Trapezius

The Trapezius is an extensive superficial back muscle that spans from the Cranium to the lowest segment of the Thoracic Spine and as lateral as the Acromion of the Scapula . Its large stature implicates its role in the function of several body regions including The Shoulder Girdle , Cervical Spine , Thoracic Spine and Cranium .

Structure

The Trapezius is a four-point star shaped muscle that comprises the most superficial layer of the upper back. The direction of its fibres distinguish its three sections (SOURCE-17+30+38):

  • Superior Fibres akaUpper Trapezius- arise from the medial third of the Superior Nuchal Line and Nuchal Ligament ( C1 - Atlas - C6 ) and course in a inferolateral direction towards their insertion on the lateral portion of the Clavicle on its posterior border and Acromion of Scapula

  • Middle Fibres - arise from the Spinous Processes of C7-T4 and the associated Supraspinous Ligaments and courses laterally towards its insertion onto the medial Acromion and Spine of Scapula

  • Inferior Fibres akaLower Trapezius- arise from the Spinous Processes of T4-T12 and their Supraspinous Ligaments and course anterolaterally towards its insertion (via an aponeurosis) on a Tubercle found on the medial end of the Spine of Scapula

Innervation

The Trapezius receives motor innervation from Cranial Nerve XI as well as afferent (sensory) fibres from the anterior rami of C3 , C4 and on occasion C2 - Axis (SOURCE-13+17+38). It is the only upper body muscle not to receive nervous innervation via the Brachial Plexus .

Fibre Type

The Muscle Fibre Type composition appears similar in males and females, with a predominance of Type I Fibres (SOURCE-11). Type II Fibres did, however, occur more frequently in the Upper Fibres (SOURCE-11). This is consistent with the perspective that the Trapezius’ primary role relates to posture of the upper axial skeleton.

Muscle Architecture

The Muscle Architecture of the multipennate Trapezius varies greatly between its three distinct portions and to a lesser extent within them. This diverse architecture is a reflection of its expansive function in movement and stability. One such variable marker is thePhysiologic Cross-Sectional Area (PCSA). The middle (transverse) fibres account for roughly half of the Trapezius’ total PCSA, while the lower (ascending) fibres generally account for a larger proportion of the remaining total PCSA than the upper (descending) fibres (SOURCE-18+19). In terms of fibre length, the Lower Trapezius appears to consistently have the longest fibres while both the Middle and Upper Trapezius fibres have been reported to be the shortest (SOURCE-18+19). This inconsistency may be explained by sampling differences, as superficial fascicles of the Middle Trapezius, for example, may almost span the entire length of a muscle while deeper fascicles were found to be shorter (SOURCE-18). The pennation angle is also variable. Fibres of the Middle Trapezius have the lowest pennation angle, with nearly parallel fibres on their lateral course towards the Acromion. Conversely, the Lower Trapezius appears to have the most angulation, although both the Upper and Lower Trapezius have been shown to vary greatly (SOURCE-18+19). While certain metrics are heavily contingent on the population evaluated and measurement methodology, the following has been reported (Upper/ Middle/ Lower Fibres):10 human cadavers (SOURCE-18):

  • Mean Fascicle Length - 84 ± 21mm/ 92 ± 18mm/ 123 ± 16mm

  • Mean Pennation Angle - 0-70º/ 0-10º/ 10-75º

  • Mean PCSA - 1.96 ± 0.62cm²/ 10.77 ± 2.38cm²/ 3.89 ± 0.82cm²

8608 fibre bundles from Four (2m, 2F) Cadavers/ 8 Trapezius’ (SOURCE-19):

  • Mean Pennation Angle - 10.36º (10.04-10.67 range)/ 7.06º (6.93-7.18)/ 16.83º (16.47-17.20)

  • Mean Volume (as a proportion) - 26.74% (19.79–33.69 range)/ 40.34% (37.38–43.30)/ 32.92% (27.08–38.75)

  • Mean PCSA (as a proportion) - 23.59% (17.23–29.96 range)/ 48.43% (45.38–51.48)/ 27.98% (23.01–32.95)

Androgen Receptors

The Trapezius appears to have a higher expression of androgen receptors when compared to the Vastus Lateralis . This expression is exacerbated with resistance training and anabolic steroids (SOURCE-14).

