An orthotist is a clinician involved with the assessment, fabrication, design, evaluation of orthoses, and, or in addition to, can assist in the formulation of orthoses. An orthosis(ses) is a device that is intended to mechanically compensate for a pathological condition. Obvious examples of orthosis would be a neck collar for someone who cannot support their head due to a muscle condition or weakness. Additionally, a powerchair is a form of orthotic for someone that cannot physically support their own weight, or walk. An orthotist prescribes or creates orthotics, which are devices applied to the exterior of the body to support and align the body and limbs, or to influence motion by assisting, blocking, or unloading part or all of an individuals body weight.