Original Editor - Daphne Jackson
The trapezius is a broad, flat, superficial muscle extending from the cervical to thoracic region on the posterior aspect of the neck and trunk. The muscle is divided into three parts: descending (superior), ascending (inferior), and middle. The muscle contributes to scapulohumeral rhythm through attachments on the clavicle and scapula, and to head balance through muscular control of the cervical spine.
The muscle inserts on the lateral third of clavicle, acromion, and spine of scapula.
- Spinal root of accessory nerve (CN XI) (motor)
- Cervical nerves (C3 and C4) (pain and proprioception)
The superficial muscles of the back (trapezius, latissimus dorsi, rhomboids, levator scapula, serratus anterior) contribute to extension and side flexion of the axial skeleton. The cervical extensor muscles (descending trapezius and cervical erector spinae) counterbalance the pull of gravity on the head, as the head tends to be pulled into flexion due to its anterior centre of gravity
- Descending part: elevates pectoral girdle
- Middle part: retracts scapula
- Ascending part: depresses shoulders
- Descending and ascending together: rotates scapula upwards
- Bilateral contraction: extends neck
- Unilateral contraction:
The trapezius muscle is a postural and active movement muscle, used to tilt and turn the head and neck, shrug, steady the shoulders, and twist the arms. The trapezius elevates, depresses, rotates, and retracts the scapula, or shoulder blade.
Trigger Point Referral Pattern
superficial, can palpate upper, middle and lower
Upper is frequently involved in neck injuries
Hold the sloping superior lateral portion between fingers and thumb and palpate from
origin (O) toward the clavicle/acromion and its insertion (I)
With patient (pt.) standing: abduct shoulders to 90 degrees and retract shoulder girdle.
Slightly bend the trunk forward so antigravity.
Upper can also be seen with elevation and lower with depression 
Length tension testing
Patient: Positioned in supine lying with the arms resting by the side and the knees flexed.
Therapist: Standing at the head of the bed.
Action: The therapist supports the posterior aspect of the head with both hands and then passively flexes the craniovertebral joint. The right
hand stabilizes the lateral one third of the patient’s right clavicle and acromion palpating the muscle. The therapist then gently and slowly flexes, left side flexes and right rotates the mid and lower cervical spine with the left hand. The hand stabilizing and the hand moving the body part senses the tension in the muscle and barrier. The amount of range and the end feel is assessed and the reproduction of any symptoms is noted. This test is then repeated on the contralateral side and compared. 
Sit upright in a chair and make sure that your posture is correct. These stretches can be done in repetitions of 15-20 every hour to decrease trapezius muscle pain. Begin by rolling the shoulders back so that the shoulder blades feel like they are being pinched together. Then raise your shoulders up towards the ceiling and lower them down gently. You can then bend your neck from side to side by tilting your head towards your shoulder and counting to 3, then repeating in each direction.
Pain in the shoulder and neck can be prevented or reduced with massage.It is possible to reduce trapezius muscle pain through self-massage. Reach back with one hand and find your trapezius muscle. Beginning at the base of the neck, try to knead the trapezius muscles.
You can also apply some pressure to the area along your shoulders and between the shoulder blades. If there is an area that is more tender, apply pressure for ten seconds and then release so that the muscle can relax.
Recent Related Research (from Pubmed)
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- Moore KL, et al. Essential clinical anatomy. 4th ed. Baltimore, MD: Lippincott Williams and Wilkins, 2011.
- Department of Radiology, UW Medicine. Trapezius. www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas/upper-body/trapezius (accessed 27 January 2014).
- Kisner C, Colby LA. Therapeutic exercise: foundations and techniques. 6th ed. Philadelphia: F.A. Davis Company, 2012
- Neumann DA. Kinesiology of the musculoskletal system: foundations for rehabilitation. 2nd ed. St. Louis, MO: Mosby Elsevier, 2010.
- Physiotutors. Trapezius Strength Test. Available from: https://www.youtube.com/watch?v=9tfVeIhlY-o