0:00:00.000,0:00:02.990 (English captions by Jade Cheng from the Universtiy of Michigan) 0:00:02.990,0:00:07.109 Ulnar collateral ligament testing of the thumb[br]is performed to evaluate for instability found 0:00:07.109,0:00:09.460 on a gamekeeper's or skier's thumb. 0:00:09.460,0:00:14.400 After stabilizing the first metacarpal, a[br]valgus stress is applied to the thumb at the 0:00:14.400,0:00:16.329 metacarpophalangeal joint. 0:00:16.329,0:00:19.830 Laxity indicates a partial or complete ulnar[br]collateral ligament tear.