Variation

The Trapezius is described to have a relatively large morphological diversity, yet there is a paucity of literature regarding the topic (SOURCE-39). The Clavicular attachment varies, sometimes extending to the Mid- Clavicle or blending with the Sternocleidomastoid (SOURCE-17). The cervical and dorsal portions are occasionally seperate, the inferior part may be absent, hypoplastic or terminate at T8 (SOURCE-17).

Function

At a quick glimpse the muscle is capable of Cervical - Extension when bilaterally contracted and ipsilateral Cervical - Lateral Flexion or contralateral Cervical - Rotation when unilaterally contracted. In terms of relations, the Middle and Lower fibre of the Trapezius are a major contributor to the Pull group of muscles. Given the vast and unique structure of the muscle, there are multiple portions with distinct fibre orientations that result in differing functions:

Upper Trapezius

The primary action of the upper fibres is Scapulothoracic Joint - Elevation , however, these fibres can also draw the Upper Cervical Spine in the direction of the Scapula through either:

In addition they provide postural support to The Shoulder Girdle (particularly Scapula and Clavicle ). Attachment of the Upper Trapezius to the lateral end of the Clavicle provides excellent leverage about the Sternoclavicular Joint for maintaining the slight elevation and retraction needed to facilitate the important upward tilt of the Glenoid Fossa (SOURCE-8).Activity of the Upper Trapezius increases with elevation in a non-proportional fashion. During Scaption (arm elevation in the Scapula plane) activity of the Upper fibres progressively increases between 0-60º, maintains activity between 60-120º and then progressively climbs again between 120-180º (SOURCE-7). Returning the arm to the anatomical position is complimented by rotation of the Scapula (SOURCE-17). Typically gravity and the lengthening Trapezius and Serratus Anterior are sufficient to control this movement, however when larger forces are required the Levator Scapulae and Rhomboids are recruited with small initial contributions from the Pectoralis Minor (SOURCE-17)

Middle Trapezius

The horizontal orientation of the middle fibres draw the Scapula towards the Vertebral Column , facilitating Scapulothoracic Joint - Retraction . Consequently these fibres act as a stabiliser for the Scapula during movements such Scapulothoracic Joint - Protraction and Scapulothoracic Joint - Upward Rotation .

Lower Trapezius

The anteriolaterally directed fibres of the Lower Trapezius draw the medial aspect of the Spine of the Scapula distally, causing Scapulothoracic Joint - Upward Rotation . In synergistic fashion, the Serratus Anterior complements rotation about this axis by pulling the Scapula laterally and superiorly via its multiple attachments. During arm elevation, these fibres also aid External Rotation and Posterior Scapular Tilting (SOURCE-2+7).

Pathomechanics

The onset of Trapezius related pathology typically occurs by traumatic or insidious means. In either instance, the consequences of Trapezius insufficiency share a similar narrative. Of the Scapulothoracic Joint , the Serratus Anterior and Middle and Lower Trapezius are the most frequently inhibited or weak which is thought to be a notable factor in the pathogenesis of several shoulder pathologies (SOURCE-1+26+28). Given the Scapulothoracic Joint - Upward Rotation force-coupling formed between the Serratus Anterior and Lower Trapezius, this prevalent insufficiency leads to decreased elevation of the Acromion, consequent disturbance to Scapulohumeral Rhythm and a sequelae which includes (SOURCE-1+26+28):

Traumatic

The robust stature of the Trapezius relative to the many vulnerable neighbouring soft-tissues makes it not often a focal point of traumatic injury. The Upper fibres and their fascial attachments are however implicated to varying extents in Dislocation of the Acromioclavicular Joint . More severe forms of joint injury (particularly types III+) compromise the Trapezius attachment from the lateral Clavicle and/ or have the Clavicle perforate through the muscle belly.Trapezius dysfunction or paralysis is most often neurogenic and related to Cranial Nerve XI as it takes a vulnerable superficial course through thePosterior Cervical Triangle(posterior triangle of neck) (SOIRCE-35+38). While injury may be caused by blunt trauma like those from contact sports, the most frequent cause is iatrogenic nerve injury from surgical procedures that involve the Posterior Cervical Triangle (SOURCE-35+38)

Insidious

Capacity of the Trapezius can diminish through processes unrelated to acute trauma:

