An implantable, threaded rod that is a component of a cervical spine immobilization system (commonly known as a Halo vest) designed to secure the head ring to the skull of the patient by penetrating the outer bone of the skull at brow level. Commonly referred to as a pin, it is typically made of metal (e.g., stainless steel), may be ceramic-tipped, or made of non-ferromagnetic materials. It is a single-patient device that may be reapplied to the patient over a short term (single-use) before being discarded.