Dr. William Fitzgerald, the founder of Reflexology, he was a medical doctor and began to  treating organs through pressure points. In his book Zone Therapy, he makes some interesting remarks about it's history.

'A form of treatments by means of pressure points was known in Indian and China 5000 years ago.  This knowledge appears to have been lost or forgotten. Perhaps it was put aside in favour of acupuncture, which emerged as the stronger of that root.'

Reflexology based on the zone system, there are distinct relationship between the body's zones and the reflex zones on the feet.  There are ten fields of zones in the feet which corresponds to the ten zones of the body and their organs. Generally the reflex zone of an organ occupies the same vertical zone in the feet as it does in the body.

In context of the reflex zones of the feet, the word reflex has two meanings
1) As reflecting the entire organism (head, neck, and trunk) on a small screen (the feet), rather like a reflex camera.
2) Referring to characteristic sections of the feet, which have been shown empirically to have a direct energy relationship with the internal organs.