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
P-90 rather than subtract the signal between the coils; thus, the impedance can be lower, avoiding overwinding to obtain sufficient output. There is less signal cancellation. Sonically these sit somewhere between a true P-90 and a stacked pickup. They don't chime but they aren't nasal or lifeless either. They are ideal candidates for overdriven sounds where loss of sparkle is less important than avoiding hum amplification. These type of pickups have the same appearance of P-90s. The new generation Zero-Hum P-90 Hx by Kinman strives to have a P-90 sound and appearance, but is far more complex, with 202 individual parts.