Wikipedia notes:
Abigail Loraine Hensel and Brittany Lee Hensel (born March 7, 1990) are dicephalic parapagus twins, meaning that they are conjoined twins, each of whom has a separate head, but whose bodies are joined. They are highly symmetric, giving the appearance of having just a single body with little variation from normal proportion. In fact, several vital organs are doubled up; each twin has a separate heart, stomach, spine, and spinal cord.
Each twin controls her half of their body, operating one of the arms and one of the legs. This means that as infants, the initial learning of physical processes that required bodily coordination, such as clapping, crawling, and walking required the cooperation of both children. While each is able to eat and write separately and simultaneously, activities such as running and swimming must be coordinated and alternate symmetrically. Other activities as diverse as brushing hair and driving a car require that each twin perform a sequence of separate actions that coordinate with the other.
The following video was made when they were in high school:
A reminder of the human spirit and ability to triumph in the face of adversity. Food for thought, especially on a day that may have you down. END
PS: Anatomically:
