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.
Splenius Capitus. The splenius capitus is a thick muscle that resembles a strap. It is located in the back of your neck. It begins at the base of your skull and ends at the top of your thoracic spine. This muscle allows for head extension, as well as lateral flexion and rotation of the cervical spine.ight muscles get worked during neck extensions. Photo Credit Jupiterimages/Goodshoot/Getty Images. Neck extensions are performed for a variety of reasons, including physical therapy after a neck or upper body injury, to relieve arthritis or joint pain, and as a strength building exercise.