it is a little freaky, but also amazing...
Brittany is the left twin, and Abigail is the right twin. They have two spines which join at the pelvis. They have two stomachs, three lungs, and at birth, three arms (the arm between their heads was underdeveloped and useless, and was amputated in infancy). In some way not yet understood, even though each controls only one arm and one leg, they are able to run, ride a bike, drive a car, type and do anything else anyone else can do