When the constriction cuts off the blood supply to the fingers, the fingers can form a peak with the most palmar digit being the index finger. Normal neurovascular bundles are not present in the distal parts. Hands with fused fingers need to be released in phases to preserve the distal blood supply. Paterson IVOne of the most severe consequence of constriction strains is probably intrauterine amputations, this is where the constriction goes as deep as the bone and cuts off the blood supply of the proximal extremity. The result will be that the developing toe or finger will become ischemic and fall off. Because the result is a transverse amputation that cuts off the vascular supply to the developing extremity, the actual constriction ring is not seen. This can result in different outcomes:

complete resorption; this is the most common form of amputation. In this form the amputated digit is completely resorbed during intrauterine development and therefore the amputated digit cant be found. recovery of the digit; the digit is recovered with the placenta during delivery. engraftment elsewhere; the amputated digit can be, in rare cases, engrafted somewhere on the fetus.Intrauterine deathIn extremely rare cases a strain can form around the umbilical cord and cut off the blood supply to the fetus which will result in intrauterine death.
Because of these other anomalies the names "Constriction Ring Syndrome", "Constriction Band Syndrome", and "Streeter Bands" are given to this defect/disease. This is sometimes attributed to vascular disruption shared between cleft palate and other forms of cleft defects occurring together with ABS; this co-occurrence suggests an "intrinsic" defect of the blood circulation.The second theory postulates the involvement of an intrauterine disruption during pregnancy followed by a cascade of events involving amniotic rupture. When spontaneous rupture of the amnion occurs early in the second trimester, the separation of amnion from chorion produces many small, thin strands that can become entangled within digits and toes. Later, as the fetus grows but the bands do not, the bands become constricting. This constriction reduces blood circulation, hence causes congenital abnormalities. In some cases a complete "natural" amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth. The names "Amniotic Band Syndrome" (ABS), "Amniotic Disruption Complex", and "Amniochorionic Mesoblastic Fibrous Strings" are based on this theory. The third theory postulates the involvement of intrauterine trauma. Intrauterine trauma could be something like amniocentesis, or something like a fetal surgery. An intrauterine trauma could result in hemorrhage leading to acrosyndactyly. One study also showed the presence of bands as confirmed by sonography after fetal surgery.Because of these different theories, there are many names for this syndrome. For a long time people believed the second theory about the amniotic rupture and strands.