Congress passed legislation in 1965 that established the Medicare program as Title XVIII of the Social Security Act. The 1965 amendments to the Social Security Act established two separate but coordinated health insurance plans for persons aged 65 or older. The compulsory Hospital Insurance (HI) program is Part A of Medicare, and a voluntary program of Supplementary Medical Insurance (SMI) is Part B
In 1972, Section 273 of the Social Security Amendment (P.L. 92-603) expanded the definition of physician under Part B of Medicare to include chiropractors. This made chiropractors eligible to participate in the Medicare program. However, the only Medicare reimbursable chiropractic treatment is manual manipulation of the spine to correct a subluxation demonstrated by X-ray.
Medicare benefit payments totaled $597 billion in 2014. Of that total, $68.6 Billion was for Physicians and other health professionals, and about $500 Million was for services to about 2 Million Medicare beneficiaries provided by about 45,000 Doctors of Chiropractic. The reimbursements for the only three CPT codes payable for chiropractic services amount to .000837 ( or .08 % ) of the total Medicare expenditures, and just .00728 ( or .72 % ) of the total reimbursements to physicians.