A pectoralis-major strain and a major tendon tear can begin with the same event, but they do not require the same management. Bruising, visible deformity, loss of the anterior axillary fold and marked weakness increase concern for a structural tear. MRI of the chest can then define whether the injury is in the muscle, musculotendinous junction, tendon or humeral insertion.
What the imaging literature shows
Early MRI series
6 of 6
MRI agreed with surgery. 10 patients: 5 complete tears, 4 partial, 1 normal
PMID 10929411
Injury locations
5 sites
origin, muscle belly, musculotendinous junction, intratendinous, humeral insertion
PMID 28076015
Preferred imaging
Chest MRI
described as the gold standard for suspected pectoralis-major rupture
PMID 36589511
Small series and narrative reviews; imaging is used when the answer would change management.
A muscle with more than one part
The pectoralis major is not a uniform sheet of muscle. Its clavicular and sternocostal fibers converge toward a complex humeral tendon, and injury location can substantially change prognosis and treatment.
The clavicular head arises from the collarbone. The larger sternocostal head arises from the breastbone and upper ribs. Their fibers converge toward the front fold of the armpit, where muscle becomes tendon at the musculotendinous junction, and the tendon twists to insert on the upper humerus at the outer edge of the biceps groove. Together these fibers adduct the arm, bring it across the body, rotate it inward and help with shoulder flexion depending on arm position.
Recent anatomic work has refined how the distal tendon is described, which is one reason imaging these injuries can be difficult (Chiavaras, 2015).
Where pec injuries happen
A 2017 imaging review described pectoralis-major injury at the muscle origin, the muscle belly, the musculotendinous junction, within the tendon and at the humeral insertion, with or without bone avulsion. Tears range from partial to complete, and treatment may be surgical or conservative depending on the clinical scenario and the anatomy of the injury (Lee, 2017).
Modern imaging literature emphasizes that pectoralis-major injury can occur anywhere from the muscle belly to the humeral insertion. A generic label such as "pec strain" therefore does not describe the structural injury well enough for treatment planning.
Reviews also note that most tears occur near the tendon insertion (Haley, 2014), and that ruptures at the musculotendinous junction and within the muscle are more often caused by a direct blow (Petilon, 2005).
The bench-press mechanism
A sudden pop during the lowering phase of a heavy bench press, especially with bruising, weakness or loss of the anterior axillary contour, should raise concern for a significant pectoralis-major tear rather than routine post-training soreness.
Reviews describe the classic injury as eccentric loading with the arm extended and externally rotated, as at the bottom of a heavy press (Haley, 2014). A 2025 MRI guide adds that in this position the lowest sternal-head fibers are the shortest and most stretched, which predisposes them to tear, and that direct trauma, including occupational injuries, can also cause the injury (Lake, 2025). Pectoralis-major ruptures are uncommon but have become more frequent with the popularity of weight lifting (Long, 2022).
Signs that suggest a structural tear
People often describe a snap or pop followed by pain, weakness, swelling or deformity. On examination, reviews describe bruising, a palpable defect, thinning or asymmetric webbing of the anterior axillary fold and weakness on resisted shoulder adduction and internal rotation (Petilon, 2005; Long, 2022).
Complete tears often change the contour of the anterior axillary fold and produce measurable weakness in shoulder adduction and internal rotation. Swelling can hide a defect in the first days, so the contour is compared again once swelling settles.
Strain, partial tear or complete tear
| Feature | Muscle strain / low grade | Partial tear | Complete tear / avulsion |
|---|---|---|---|
| Onset | Pain during or after training | Pain, sometimes a pop | Pop with sudden pain |
| Bruising | Usually minimal | Possible | Common |
| Contour | Normal | Uncertain | Changed, with axillary fold asymmetry |
| Strength | Largely preserved | Weak or painful | Substantial weakness |
| Course | Improves steadily | May persist under load | Possible tendon retraction |
The examination does not perfectly grade a tear. Swelling, pain and guarding can make a partial tear look complete, or a complete tear look smaller than it is. That is why imaging matters when a significant tear is possible.
Why chest MRI, not shoulder MRI
For suspected significant pectoralis-major injury, MRI of the chest, not a routine shoulder MRI, is generally the preferred study because it better captures the full pectoralis muscle-tendon unit. A 2022 review described MRI of the chest as the gold standard (Long, 2022), and a 2025 guide noted that chest MRI protocols tailored to include the origin and insertion have been described (Lake, 2025).
A routine shoulder MRI is designed around the rotator cuff and joint. It may show the humeral insertion but miss the muscle and the extent of retraction. A shoulder MRI alone may not be enough to evaluate a suspected pectoralis tear.
Not every pectoralis injury needs MRI. A mild strain with preserved strength, normal contour and steady improvement usually does not.
What the early MRI series showed
In an early MRI series of 10 suspected pectoralis-major injuries, MRI identified complete and partial tears and agreed with operative findings in all six patients who underwent surgery. The scans showed five complete tears, four partial tears and one normal tendon. Two injuries were at the myotendinous junction and seven at the enthesis, where tendon meets bone. The four patients managed without surgery improved, with function and strength consistent with a healed partial injury (Carrino, 2000).
This was a small retrospective series. It supports MRI as useful for detecting and grading these tears, not a precise accuracy figure.
