Trapezius - Muscle Physiology & Functional Anatomy





  • Upper Fibers

    • Medial third of the superior nuchal line and external occipital protuberance of the skull


  • Middle Fibers

    • Spinous processes of vertebrae T1-T3 & C7


  • Lower Fibers

    • Spinous processes of vertebrae T4-T12


  • Upper Fibers

    • Lateral third of the posterior clavicle


  • Middle Fibers

    • Medial border of acromium process


  • Lower Fibers

    • Inferior middle spine of scapula

Major Artery:

  • Transverse cervical artery


Neural Innervation:

  • Accessory Nerve (motor function)

  • Cervical spinal nerves C3 & C4 (motor & sensory)


Trigger Points:

Trigger Points of the TrapTrapezius Trigger Points




Concentric Functions:

  • Upper Fibers

    • Elevation of the scapula

    • Extension of the cervical spine

    • Extension, lateral flexion & rotation of the atlantoccipital & antlantoaxial neck


  • Middle Fibers

    • Adduction (rectaction), upward rotation and elevation of the scapula


  • Lower Fibers

    • Upward rotation, adduction (retraction) & depression of the scapula

    • Weak extensor of the thoracic spine


Eccentric Functions:

  • Upper Fibers

    • Decelerates cervical flexion, lateral flexion & rotation

  • Middle Fibers

    • Decelerates scapular abduction (protraction) & upward rotation


  • Lower Fibers

    • Decelerates scapular elevation



Isometric Function:

  • Upper Fibers

    • Assists in providing dynamic stability to the cervical spine and shoulder complex


  • Middle Fibers

    • Assists in dynamically stabilizing the scapula during functional movements


  • Lower Fibers

    • Assists in dynamically stabilizing the scapula



Related Muscles






More Images of the Trapezius Muscle



More Information about the Trapezius Muscle

The trapezius muscle is named because of its trapezoidal shape.


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