Trapezius

The trapezius muscle is the large, flat muscle that covers the back of your neck, the tops of your shoulders and the upper half of your back. When someone who works at a desk says their shoulders feel tight, the spot they squeeze is usually the upper part of the trapezius.

Where is the trapezius muscle?

Seen from behind, the left and right trapezius together make a diamond shape. The muscle runs from the bump at the back of the skull down to the lower vertebrae of the upper back, and out sideways to the bony ridge on each shoulder blade (Ourieff et al., 2023).

Anatomists divide it into three parts, because the fibres run in different directions (Kenhub):

• Upper fibres start at the skull and the ligament along the back of the neck, and attach to the outer third of the collarbone.
• Middle fibres start at the top of the thoracic spine and attach to the tip of the shoulder and the ridge of the shoulder blade.
• Lower fibres start further down the thoracic spine and attach near the inner end of that ridge.

Unusually, movement is controlled by the accessory nerve, one of the nerves that leave the skull directly, while sensation travels through the third and fourth nerves of the cervical spine (Ourieff et al., 2023).

What does the trapezius do?

Its main job is to steady and move the shoulder blade, so your arm has a stable base. The upper fibres lift the shoulder blade, rotate it upwards and help extend the neck. The middle fibres draw it towards the spine. The lower fibres pull it down and help the upper fibres with the rotation (Ourieff et al., 2023). These movements work against the levator scapulae and the rhomboids, which turn the shoulder blade the other way.

On one side, the upper fibres also tilt the head towards that shoulder and turn the face to the opposite side (Kenhub).

Why does the upper trapezius get sore at a desk?

Pain from the upper part of the trapezius has long been linked with monotonous work such as computer work. When this muscle pain becomes long-term, the clinical name is trapezius myalgia (Andersen et al., 2008). Small studies help explain why it is such a common complaint:

• It stiffens over a long sitting session. When 25 healthy women sat at a computer for 90 minutes, ultrasound measurements showed the stiffness of the upper trapezius rising steadily over that time (Nitta et al., 2025).
• It doesn’t always switch off. In a study of 85 female office workers, those with neck pain had an upper trapezius that kept working after typing tasks had ended. The authors could not tell whether this was a cause or a result of the pain (Johnston et al., 2008). Women with diagnosed trapezius myalgia also showed more activity in the muscle while they were meant to be resting (Sjörs et al., 2009).
• Stress shows up in it. In 62 women, mental tasks such as timed arithmetic raised the electrical activity of the trapezius, even with no physical load at all (Lundberg et al., 1994).

None of this says the muscle is damaged. It describes a muscle asked to work lightly for hours, and one that rest, movement and stress all affect.

Are trapezius “knots” real?

The tender lumps people feel are usually called trigger points, described as hard nodules inside a taut band of muscle (Bordoni et al., 2025). The idea is disputed. One critical review argued that trigger point theory has no sound scientific basis, while accepting that the pain and tenderness people feel are real (Quintner et al., 2015).

Which conditions involve the trapezius?

The upper trapezius is part of the picture in neck pain from desk work, shoulder pain from computer work and a stiff neck after sleeping. A tight upper trapezius is also one corner of upper crossed syndrome (Russin et al., 2026), a popular model of desk posture with limited evidence behind it.

What does the research say helps?

The strongest trials point to strengthening rather than rest. In 48 women with trapezius myalgia from computer-heavy workplaces, ten weeks of specific strength training for the painful muscle reduced their worst pain by 35 points on a 100-point scale. General fitness training on an exercise bike gave only a small, short-lived drop (Andersen et al., 2008). In a larger trial of 198 working adults, two minutes a day on workdays reduced neck and shoulder pain compared with health information alone (Andersen et al., 2011). There is more on that trial in Is two minutes of exercise enough?.

Breaking up the long, light holding described above is what microbreaks are for.

When should you see a doctor about trapezius pain?

See a GP if neck pain or stiffness hasn’t gone after a few weeks, if painkillers haven’t helped, or if you have pins and needles or a cold arm (NHS). Ask for an urgent appointment or contact NHS 111 for sudden or very bad shoulder pain, pain after a fall or injury, or if you feel feverish and unwell (NHS). Call 999 if you have chest pain that spreads to your arms, neck or jaw (NHS).

Stretches for the upper trapezius are part of Bavelu’s neck and shoulder sessions, designed and filmed by physiotherapists.