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.
Despite the curiosity that their condition has generated, the Hensel twins have managed to live private lives with relatively little press attention. At the age of 16, they gave an interview on The Learning Channel on December 17, 2006, in which they discussed aspects of their daily lives and plans for the future. They currently star in their own reality series on TLC.
The Hensel twins have a single body with separate heads and necks, a chest that is wider than normal, two arms and two legs. At birth, they had a rudimentary arm attached to a shoulder blade at the back. The arm was removed, leaving the shoulder blade.
Abigail's head tilts laterally outward about 5 degrees to the right, while Brittany's tilts laterally at about 15 degrees to the left, causing her to appear shorter even when seated. Brittany's leg is in fact nearly two inches shorter than Abigail's leg; and Brittany tends to stand and walk on tip-toe which has given her a significantly larger calf muscle than Abigail. The continued growth of Abigail's spine was surgically halted after Brittany prematurely stopped growing. At age 12, they underwent surgery at Gillette Children's Specialty Healthcare to correct scoliosis and to expand their chest cavity to prevent future difficulties with breathing.
Each of the twins manages one side of their conjoined body. The sense of touch of each is restricted to her body half; this shades off at the midsagittal plane such that there is a small amount of overlap at the midline. Stomach aches however are felt only by the twin on the opposite side. They are effective in cooperatively using their limbs when both hands or both legs are required. By coordinating their efforts, they are able to walk, run, swim, and ride a bicycle normallyâ€”all tasks that they learned at a normal speed. Together, they can type on a computer keyboard at a normal speed and drive a car. However, their disparate heights led to difficulty in balancing a Segway, as shown in their 2012 reality series.