[Description] Twins are united from the waist to the lower breastbone, probably accounting for about 34% of conjoined cases. [Scientific Term] 
Omphalopagus
C r a n i o p a g u s
T h o r a o p a g u s
P y g o p a g u s
I s c h i o p a g u s
O m p h a l o p a g u s
D i c e p h a l u s