Personalized T-Rx Youth Long Sleeve T-Shirt. A cute green T-Rex dinosaur wearing a lab coat and stethoscope handing out prescriptions. Otherwise known as a T-Rx. Adorable gift for any medical professional who loves dinosaurs. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)