longissimus capitis
A longissimus muscle that lies medial to the longissimus cervicis, between it and the semispinalis capitis. It arises by tendons from the transverse processes of the upper four or five thoracic vertebrae, and the articular processes of the lower three or four cervical vertebrae, and is inserted into the posterior margin of the mastoid process, beneath the splenius capitis and sternocleidomastoid.[WP,unvetted].