The knee.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008124:Locomotion; D008297:Male; D008875:Middle Aged; D009068:Movement; D012399:Rotation; D012737:Sex Factors