The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.

DEFINITION:

limb

1. One of the paired appendages of the body used in locomotion or grasping. In humans, an arm or leg (upper limb or lower limb) with all its component parts (e.g., arm, forearm, and hand). In embryology, the skeleton of each limb is divided into four main parts: the zonoskeleton , comprising the scapula and clavicle (as a unit) and the hip bone; the stylopodium , comprising the humerus and femur; the zygopodium , comprising the radius and ulna and the tibia and fibula; and the autopodium comprising the hand and the foot.

2. A structure or part resembling an arm or leg.

anterior limb - A limb-like structure situated in front of or in the forward part of a structure.

ascending limb - A limb-like structure which is moving or growing upward.

descending limb - A limb-like structure which is moving or growing downward.

posterior limb - A limb-like structure situated in back of or in the back part of a structure.