension without pain. Hold briefly, relax, breathe slowly between cycles.

Hand position determines which section is stretched:

  • Lower hand position → clavicular section
  • Middle hand position (upper arms horizontal) → sternal section
  • Hands as high as possible → costal and abdominal sections

Bra Modification

Tight circumferential bra pressure aggravates and perpetuates costal section TrPs. Add a bra extender between the hooks, or reduce built-in elasticity by using a hot iron.

References

  • Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 42 (pp. 819–843).
  • Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1. 2nd ed. Chapter 41 (pp. 801–818).
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