Constriction ring syndrome (CRS) is a congenital disorder with unknown cause. Because of the unknown cause there are many different, and sometimes incorrect, names. It is a malformation due to intrauterine bands or rings that give deep grooves in, most commonly, distal extremities like fingers and toes. In rare cases the constriction ring can form around other parts of the fetus and cause amputation or even intrauterine death. The anatomy proximal to the site of constriction (or amputation) is developmentally normal.[2][3][4]
CRS can be associated with other malformations, with club foot being most common.[5][6][7]
The precise configuration of the bands, lymphedema, and character of the amputations are not predictable and vary with each individual patient. Also, more than one extremity is usually affected, and it is rare for only one ring to present as an isolated malformation with no other manifestation of this syndrome.[2][3][8][9]
^Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN978-1-4160-2999-1.
^ abOgino T, Saitou Y (1987). "Congenital constriction band syndrome and transverse deficiency". J Hand Surg Br Vol. 12 (3): 343–348. doi:10.1016/0266-7681(87)90185-9. PMID3437201.
^Weinzweig N, Barr A (1994). "Radial, ulnar and median nerve palsies caused by a congenital constriction band of the arm: single stage correction". Plast Reconstr Surg. 94 (6): 872–876. doi:10.1097/00006534-199411000-00022. PMID7972438.