[TA] muscle of suboccipital triangle; origin, spinous process of axis; insertion, middle of inferior nuchal line of occipital bone; action, rotates and draws head backward; nerve supply, dorsal branch of first cervical (suboccipital).suboccipital muscles. SYN: musculus rectus capitis posterior major [TA], greater posterior rectus muscle of head, musculus rectus capitis posticus major.