What a 2025 MRI guide adds
A 2025 radiology review reinforces that accurate MRI characterization depends on identifying the exact injured layer, tendon component and degree of retraction rather than simply labeling the scan "pectoralis tear." The authors noted that the complex and variable anatomy makes a single standardized classification difficult, that there is no consensus on what defines an acute versus chronic injury, and that acute swelling can obscure a retracted tendon. They recommended clear communication between surgeons and radiologists about what the report needs to answer, because MRI diagnosis can avoid surgical delay (Lake, 2025).
For surgical planning, the key questions are which head is torn, where along the unit the tear sits, whether it is partial or complete, and how far the tendon has retracted.
Where ultrasound fits
High-resolution ultrasound can visualize many pectoralis-major injuries dynamically, but complex partial tears and deep anatomy may still require MRI for complete characterization. In skilled hands it can show tendon continuity, muscle injury and hematoma, compare both sides and watch the tissue move. Imaging reviews emphasize that the regional anatomy is complex, so experience and a systematic approach matter (Chiavaras, 2015; Lee, 2017).
Surgery or not
Treatment depends on tear location, completeness, retraction and patient demand. Complete distal tears in active patients commonly receive surgical consultation because restoring strength and contour can be difficult with nonoperative care alone.
Reviews generally reserve nonoperative treatment for proximal tears in the muscle, low-grade partial tears and older or lower-demand patients, and note that most of those patients return to full daily activities. For other tears, especially in young, active athletes, acute repair within about six weeks is recommended to restore strength and function (Haley, 2014). Other reviews report better functional outcomes, appearance and satisfaction with repair in appropriate patients (Long, 2022; Petilon, 2005).
Significant complete tears should be referred promptly because acute repair is generally technically easier than delayed reconstruction. That is not an absolute deadline, and not every tear needs surgery.
Partial tears and chronic pain
Selected partial tears and chronic strains can be managed conservatively. Care usually combines progressive strengthening, graded pressing and horizontal adduction work. Manual treatment may help improve tissue mobility and mechanical tolerance in chronic post-injury presentations, but it does not substitute for structural repair when a tendon is significantly disrupted. Shockwave is considered only when chronic symptomatic tissue remains and major structural disruption has been excluded. See shockwave therapy for pectoralis major injury.
Rehabilitation
Rehabilitation progresses according to the injury and the response to load:
- Pain-controlled range of motion
- Isometric adduction
- Horizontal adduction loading
- Internal-rotation strengthening
- Push-up progression, then cable and dumbbell pressing
- Bench-press progression
- Sport-specific force and speed
There is no single fixed timeline. After surgery, the surgeon's protocol sets the early limits.
Returning to Pressing After a Pec Injury
Return to bench press should be based on restored capacity and eccentric control rather than simply waiting a fixed number of weeks. Before heavy pressing, we look at:
- Pain during and after loading
- Adduction and horizontal-adduction strength compared with the other side
- Internal-rotation strength
- Control of the lowering phase
- Tolerance of progressive pressing volume
- Symmetry of contour and movement
- Confidence and the demands of the sport or job
Many lifters return first with dumbbells or a reduced range before full barbell depth.
Not every chest injury is the pectoralis major
Pain at the front of the shoulder can come from the rotator cuff or biceps, and arm tingling can come from the neck. The deeper pectoralis minor is a separate diagnosis that can involve neurovascular compression; see pectoralis minor syndrome vs. shoulder and chest pain. New chest pressure, shortness of breath, sweating, fainting or other cardiopulmonary symptoms should not be treated as a routine muscle injury.
How Novo approaches a pec injury
We screen for cardiopulmonary warning signs, take the injury history, compare contour and the anterior axillary fold, test adduction, horizontal adduction and internal rotation, and screen the shoulder, biceps and neck. When a significant tear is possible, we arrange chest MRI or ultrasound and refer promptly. See how we approach pectoralis major, pectoralis minor and anterior chest pain.
References
- Carrino JA, Chandnanni VP, Mitchell DB, Choi-Chinn K, DeBerardino TM, Miller MD. Pectoralis major muscle and tendon tears: diagnosis and grading using magnetic resonance imaging. Skeletal Radiology. 2000;29(6):305-313. PMID 10929411. (link)
- Lee YK, Skalski MR, White EA, et al. US and MR imaging of pectoralis major injuries. RadioGraphics. 2017;37(1):176-189. PMID 28076015. (link)
- Chiavaras MM, Jacobson JA, Smith J, Dahm DL. Pectoralis major tears: anatomy, classification, and diagnosis with ultrasound and MR imaging. Skeletal Radiology. 2015;44(2):157-164. PMID 25200915. (link)
- Lake MG, Skalski MR, Chiu MK, et al. Magnetic resonance imaging of pectoralis major injuries: a radiologist's essential guide. Emergency Radiology. 2025;32(5):797-807. PMID 40772985. (link)
- Long MK, Ward T, DiVella M, Enders T, Ruotolo C. Injuries of the pectoralis major: diagnosis and management. Orthopedic Reviews. 2022;14(4):36984. PMID 36589511. (link)
- Haley CA, Zacchilli MA. Pectoralis major injuries: evaluation and treatment. Clinics in Sports Medicine. 2014;33(4):739-756. PMID 25280620. (link)
- Petilon J, Carr DR, Sekiya JK, Unger DV. Pectoralis major muscle injuries: evaluation and management. Journal of the American Academy of Orthopaedic Surgeons. 2005;13(1):59-68. PMID 15712983. (link)