  • Sustained Postures - prolonged static postures or particular repetitive movements affect the length-tension relationship of the Trapezius which acutely alters it activity and chronically may lead to morphological or physiological tissue changes (SOURCE-32). Forward Head Posture reduces the contributions of most neck Muscles during protraction/ retraction of the head, including the Middle Trapezius (SOURCE-33). The slouched posture associated with Thoracic Spine Kyphosis was shown to increase activity in the Middle and Lower Trapezius, leading to overactivity at rest and during motions such as arm elevation, leading to fatigue and possible Pain (SOURCE-34).Trapezius Myalgia, a common musculoskeletal condition characterised by Pain , stiffness and muscle tightness is associated with poor posture or repetitive movements (SOURCE-32). This condition often displays “moth-eaten” fibres, a sign of disturbed local oxygen metabolism, with a higher prevalence in particular highly repetitious professions such as cleaning (SOURCE-32). In a similar fashion poor posture or repetitive movement through traction or compression may irritate Cranial Nerve XI , with Trapezius dysfunction or paralysis most often of neurogenic cause (SOURCE-35)

  • Compensation – the Trapezius frequently compensates for weakness or dysfunction in neighbouring muscles, dramatically influencing its workload and pathomechanics. The Upper Trapezius often becomes a primary compensator, exhibiting an activity pattern that is inversely proportional to the Serratus Anterior (SOURCE-26). This substitution may alter the Scapula pivot point, promoting Scapulothoracic Joint - Elevation rather than Scapulothoracic Joint - Upward Rotation and Posterior Scapular Tilting , as seen in Secondary Subacromial Impingement . Additionally, increased Upper Trapezius activity during arm elevation is a common response to Rotator Cuff insufficiency (SOURCE-36). In this sense the Upper Trapezius appears to serve as a superficial global stabiliser for The Shoulder Girdle . Rotator Cuff insufficiency may also perpetuate postural fatigue of the Middle and Lower Trapezius (as described above) as it is often associated with pathological postures such as Anterior Scapular Tilting and Internal Rotation (SOURCE-36). The heightened workload derived from these compensatory patterns has the capacity to exacerbate acute or chronic injury to the Trapezius itself and may transform normally non-harmful stimuli into noxious ones

  • Cognitive Stress - although the precise mechanisms are poorly understood, unlike most skeletal Muscles the Trapezius receives innervation from more direct means via Cranial Nerve XI rather than indirectly via the Spinal Cord . This may serve as a plausible reason for why the Trapezius appears to have a notable association with cognitive stress. Additionally, mental and physical stress appears to activate the same motor units in the Upper Trapezius which affords a link between physiological and physical manifestation (SOUTCE-25). Electromyography (EMG) sensors placed on the Trapezius revealed higher muscle activity during cognitive stress periods including the anticipation of physical stimulus, in response to nociceptive stimulus ( Pain ) and post-stimulus (SOURCE-23+24). Conversely, activity levels appeared lower during rest and mediation (SOURCE-23). This heightened state of activity may come at the expense of muscular fatigue as there is an almost linear relationship between fatigue of the Upper Trapezius and increased mental demand (SOURCE-25). Affected fatigue parameters included endurance time and rate of fatigue (SOURCE-25)

Entrapment Sites

The upper fibres of the Trapezius are a known entrapment site for the Greater and Third Occipital Nerves .

Fascia

In terms of Fascia l connections, the Trapezius has been included in the following:

A restriction at any point along the line/ chain could result in Pain or dysfunction of the Trapezius.

Referred Pain

The accumulation of myofascial trigger points or Inflammation within the Trapezius may result in Referred Pain , with each portion producing a distinct referral pattern (SOURCE-20):

  • Upper Fibres - Pain and/ or tenderness on its course along the posterolateral neck or referred to the angle of the Mandible or temporal region

  • Middle Fibres - pain local to the muscle fibres that may radiate towards the spine

  • Lower Fibres - pain may refer to posterior Cervical Spine , Mastoid region and superior Spine of Scapula

Muscle weakness may also be of relatable detriment as the vast majoirty of those with unilateral neck Pain were shown to have am insufficient Lower Trapezius (SOURCE-31).

