Sentence:  Her pin bones, <WSD>thurls</WSD>, and hips should be wide apart and level. The pin bones are the points at the rear of the cow protruding out from the pelvis. The <WSD>thurls</WSD> are the hip joints where the rear legs attach on either side of the cows pelvis. Webster 1913 
Meaning of the word marked with <WSD> tags:  Either of the rear hip joints where the hip connects to the upper leg in certain animals, particularly cattle; often used as a reference point for measurement.