Very short people are called dwarfs. In some dwarfs the torso is as big as a regular person's but arms and legs are short. The term midgets has been used to refer to dwarfs who are normally proportioned, but many short people do not like that word any more. The reasons people become dwarfs or midgets is that either the cartilage (the part that makes your bones grow) is sick (you become a dwarf), or the hormones (a chemical that normally makes everything in your body grow) is too little (you become a midget).''
The shortest man was Gul Mohammed until his death in October of 1997. On July 19, 1990 he was 22 1/2 inches tall and weighed 37 1/2 pounds. Here is a picture of him on the Contact Press Images website.
There is an association for people of short stature called Little People of America. It helps little people to meet each other and to deal with the many problems of being very short. They have a very good website.