Pathology

With its extensive attachments and Muscle -couplings, the Trapezius is related to many pathologies of The Shoulder Girdle . Its pathologic state may predispose many pathologies or vice versa:

Subacromial Impingement - the relationship shared between this condition and the Trapezius is multifactorial and contingent on the fibre orientation. Given their ability to posteriorly tilt the Scapula , the Lower fibres may decrease the risk of impingement (SOURCE-2), while disturbed recruitment of the Upper and Middle fibres is often displayed in symptomatic shoulders (SOURCE-2). This is supported by the significantly higher Upper Trapezius activity and lower activity of the Middle and Lower Trapezius displayed in those with impingement (SOURCE-28). In some instances those with impingment displayed an increase of Lower Trapezius activity although this is not as reproducible and may be a compensatory response to reduced activity of the Serratus Anterior (SOURCE-28). In addition to weakness, there appears a delayed response of the Middle and Lower Trapezius during sudden downwards arm movement, which may also perpetuate impingement mechanisms (SOURCE-28).

Adhesive Capsulitis - Middle and Lower Trapezius exercises have improved symptoms of Adhesive Capsulitis including Pain , range of motion and function (SOURCE-4+5). Further, the condition has been associated with excessive activity in the upper fibres, suggesting that the pathomechanics derived from abnormal Trapezius tone my play a role in the onset or maintenance of the condition (SOURCE-5).

Scapular Dyskinesis - shortened Upper Trapezius fibres are highly associated with pathomechanics of the Scapula , one study finding those with shortened Upper fibres to be over 2x more likely to experience Scapular Dyskinesis. (SOURCE-6). Similar relations are displayed on Electromyogram (EMG) data, where excessive activity of the Upper Trapezius relative to the Lower Trapezius and Serratus Anterior was related to altered Scapula kinematics (SOURCE-26+28). Lower Trapezius activity is assocaited with prominence of the Medial Border and Inferior Angle of Scapula (SOURCE-26). Higher activity of the Upper Trapezius appears to be inversely proportional to activity of the Serratus Anterior (SOURCE-26). While less a point of focus, weakness of the Middle Trapezius has also been associated with Dyskinesis (SOURCE-28)

Thoracic Outlet Syndrome - both insufficiency and excessive tone/size of the Trapezius has been described to encroach on the Thoracic Outlet and increase pressure on the contained neurovascular structures, leading to the TOS. Upper Trapezius insufficiency may cause the shoulder to depress which can structurally imdede on the outlet (SOURCE-27). Conversely, with the attachment of the Upper fibres on the Distal Clavicle (a border of the outlet), hypertonicty and/ or hypertrophy may lead to a superoposterior pull which hypothetically narrows the Costoclavicular Space of the Thoracic Outlet (SOURCE-29)

Headaches - in a hypertonic state (with many active “Trigger Points (TrPs)”) the Trapezius may reproduce symptoms akin to those described for Tension-Type Headaches . Stimulation of active TrPs in the Upper Trapezius was shown to reproduce symptoms for a considerable portion of those with Chronic Tension-Type Headaches (SOURCE-40). The intensity of headache symptoms appears to be related to the TrP activity (SOURCE-40).

Acromioclavicular Joint Dislocation - more severe forms of joint injury (particularly types III+) comprise the Trapezius attachment from the lateral Clavicle and/ or have the Clavicle perforate through the muscle belly.

Assessment

Observation

  • Upper Trapezius Atrophy - may indicate palsy of Cranial Nerve XI (SOURCE-9)

  • Scapula - Medial Border or Inferior Angle prominence could be suggestive of Lower Trapezius weakness (SOURCE-26). Increased distance between Spinous Process and Medial Border when compared to asymptomatic side (SOURCE-38)

Range of Motion

The following Range of Motions may be Pain ful or weak in the case of Trapezius pathology:

Strength Testing

The following active resisted motions can be used to evaluate the relative strength of the various Trapezius fibres. These tests are similar but distinct of the Trapezius Test .

