Muscle · Head

Rectus capitis posterior major

Musculus rectus capitis posterior major

Rectus capitis posterior major is the largest of the four small suboccipital muscles buried at the very base of the skull, beneath the trapezius and semispinalis. It runs from the spinous process of the axis — the second neck vertebra — upward and outward to the skull. It extends the head on the neck, and it turns the face toward the same side by rotating the atlas on the axis. Its real job, though, is not power but precision: like the rest of the suboccipital group it is extraordinarily rich in muscle spindles and works as the fine-tuning and position-sense system for the head. That is why this small, deep area features so heavily in the forward-head and tension-headache picture.