This muscle's primary function is elbow flexion and forearm supination. The cast is applied with the distal fragment in palmar flexion and ulnar deviation. It also has a synergistic role in extension and lateral flexion of the lumbar spine. Facet joints appear to have little influence on the range of side bending (lateral flexion). Neck stiffness is the result of inflamed meninges stretching due to flexion of the spine. Both heads of the biceps femoris perform knee flexion. Both flexion and extension increase compression in the carpal tunnel. They allow significant "flexion", "extension" and moderate lateral flexion (side-bending). These two muscles are the strongest pronators and aid in plantar flexion. Cited advantages include maintenance of finger extension and prevention of new flexion contractures. Psoas can be palpated with active flexion of the hip. Reduced knee flexion may be experienced during activities. That is, there is a fixed plantar flexion of the foot. The brachialis is the prime mover of elbow flexion. Single plane resistance exercises against cervical flexion, extension, bending, and rotation are used.