Ankle stiffness is a common complication after ankle fracture, reconstructive surgery or total ankle replacement, and the usual limitation is in dorsiflexion. There are few articles in the literature concerning this frequent problem, and furthermore they are not recent and tend to be controversial. The purpose of this anatomical study was to evaluate and quantify the effect of ankle collateral ligament release on dorsiflexion, specifically the amount of increase in ankle dorsiflexion following section of the two ligaments most often implicated in ankle stiffness: the deep posterior tibiotalar ligament (dPTTaL, or posterior deep deltoid) and the posterior talofibular ligament (PTaFL).