Semispinalis capitis
Semispinalis Capitis
The semispinalis capitis is a thick, long muscle deep in the back of the neck that tilts the head backward and holds it upright. It starts in the cervical and upper thoracic spine and attaches to the occipital bone. Because the greater occipital nerve, which supplies sensation to the back of the head, passes between these muscles, this muscle often comes up when explaining why a stiff, aching neck can be accompanied by aching at the back of the head.
Where is it, and what does it do?
The semispinalis capitis lies in the deep layers at the back of the neck. It belongs to the transversospinalis group, a group of small muscles running along the spine. As its name suggests, it is the semispinalis muscle that attaches to the head: “capitis” means “of the head.”
- Origin — Articular processes of the lower cervical vertebrae (C4–C7) and transverse processes of the upper thoracic vertebrae (T1–T6)
- Insertion — The occipital bone, between the superior and inferior nuchal lines
It is relatively thick and long compared with other muscles at the back of the neck. If you feel just to either side of the midline at the back of your neck, the firm, column-like structure you feel is usually this muscle. The trapezius and splenius capitis and splenius cervicis cover it, while the suboccipital muscles and multifidus lie deeper beneath it.
Here is what it does.
- When both sides work together — It tilts the head and neck backward.
- When only one side works — It tilts the head to the same side and rotates it to the opposite side.
- Throughout the day — It works as a postural muscle to keep the head upright.
The human head is fairly heavy, so when it moves forward, this muscle has to keep holding it from behind to stop it from dropping forward. This is also why the back of your neck can feel stiff and achy after spending a long time in a forward head posture.
How it can feel in everyday life
After looking down at a smartphone or laptop for a long time, you may feel a firm pulling sensation just to the side of the midline at the back of your neck, with an ache extending up to the base of your skull. The greater occipital nerve, which supplies sensation to the back of the head, passes through this area. Because this nerve travels between the muscles, stiffness at the back of the neck can sometimes feel as though the ache is spreading toward the back of the head.
One explanation is that signals from the trigeminal nerve, which supplies sensation to the face and jaw, and the upper cervical nerves converge in the same region of the brainstem. This means that tension at the back of the neck can be accompanied by an aching sensation in the head, and muscles at the back of the neck come up in discussions of tension-type headache and occipital neuralgia.
Try these ways to manage it
- Adjust your screen to eye level. Having the top of the monitor at eye level helps keep your head from moving as far forward. See Monitor height and viewing distance.
- Try chin tucks. While standing, gently draw your chin backward as though making a double chin, hold for 5 seconds, and release. This can feel as though the deep muscles at the back of your neck are getting a rest.
- Stretch by lowering your head. While seated, slowly lower your head and lightly place your hands on the back of your head, letting only their weight provide the pull. A comfortable stretch along the middle of the back of your neck is enough.
- Apply warmth. Placing a warm towel on the back of your neck can help tight muscles feel more comfortable.
- Make time for breaks. Once every 30–40 minutes, lift your head, look into the distance, and roll your shoulders.
When to take a closer look
A stiff, aching neck is common, but unusual signs need separate attention—for example, a sudden severe headache that feels different from your usual headaches, numbness or tingling and weakness in your arms and hands, or a stiff neck accompanied by a fever.