  • Upper Trapezius - with the force of gravity being the distinguishing feature, the Upper Trapezius may be evaluated with the patient in either a seated (with gravity) or prone (without gravity) position (SOURCE-12). The therapist must use their palpation to distinguish between fibres of the Upper Trapezius and the anteriorly positioned Levator Scapulae as they share resistance testing (SOURCE-12). In either position the patient performs Scapulothoracic Joint - Elevation against the resistance of the practitioner by raising their shoulders towards their ears

  • Middle Trapezius - with the force of gravity yet again being the main consideration between seated or prone, the seated variation is more appropriate for those with significant reductions in muscle performance (SOURCE-12). In either position, the patient performs a Prone Horizontal Abduction / Full Can -like motion against the resistance of the practitioner while the medial fibres are simultaneously palpated for activity

  • Lower Trapezius - patient is ideally prone with contralateral Cervical - Rotation and 130º GH Joint - Abduction . Therapist stabilises the patients Scapula with their hands and resists their Scapulothoracic Joint - Upward Rotation force (SOURCE-12). Patient attempts to raise arm towards the ceiling.

Palpation

As most superficial muscle of the posterior neck and upper back, the Trapezius is easily palpable. Distinguishing between the three major fibre orientations can be done with added resisted Active Range of Motion :

Neurological

Relevant neurological assessments for the Trapezius focus primarily on its motor supply ( Cranial Nerve XI ) and sensory/ reflex innervation of C3 - C4 :

Imaging

The following imaging modalities may be relevant in the evaluation of the Trapezius:Ultrasonography (Ultrasound)- the most cost-effective and accessible imaging modality available to the Trapezius that allows for the real-time dynamic assessment of soft-tissue. Tissues may be evaluated for morphometric features, stiffness and blood supply with B-mode ultrasound images reliably and objectively able to distinguish between the healthy Trapezius and those with myofascia pain syndrome (SOURCE-41+42).Magnetic Resonance Imaging (MRI)- provides clear images of the Muscle , Fascia and related nerves to evaluate structural damage or potential neurogenic causes of pathology. The MRI is considered the gold-standard for determining Trapezius muscle thickness (SOURCE-22). May also be used to distinguish between muscle atrophy and edema and rule out other differentials (SOURCE-38)Radiography (X-Ray)- while not a common modality used for the evaluation of the Trapezius as it provides images of osseous structures, an X-Ray may reveal subtle signs of muscle palsy. This includes a lateral drift of the Scapula and less overlap between the Scapula and the chest (SOURCE-38).

Treatment

The treatment of Trapezius pathology can be applied directly to the tissue or indirectly through its associated Fascia l and nervous structures.

Stretching

Stretching is not often as simple as targeting the muscle that is perceived to be tight. For tight feeling Pulling muscles such as the Trapezius, restoring length to antagonistic muscles such as those included in Push may be more valuable, particularly as Pain or disability reaches chronicity. With that in mind, the following lists all stretching techniques that lengthen at least a portion of the Trapezius:

Myofascial Release

Self-Guided:

Practitioner Guided:

  • Active Release Therapy - deep pressure is applied through the digit over the tender point of the Trapezius while the muscle is in a shortened position. While pressure is maintained, the patient actively moves to elongate the muscle. This technique has displayed significant reduction in multiple symptoms associated with Trapezius spasm (SOURCE-15)

  • Myofascial Release - a slow superficial glide is applied along the surface of the Trapezius. This technique has displayed significant reduction in multiple symptoms associated with Trapezius spasm (SOURCE-15)

Strengthening

The multidirectional fibres of the Trapezius contract through many motions or actions of The Shoulder Girdle . Contractile activity may serve to produce motion or play a stabilisation role by resisting it. Often early phase rehabilitation of the Trapezius involves lowering tone of the upper fibres and/ or increasing tone of the middle and lower fibres (SOURCE-10). For Push motions, the upper fibres of the Trapezius are considerably more active as verticality increases (SOURCE-21). The following exercises may be used to improve strength or functionality of the Trapezius (SOURCE-37+others):

Initial Phase:

Mid Phase:

Late Phase:

Dry Needling

Dry Needling of the Trapezius is performed differently for each segment.Starting Position:

  • Patient is prone or side-lying

  • Therapist palpates the intercostal spaces with two fingers (for middle and lower fibres)

Procedure:

  • Needle is inserted perpendicular to the skin in either an Anterior-to-Posterior direction or vice versa using a pincer grip

  • Needle is kept between the:

    • pincer grip (for upper fibres)

    • Fingers (for middle and lower fibres) to use the Rib as a bony block

Precautions:

