Although having no specific standard, the Thoroughbred corresponds to a fine and precise description of the desired phenotype. It is a slender, harmonious, and athletic horse with an average height of 5.4 ft (1.65 m) at the withers. The general impression of slenderness is conveyed by a light and well chiselled head with a slightly convex rectilinear profile, large lively eyes, long and thin ears and neck, a well-protruding withers, a high and deep chest, and long legs. The musculature is well marked and the feet are relatively small. The best racehorses are of medium height, tall horses with weaker legs and feet being more prone to lameness and short ones disadvantaged by their shorter strides.