ABSTRACT
The head has two distinctive portions: The cranium is the portion of the skull that encloses the brain which is named neurocranium and consists of eight bones. In biomechanics, the neck's movement is described in connection with the vertebral column and the thorax. The vertebral column and the thorax with its sternum have a direct connection with the neck. The sternocleidomastoideus muscle is one of the most important muscle of the neck region. There are two groups of muscles, suprahyoid and subhyoid. From the group suprahyoid there are digastricus, a pair of muscles having two bellies separated by a tendon that extends from the anterior inferior margin of the mandible to the temporal bone which serve to open the jaw. Most of the muscles which act on the forearm also act on the wrist. Muscles involved in the movement of flexion and extension of the elbow can be described in many ways.
