Trapezius - Muscle Physiology & Functional Anatomy

Anatomy

Origin:

• 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
    

Insertion:

• 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:

Physiology

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

• Levator Scapula (upper fibers)

• Rhomboids (lower & middle fibers)

Antagonists

• Serratus Anterior

• Latissimus Dorsi

Exercises:

• Traps Exercises

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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