A cranial prosthesis is a wig for medical patients who have permanent hair loss (such as alopecia areata, alopecia totalis, trichotillomania), or temporary hair loss resulting from treatment for chemotherapy, radiation, or any other clinical disease. The term, cranial prosthesis, is used when applying for medical insurance or tax deduction status. Other common terms for a wig used for medical purposes include: full cranial prosthesis, hair prosthesis, cranial hair prosthesis, extra-cranial prosthesis.Understand that Since the above processes are an ongoing condition, you may be eligible to receive full or partial coverage to purchase the full cranial prosthesis by your health insurance company.