Trapezius Muscle Test

Trapezius is a large trapezoid-shaped muscle on the posterior aspect of neck and trunk. The Trapezius Muscle Test is used to evaluate its strength and function.

See Also: Rotator Cuff of the Shoulder

How do you test the trapezius muscle?

The patient is seated and is asked to place the hands together over the head and to maintain the posture. The examiner stands behind the patient and pushes the elbows forward. Look for the contraction of the three parts of the trapezius.

Different part of the trapezius muscle can be tested separately as following:

To test the upper trapezius: elevate the shoulder with the arm slightly abducted or simultaneously resist shoulder abduction and head side flexion. If the shoulder is elevated with the arm by the side, levator scapulae and rhomboids are more likely to be involved.

Middle trapezius can be tested with the patient in a prone position with the arm abducted to 90° and externally rotated. Then resistance is applied to horizontal extension of the arm, while watching for retraction of the scapula and feeling for the contractions. If scapular protraction occurs, the middle fibres of trapezius are weak.

To test the lower trapezius, the patient again in prone lying position with arm abducted to 120° and the shoulder externally rotated. The examiner applies resistance to diagonal extension and watches for scapular retraction and feels for the contraction of the muscle fibres. If scapular protraction occurs, the lower trapezius is weak.

Trapezius Muscle Anatomy

Origin:

The trapezius muscle originates from:

1. the medial third of the superior nuchal line,
2. the external occipital protuberance,
3. the ligamentum nuchae,
4. the apices of the seventh cervical vertebra,
5. all the thoracic spinous processes,
6. the supraspinous ligaments of the cervical and thoracic vertebrae.

Insertion:

The Trapezius Muscle insertion is as following:

1. The upper fibers descend to attach to the lateral third of the posterior border of the clavicle.
2. The middle fibers of the trapezius run horizontally to the medial acromial margin and superior lip of the spine of the scapula.
3. The inferior fibers ascend to attach to an aponeurosis gliding over a smooth triangular surface at the medial end of the spine of the scapula to a tubercle at the scapular lateral apex.

Innervation:

It has been suggested that the upper fibers of this muscle have a different motor supply than that to the middle and lower portions. Recent clinical and anatomical evidence seems to suggest that the spinal accessory nerve provides the most important and consistent motor supply to all portions of the trapezius muscle, and although the C2–4 branches of the cervical plexus are present, no particular elements of innervation within the trapezius have been determined.

Function:

One of the functions of the trapezius is to produce shoulder girdle elevation on a fixed cervical spine. For the trapezius to perform its actions, the cervical spine must first be stabilized by the anterior neck flexors to prevent simultaneous occipital extension from occurring. Failure to prevent this occipital extension would allow the head to translate anteriorly, resulting in a decrease in the length, and therefore the efficiency, of the trapezius and an increase in the cervical lordosis.

References

1. Kendall HO, Kendall FP. Muscles-testing and function. Baltimore: Williams & Wilkins; 1999.
2. Mercer S, Campbell AH: Motor innervation of the trapezius. J Man Manip Ther 8:18–20, 2000.
3. Haymaker W, Woodhall B: Peripheral Nerve Injuries. Principles of Diagnosis. London: WB Saunders, 1953.
4. Ourieff J, Scheckel B, Agarwal A. Anatomy, Back, Trapezius. [Updated 2021 Jul 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK518994/
5. Sarvdeep S. Dhatt, Sharad Prabhakar – Handbook of Clinical Examination in Orthopedics. An Illustrated Guide-Springer Singapore.