Relation Between Cervicogenic Headache and Forward Head Posture

"Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena.~Flexion rotation (FRT) test:~FRT is a manual examination technique with high sensitivity and specificity. It is performed with the patient in supine by passively taking the cervical spine into full flexion. End-range cervical flexion imparts ligamentous tension that impedes movement at vertebral segments below C2.7 Maintaining the flexion position, the patient's head is then rotated to each side until the patient reports pain or the operator determines that end of motion has been achieved. It is then determined if a restriction in ROM is present."