There are nearly a dozen different types of conjoined twins. One of the most common classifications is thoracopagus twins. These twins are connected at the upper portion of the torso.
Source: Conjoined Twins Facts | University of Maryland Medical Center http://umm.edu/programs/conjoined-twins/facts-about-the-twins#ixzz3IrRhXfKT
University of Maryland Medical Center
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