Cobb angle below the fracture. The Cobb angle is the preferred method of measuring post-traumatic kyphosis in a recent meta-analysis of traumatic spine fracture classifications. Scoliosis cases with Cobb angles between 40 and 50 degrees at skeletal maturity progress at an average of 10 to 15 degrees during a normal lifetime. Cobb angles of more than 50 degrees at skeletal maturity progress at about 1 to 2 degrees per year. Those with Cobb angle of more than 60° usually have respiratory complications. Cobb angle The Cobb angle, named after the American orthopedic surgeon John Robert Cobb (1903–1967), was originally used to measure
Degrees of freedom (mechanics) rotation, which means that it has six degrees of freedom. The exact constraint mechanical design method manages the degrees of freedom to neither underconstrain nor overconstrain a device. The position of an "n"-dimensional rigid body is defined by the rigid transformation, ["T"] = ["A", "d"], where "d" is an "n"-dimensional translation and "A" is an "n" × "n" rotation matrix, which has "n" translational degrees of freedom and "n"("n" − 1)/2 rotational degrees of freedom. The number of rotational degrees of freedom comes from the dimension of the rotation group SO(n). A non-rigid or deformable body may be thought of