This is not a prospective randomized clinical trial or a consecutive case series, but rather the description of a technique developed years ago, but still applicable. As spine surgeons, we wish to know the true correctability of a curvature before determining the best method of treatment. Do we need to do a posterior surgery only? Do we need to do a combined anterior and posterior surgery? Do we need to place the patient in preoperative skeletal traction? Although many different techniques have been described for the determination of true curve flexibility, the Moe Maximal Correction Test has never before been described.