Martingales- this is a piece of equipment that is used to prevent the horse from raising his head. A standing martingale is a single strand of leather or cord that attaches from the girth or chest plate to the cavesson, limiting the upward mobility of the head. A running martingale comes from the bottom of the girth or the chest plate as a single piece before splitting into two sections, each of which ends in a metal ring through which the reins run. When the rider tightens the reins, it places downward pressure on them, which, in turn, also puts downward pressure on the bit.

Metacarpus- this is a term that usually refers to the cannon bone of the forelegs, but technically this is the third metacarpus, as the second and fourth metacarpus are the inner and outer splint bones that are placed laterally next to the cannon bone.

Metatarsus- this is a term that usually refers to the cannon bone of the hind legs but technically this is the third metatarsus, as the second and fourth metatarsus are the inner and outer splint bones that are placed laterally next to the cannon bone.

Mitochondria- these are the small components of the cytoplasm that are principal sites of energy production from the oxidation of foodstuffs.

Morphological Factors- the various lengths, angles, circumferences, proportions and mass of the physical structure of the horse that are evaluated in regard to the suitability for expected functions.

Muscle Definition- implies how well-defined and visibly evident the muscles are in the horse’s anatomy. A horse with good muscle definition would have well-developed and protruding muscles that could easily be distinguished when observed. A horse with poor muscle definition would have flat, less voluminous muscles that permitted greater visibility of the underlying osseal structure.