Quadratus is Latin for square and quadratus muscle may refer to:

• Depressor labii inferioris muscle, also known as musculus quadratus labii inferioris
• Levator labii superioris muscle, also known as musculus quadratus labii superioris
• Pronator quadratus, a square shaped muscle on the distal forearm that acts to pronate (turn so the palm faces downwards) the hand
• Quadratus femoris muscle, a flat, quadrilateral skeletal muscle. Located on the posterior side of the hip joint
• Quadratus lumborum muscle, a muscle of the posterior abdominal wall
• Quadratus plantae muscle, a muscle in the foot

This disambiguation page lists articles associated with the title Quadratus muscle.
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