  • Penetrating The Lungs - causing pneumothorax. Prevented by KEEPING NEEDLE BETWEEN PRACTITIONERS GRIP

  • Lower and Middle Fibres should be needled in a medial-to-lateral direction at a shallow angle (10-15º)

Breathing

Various Breathing patterns may used to improve or hinder specific Muscle properties of the Trapezius such as tension, stiffness and elasticity. A study with small samples with relatively poor intervention control found the following (SOURCE-16):

  • Thoracic (Chest) Breathing

    • Increased tension and stiffness in the Lower Trapezius while decreasing elasticity

    • Decreased tension and stiffness in the Upper Trapezius

  • Abdominal (Belly) Breathing

    • Decreased tension and stiffness in both the Upper and Lower Trapezius while increasing elasticity

References

  1. Paine, R., & Voight, M. L. (2013). The role of the scapula. International journal of sports physical therapy, 8(5), 617–629.

  2. Park, S.-y., & Yoo, W.-g. (2011). Differential activation of parts of the serratus anterior muscle during push-up variations on stable and unstable bases of support. Journal of Electromyography and Kinesiology, 21(5), 861–867. https://doi.org/10.1016/j.jelekin.2011.07.001

  3. Wilke, J., & Krause, F. (2019). Myofascial chains of the upper limb: A systematic review of anatomical studies. Clinical anatomy (New York, N.Y.), 32(7), 934–940. https://doi.org/10.1002/ca.23424

  4. Shabbir, R., Arsh, A., Darain, H., & Aziz, S. (2021). Effectiveness of proprioceptive training and conventional physical therapy in treating adhesive capsulitis. Pakistan journal of medical sciences, 37(4), 1196–1200. https://doi.org/10.12669/pjms.37.4.3874

  5. Abd Elhamed, H. B., Koura, G. M., Hamada, H. A., & Mohamed, Y. (2018). Effect of strengthening lower trapezius muscle on scapular tipping in patients with diabetic frozen shoulder: A randomized controlled study. Biomedical Research, 29(3), 442–447. https://doi.org/10.4066/biomedicalresearch.29-17-2367

  6. Yeşilyaprak, S. S., Yüksel, E., & Kalkan, S. (2016). Influence of pectoralis minor and upper trapezius lengths on observable scapular dyskinesis. Physical Therapy in Sport, 19, 7–13. https://doi.org/10.1016/j.ptsp.2015.08.002

  7. Escamilla, R. F., Yamashiro, K., Paulos, L., & Andrews, J. R. (2009). Shoulder muscle activity and function in common shoulder rehabilitation exercises. Sports Medicine, 39(8), 663–685.

  8. Neumann, D. A. (2002). Kinesiology of the musculoskeletal system: Foundations for physical rehabilitation (1st ed.). Mosby.

  9. Magee, D. J. (2014). Orthopedic physical assessment (6th ed.). Saunders.

  10. Adachi G, Oshikawa T, Akuzawa H, Kaneoka K. Muscle Activity During Scapular Muscle Exercises With Multijoint Compound Movement: Analysis Using Fine-Wire and Surface Electrodes. Orthopaedic Journal of Sports Medicine. 2022;10(11). doi:10.1177/23259671221132194

  11. Lindman, R., Eriksson, A., & Thornell, L.-E. (1991). Fiber type composition of the human female trapezius muscle: Enzyme-histochemical characteristics. *American Journal of Anatomy*, *190*(4), 385–392. ~[https://doi.org/10.1002/aja.1001900406](https://doi.org/10.1002/aja.1001900406

  12. Clarkson, H. M. (2013). Musculoskeletal Assessment: Joint range of motion and manual muscle strength. (3rd ed.). Lippincott Williams & Wilkins.

