Amniotic constriction ring Digital constriction ring 2009-09-16T11:08:16Z HP:0010491 UMLS:C4021261 The description should specify the hand and digit that is affected and the approximate location of the band relative to the phalanges. It may be described as partial, if it does not involve the entire circumference of the digit. Amniotic constriction rings of digits A narrow segment of significantly reduced circumference of a digit.