Sirenomelia

Sirenomelia, also known as Mermaid Syndrome, is a very rare disorder in which the legs are stuck together, making them look like a mermaid's tail. This, however, is as rare as conjoined twins, and only happens to one out of every 100,000 live births.^[1] It is usually very bad for the kidney and bladder, and only about four survivors were known to be alive as of July 2003.^[2]

Sirenomelia Media

Classification of sirenomelia by the presence or absence of bones within the lower limb.*I) all bones of thigh and lower leg present*II) fused fibula*III) fibula absent*IV) partially fused femur, fused fibula*V) partially fused femur*VI) fused femur, fused tibia*VII) fused femur, tibia absent

References

↑ Kallen B, Castilla EE, Lancaster PA, Mutchinick O, Knudsen LB, Martinez-Frias ML, Mastroiacovo P, Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation. J Med Genet 29 (1) (1992). p. 30–5. doi:10.1136/jmg.29.1.30.
↑ Journal of Pediatric Surgery: A surviving infant with sirenomelia (mermaid syndrome) associated with absent bladder. ScienceDirect (25 July 2003). Retrieved 2008-02-16.

[Kallen-1] Kallen B, Castilla EE, Lancaster PA, Mutchinick O, Knudsen LB, Martinez-Frias ML, Mastroiacovo P, Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation. J Med Genet 29 (1) (1992). p. 30–5. doi:10.1136/jmg.29.1.30.

[2] Journal of Pediatric Surgery: A surviving infant with sirenomelia (mermaid syndrome) associated with absent bladder. ScienceDirect (25 July 2003). Retrieved 2008-02-16.

[1]

[2]