Â© 2000 John Wiley & Sons, Inc. An inverse relationship between household income and violence exposure in youth hasbeen reported in numerous studies (e.g., Garbarino & Crouter, 1978; Gelles, 1992; Gelles& Straus, 1979; Steinberg, Catalano, & Dooley, 1981).
The head, attached to the top of the vertebral column, is balanced, moved, and rotated by the neck muscles (). When these muscles act unilaterally, the head rotates. When they contract bilaterally, the head flexes or extends. The major muscle that laterally flexes and rotates the head is the sternocleidomastoid.
Watch lateral flexion here : Look straight ahead and then bring your chin down toward your chest. This is neck flexion, and the anterior scalene acts in it. The other muscles involved include the sternocleidomastoid (itâs in everything!), longus capitis, and longus colli.If you look straight ahead, then turn your head to the side, this is contralateral head rotation.atch lateral flexion here : Look straight ahead and then bring your chin down toward your chest. This is neck flexion, and the anterior scalene acts in it. The other muscles involved include the sternocleidomastoid (itâs in everything!), longus capitis, and longus colli.