Sternocleidomastoid Pain in hEDS: Causes and Symptoms

One muscle that often deserves attention is the sternocleidomastoid, usually shortened to SCM. It is easy to feel, easy to overwork, and deeply involved in head position, breathing mechanics, balance, and jaw-neck tension.

The SCM sits on the front and side of the neck and helps control head movement.

What the sternocleidomastoid does

The sternocleidomastoid is a paired muscle, meaning there is one on each side of the neck. Each SCM starts at two points near the front of the upper chest, the sternum and clavicle, then travels diagonally upward to attach behind the ear at the mastoid process of the skull. This diagonal path gives it several jobs:

• Turning the head to the opposite side

• Tilting the head toward the same side

• Helping bring the head forward

• Assisting with breathing when demand is high

• Supporting head and neck position during upright posture

  
  

A simple example helps. Turn your head to the left and place your fingers on the right front side of your neck. The firm band that stands out is likely the right SCM working.

In daily life, the SCM rarely acts alone. It works with deep neck flexors, upper trapezius, scalenes, jaw muscles, shoulder muscles, and the small stabilizers around the upper cervical spine. In a stable system, these muscles share the load. In hEDS, that load sharing can become uneven.

Why the SCM can matter in hEDS

Hypermobile Ehlers-Danlos syndrome affects connective tissue. Ligaments and joint capsules may provide less passive stability than expected. As a result, muscles often work harder to create active stability around joints.

The neck is a common place for this to show up. The head is heavy, the cervical spine is highly mobile, and the muscles around it must make constant small adjustments. When the deep stabilizers fatigue or do not coordinate well, larger muscles such as the SCM may step in. That compensation can be useful at first. Over time, it may contribute to:

• Neck pain and tightness

• Headaches, especially around the temples, forehead, or behind the eyes

• Jaw tension or a feeling of clenching

• Dizziness or a sense of poor head position

• Shoulder and upper chest tension

• Symptoms that flare after reading, driving, screen use, or looking down

  
  

The SCM can also contain trigger points, which may refer pain to the head, ear, eye area, jaw, or throat region. Trigger points are not the only explanation for these symptoms, but they can be one piece of the puzzle.

A neutral head position can reduce extra demand on the SCM and nearby neck muscles.

Common reasons the SCM becomes irritated or overworked

In hEDS, SCM discomfort is rarely caused by one thing. It is more often a mix of joint laxity, nervous system sensitivity, posture habits, and muscle endurance limits.

Deep neck flexor weakness

The deep neck flexors sit closer to the spine than the SCM. They help support the head in a subtle, controlled way. If they are weak or poorly coordinated, the SCM may dominate simple tasks like lifting the head, nodding, or holding posture.

A common clue is feeling the front neck muscles strain during exercises that are supposed to feel small and controlled.

Forward head posture and screen use

Looking down at a phone, laptop, book, or craft project can increase the workload on the neck. The SCM may stay mildly contracted for long periods. For someone with hEDS, even low-level effort can become irritating when it lasts too long.

Cervical instability or poor proprioception

Some people with hEDS have trouble sensing where their joints are in space. This is called reduced proprioception. The neck may respond with extra guarding. The SCM can become part of that guarding pattern.

If symptoms include fainting, drop attacks, severe neurological signs, new weakness, or worsening instability, medical assessment is needed.

Breathing patterns

The SCM can help lift the upper chest during heavy breathing. When stress, pain, asthma-like symptoms, dysautonomia, or poor rib mobility lead to upper chest breathing, the SCM may work as an accessory breathing muscle more often than it should.

Strain from sudden movement

Because hEDS can involve less joint restraint, quick head turns, awkward sleep positions, dental appointments, coughing, or minor whiplash-type events may irritate the SCM and surrounding tissues.

Management starts with calming the system

Strength matters, but irritated muscles often need reassurance before they need more challenge. A helpful plan usually combines pacing, gentle mobility, breathing, and progressive strength. Try these low-risk strategies first:

• Use heat for short periods if it reduces guarding.

• Support the arms during reading or phone use to reduce shoulder and neck load.

• Change positions often instead of trying to hold a “perfect” posture.

• Keep screens closer to eye level when possible.

• Practice slow nasal breathing with the lower ribs moving gently outward.

• Avoid aggressive stretching of the front of the neck, especially if instability is a concern.

  
  

A key goal is to help the SCM stop acting like an emergency stabilizer all day.

Small changes to screen height can reduce repeated strain on the front of the neck.

Exercises that may help strengthen and coordinate the SCM

With hEDS, exercise should feel controlled, not forceful. Start with very low effort. Mild muscle work is fine. Sharp pain, spreading symptoms, dizziness, visual changes, or a sense of instability are signals to stop and get guidance.

Chin nods for deep neck support

Lie on your back with knees bent. Imagine gently nodding “yes” without lifting the head. The movement is tiny. The throat and jaw should stay relaxed.

Hold for 3 to 5 seconds. Repeat 5 to 8 times.

This exercise trains the deeper stabilizers, so the SCM does not have to do every job.

Gentle isometric rotation

Sit tall with the head level. Place your right hand against the right side of your face near the cheekbone. Try to turn your head to the right while your hand prevents movement. Use only about 20 to 30 percent effort.

Hold for 3 to 5 seconds. Repeat 3 to 5 times each side.

This can build neck strength without large-range movement.

Gentle isometric side bend

Place your hand against the side of your head above the ear. Press your head lightly into your hand without letting the neck move.

Hold for 3 to 5 seconds. Repeat 3 to 5 times each side.

Keep shoulders relaxed and breathing steady.

Supported head lifts only if tolerated

This is more demanding and not right for everyone. Lie on your back and perform a tiny chin nod. Then barely lighten the weight of the head, as if floating it from the surface. Lower right away.

Repeat only a few times. If the SCM pops out strongly, cramps, or symptoms increase, return to easier work.

Scapular and upper back support

The neck often feels better when the shoulder girdle helps. Try gentle rows with a light resistance band, wall slides, or shoulder blade squeezes. Keep the effort low and smooth.

For many people, a stronger upper back reduces the feeling that the neck has to hold everything together.

Low-effort isometrics can build control without forcing large neck movements.

A supportive plan is gradual and flexible

Understanding the Sternocleidomastoid in hEDS Causes Symptoms and Strengthening Tips starts with seeing the SCM as part of a larger support system. It may be tight because it is weak. It may be painful because it is overprotective. It may be overworked because other stabilizers need help. The best approach is usually gentle and layered:

1. Calm irritated tissues.

2. Improve breathing and posture variety.

3. Train deep neck control.

4. Add low-effort isometrics.

5. Build shoulder and upper back endurance.

6. Progress slowly, with symptom response as the guide.

   
   

If neck symptoms feel complex, a physical therapist familiar with hEDS can help identify whether the SCM is the main driver, a compensation, or just one part of a broader pattern. Progress may be slow, but small gains in control and endurance can make daily activities feel safer and less exhausting.

Before starting any exercise regimen, it is important to discuss with YOUR health care team to ensure that it is right for your general health situation.