Patrick's test or FABER test (for Flexion, ABduction, and External Rotation) is performed to evaluate pathology of the hip joint or the sacroiliac joint.
The test is performed by having the tested leg flexed, abducted, and externally rotated. If pain is elicited on the ipsilateral side anteriorly, it is suggestive of a hip joint disorder on the same side. If pain is elicited on the contralateral side posteriorly around the sacroiliac joint, it is suggestive of pain mediated by dysfunction in that joint.
^White, [edited by] Fred Ashley (2009). Physical signs in medicine and surgery : an atlas of rare, lost and forgotten physical signs : includes a collection of extraordinary papers in medicine, surgery and the scientific method. [Ocala, FL]: Museum Press. p. 177. ISBN978-1441508287.