  13. Waxenbaum, J. A., Reddy, V., & Bordoni, B. (2025). Anatomy, head and neck: Cervical nerves. In StatPearls. StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK538136/

  14. Kadi, F., Bonnerud, P., Eriksson, A. et al. The expression of androgen receptors in human neck and limb muscles: effects of training and self-administration of androgenic-anabolic steroids. Histochemistry 113, 25–29 (2000). https://doi.org/10.1007/s004180050

  15. Mishra, D., Prakash, R. H., Mehta, J., & Dhaduk, A. (2018). Comparative study of active release technique and myofascial release technique in treatment of patients with upper trapezius spasm. Journal of Clinical and Diagnostic Research, 12(11), YC01–YC05. https://doi.org/10.7860/JCDR/2018/37558.12218

  16. Koo, D.-J., Park, S.-C., Park, J.-Y., Jung, J.-W., & Kwon, H.-G. (2024). Effect of breathing technique-based exercises on alignment and mechanical properties of muscles related to upper cross syndrome. Journal of the Korean Society of Physical Medicine, 19(4), 21–33. https://doi.org/10.13066/kspm.2024.19.4.21

  17. Standring, S. (Ed.). (2016). Gray’s anatomy: The anatomical basis of clinical practice (41st ed.). Elsevier.

  18. Kamibayashi, L., & Richmond, F.J. (1998). Morphometry of Human Neck Muscles. Spine, 23, 1314–1323.

  19. Stiver, M. L. (2022). Three-dimensional architectural and structural properties of the human trapezius muscle: Missing links in musculoskeletal research [Unpublished doctoral dissertation]. University of Toronto.

  20. Niel-Asher, S. (2008). The concise book of trigger points (2nd ed.). North Atlantic Books and Lotus Publishing.

  21. Luczak, J., Bosak, A., & Riemann, B. L. (2013). Shoulder muscle activation of novice and resistance trained women during variations of dumbbell press exercises. Journal of Sports Medicine, 2013, Article 612650. https://doi.org/10.1155/2013/612650

  22. O'Sullivan, C., Meaney, J., Boyle, G., Gormley, J., & Stokes, M. (2009). The validity of Rehabilitative Ultrasound Imaging for measurement of trapezius muscle thickness. Manual therapy, 14(5), 572–578. https://doi.org/10.1016/j.math.2008.12.005

  23. Ahmed, M., Grillo, M., Taebi, A., Kaya, M., & Thibbotuwawa Gamage, P. (2024). A Comprehensive Analysis of Trapezius Muscle EMG Activity in Relation to Stress and Meditation. BioMedInformatics, 4(2), 1047-1058. https://doi.org/10.3390/biomedinformatics4020058

  24. Luijcks R, Hermens HJ, Bodar L, Vossen CJ, Os Jv, Lousberg R (2014) Experimentally Induced Stress Validated by EMG Activity. PLoS ONE 9(4): e95215. https://doi.org/10.1371/journal.pone.0095215

  25. Deeney, C., & O'Sullivan, L. W. (2017). Effects of cognitive loading and force on upper trapezius fatigue. Occupational medicine (Oxford, England), 67(9), 678–683. https://doi.org/10.1093/occmed/kqx157

  26. Huang, T. S., Ou, H. L., Huang, C. Y., & Lin, J. J. (2015). Specific kinematics and associated muscle activation in individuals with scapular dyskinesis. Journal of shoulder and elbow surgery, 24(8), 1227–1234. https://doi.org/10.1016/j.jse.2014.12.022

  27. Kaplan, J., & Kanwal, A. (2023). Thoracic outlet syndrome. In StatPearls. StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK557450/

  28. Page P. (2011). Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes. International journal of sports physical therapy, 6(1), 51–58.

  29. Philp, J., Jeong, W. J., & Paily, P. (2024). An Uncommon Culprit: Trapezius Dystonia as a Cause of Thoracic Outlet Syndrome: A Case Report. Cureus, 16(7), e63825. https://doi.org/10.7759/cureus.63825

  30. Ourieff, J., Scheckel, B., & Agarwal, A. (2023). Anatomy, back, trapezius. In StatPearls. StatPearls Publishing. Retrieved from https://europepmc.org/article/NBK/nbk518994

  31. Petersen, S. M., & Wyatt, S. N. (2011). Lower trapezius muscle strength in individuals with unilateral neck pain. Journal of Orthopaedic & Sports Physical Therapy, 41(4), 260–265. https://doi.org/10.2519/jospt.2011.3503

  32. De Meulemeester, K., Calders, P., De Pauw, R., Grymonpon, I., Govaerts, A., & Cagnie, B. (2017). Morphological and physiological differences in the upper trapezius muscle in patients with work-related trapezius myalgia compared to healthy controls: A systematic review. Musculoskeletal science & practice, 29, 43–51. https://doi.org/10.1016/j.msksp.2017.02.007

