Deep neck flexors

The deep neck flexors are a small group of muscles lying directly on the front of the neck vertebrae, behind the throat. The main two are the longus colli and the longus capitis, and they are often called the deep cervical flexors (Jull et al., 2008). “Deep” separates them from the larger muscles nearer the surface at the front of the neck, such as the sternocleidomastoid.

Where are the deep neck flexors and what do they do?

The longus colli runs the whole length of the neck, from the front of the atlas, the first neck vertebra, down to the third thoracic vertebra. It sits behind the gullet, windpipe and thyroid gland, is supplied by nerves from C2 to C6, and is grouped with the longus capitis, the rectus capitis anterior and the anterior scalene as the muscles in front of the spine. When both sides contract, it bends the neck forward, and this also helps stabilise the spine, aligning the head and neck for upright posture (Kenhub).

Physiotherapists focus on one movement in particular, a small nod of the head on the neck called craniocervical flexion. Research pointing to these muscles’ role in supporting the neck’s natural curve, the cervical lordosis, and the individual segments of the cervical spine is what led to a standard clinical test of that nod (Jull et al., 2008).

What happens to the deep neck flexors in neck pain?

In a small laboratory study, researchers recorded the deep flexors directly with electrodes placed through the nose onto the back of the throat. During the harder stages of the nodding test, the 10 people with chronic neck pain used their deep flexors less than the 10 without pain (Falla et al., 2004).

Summarising this research, the test’s developers describe a pattern in people with neck pain: less activity in the deep flexors, more in the superficial ones, and less endurance. This appears to be common to neck pain of many different causes (Jull et al., 2008), and the studies can’t show whether it comes before the pain or because of it.

Are the deep neck flexors linked to desk posture?

There is some trial evidence:

• Drift at the screen. During a 10-minute computer task, 58 people with chronic neck pain drifted further into a forward head posture than 10 people without pain. Those randomly assigned to six weeks of training the craniocervical flexors drifted less afterwards (Falla et al., 2007).
• What training changes. A review of 12 trials found strong evidence that training these muscles improves coordination of the neck muscles, and that it improved head and neck posture, but it had little or no effect on strength and endurance at higher loads. The authors suggest combining it with other training (Blomgren et al., 2018).
• Headaches. In 200 people with headaches arising from the neck, a low-load exercise programme, manipulative therapy, or both reduced headache frequency and intensity, with effects still present at 12 months (Jull et al., 2002).

For office workers with chronic neck pain more broadly, a review found low-certainty evidence that strengthening the neck, shoulder and shoulder-blade muscles reduces pain and disability (Jones et al., 2024). The forward head posture exercises page shows one exercise from the app, and forward head posture covers the wider picture. The nodding exercise used in these trials is best learned with a physiotherapist, who can check that the deep muscles are doing the work.

When to see a doctor

See a GP if neck pain or stiffness hasn’t gone after a few weeks, painkillers haven’t helped, or you have pins and needles or a cold arm (NHS). Calcium deposits in the longus colli tendon can cause neck pain with painful swallowing, reduced movement and fever (Kenhub), which needs a doctor. Call 999 or go to A&E for a headache with a very high temperature, a stiff neck or sensitivity to bright light, or one that starts suddenly and is extremely painful (NHS). For headaches that seem to start in the neck, see Can neck pain cause headaches?