Withers
Look up  withers in Wiktionary, the free dictionary.
Withers are the ridge between the shoulder blades of an animal, typically a quadruped. In many species, this ridge is the tallest point of the body. In horses and dogs, it is the standard place to measure the animal's height. In contrast, cattle are often measured to the top of the hips.
The term (pronounced /ˈwɪð.ərz/) derives from Old English wither ("against'), because the withers are the part of a draft animal that pushes against a load.