  33. Lee, K. J., Han, H. Y., Cheon, S. H., Park, S. H., & Yong, M. S. (2015). The effect of forward head posture on muscle activity during neck protraction and retraction. Journal of physical therapy science, 27(3), 977–979. https://doi.org/10.1589/jpts.27.977

  34. Lee, S. T., Moon, J., Lee, S. H., Cho, K. H., Im, S. H., Kim, M., & Min, K. (2016). Changes in activation of serratus anterior, trapezius and latissimus dorsi with slouched posture. Annals of Rehabilitation Medicine, 40(2), 318–325. https://doi.org/10.5535/arm.2016.40.2.318

  35. Bordoni, B., & Varacallo, M. A. (2025). Neuroanatomy, cranial nerve 11 (Accessory). StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK507722/

  36. Ludewig, P. M., & Reynolds, J. F. (2009). The association of scapular kinematics and glenohumeral joint pathologies. Journal of Orthopaedic & Sports Physical Therapy, 39(2), 90–104. https://doi.org/10.2519/jospt.2009.2808

  37. Camargo, P. R., & Neumann, D. A. (2019). Kinesiologic considerations for targeting activation of scapulothoracic muscles - part 2: trapezius. Brazilian journal of physical therapy, 23(6), 467–475. https://doi.org/10.1016/j.bjpt.2019.01.011

  38. O’Driscoll, J., Minarro, J. C., & Sanchez-Sotelo, J. (2024). Paralysis of the trapezius muscle: Evaluation and surgical management. JSES Reviews, Reports, and Techniques, 4(3), 329–340. https://doi.org/10.1016/j.xrrt.2024.03.014

  39. Nyemb, P. M. M. A., Fontaine, C., & Ndoye, J.-M. (2017). Review of the literature on anatomical variations of the trapezius muscle. MOJ Anatomy & Physiology, 4(5), 385–390. https://doi.org/10.15406/mojap.2017.04.00152

  40. Fernández-de-Las-Peñas, C., Ge, H. Y., Arendt-Nielsen, L., Cuadrado, M. L., & Pareja, J. A. (2007). Referred pain from trapezius muscle trigger points shares similar characteristics with chronic tension type headache. European journal of pain (London, England), 11(4), 475–482. https://doi.org/10.1016/j.ejpain.2006.07.005

  41. Adigozali, H., Shadmehr, A., Ebrahimi, E., Rezasoltani, A., & Naderi, F. (2016). Ultrasonography for the assessment of the upper trapezius properties in healthy females: a reliability study. Muscles, ligaments and tendons journal, 6(1), 167–172. https://doi.org/10.11138/mltj/2016.6.1.167

  42. Kumbhare, D., Shaw, S., Ahmed, S., & Noseworthy, M. D. (2020). Quantitative ultrasound of trapezius muscle involvement in myofascial pain: comparison of clinical and healthy population using texture analysis. Journal of ultrasound, 23(1), 23–30. https://doi.org/10.1007/s40477-018-0330-5

Related Articles

Seated Thoracic Rotation with Breathing

Posted on December 22, 2025

The Seated with is a tehcnique used to increase the available active Rotation . The following s likely experience on the side contralateral (opposite) to the direction of rotation: Starting Position: Rotation is first performed to establish a baseline and the presence of any asymmetries. The exercise is then performed with the following sequence: This sequence can be repeated several times each di

Shoulder Girdle

Posted on December 19, 2025

The Shoulder Girdle is comprised of 3 joints and 2 functional articulations, with only one point of direct contact with the axial skeleton. It’s ball-and-socket construction facilitates maximum range of motion in all three planes of movement making it the most mobile joint in the body (SOURCE-7); however, this is at the expense of its stability. Muscles of the shoulder complex provide the dynamic

Deep Front Line

Posted on December 15, 2025

The Deep Front Line is one of several proposed by Thomas Myers (SOURCE-1). As its name suggests this line lies deep of the , and . While the extensive integration of deep tissues allows this line to operate in all three dimensions, only atic is a movement that is primarily and uniquely generated by this line (SOURCE-1). The Deep Front Line is predominantly associated with slower-twitch s, which su