This document discusses spinal orthosis and cervical orthosis. It provides an overview of the principles and indications for orthotic devices. Specifically, it outlines the functions of orthosis in relieving pain, immobilizing joints, reducing weight bearing, preventing and correcting deformities, and improving function. It also describes different types of cervical orthosis including soft collars, Philadelphia collars, and halo vests. The key objectives of spinal orthosis are to control spinal position, apply corrective forces, and aid stability.