A muscle that arises from the lower half of the ligamentum nuchæ, from the spinous process of the seventh cervical vertebra, and from the spinous processes of the upper three or four thoracic vertebræ and inserts the mastoid process of the temporal bone, and into the rough surface on the occipital bone just below the lateral third of the superior nuchal line[WP,modified]. [ http://en.wikipedia.org/wiki/Splenius_capitis_muscle ]