What Is The Mastoid Process? mastoid process. n. A conical protuberance of the posterior portion of the temporal bone that is situated behind the ear and serves as a site of muscle attachment. mastoid bone. The part of the first pharyngeal arch in the embryo, developing into the upper jaw in the embryo. What bone
What Action Does The Sternocleidomastoid Perform? When acting together it flexes the neck and extends the head. When acting alone it rotates to the opposite side (contralaterally) and slightly (laterally) flexes to the same side. It also acts as an accessory muscle of inspiration. What does Sternocleidomastoid attach to? Origin Insertion Superior border/anterior surface of