CRLF test (cervical rotation lateral flexion test) is used to evaluate the function of the superior thoracic aperture. With the cervical spine in a neutral position, the head is first turned maximally away from the side to be examined (A). In this position, the cervical spine is flexed, the ear toward the chest (B). The normal range of motion is about 70 degrees. If this movement is restricted, the test is considered positive and indicates a malfunction of the upper aperture. Both sides are compared.