Mo. Rev. Stat. § 334.686
Any person who holds himself or herself out to be a physical therapist assistant or a licensed physical therapist assistant within this state or any person who advertises as a physical therapist assistant and who, in fact, does not hold a valid physical therapist assistant license is guilty of a class B misdemeanor and, upon conviction, shall be punished as provided by law. Any person who, in any manner, represents himself or herself as a physical therapist assistant, or who uses in connection with such person's name the words or letters, "physical therapist assistant", the letters "P.T.A.", "L.P.T.A.", "C.P.T.A.", or any other letters, words, abbreviations or insignia, indicating or implying that the person is a physical therapist assistant without a valid existing license as a physical therapist assistant issued to such person under the provisions of sections 334.500 to 334.620, is guilty of a class B misdemeanor. This section shall not apply to physicians and surgeons licensed under this chapter or to a person in an entry level of a professional education program approved by the Commission on Accreditation in Physical Therapy Education (CAPTE) who is satisfying supervised clinical education requirements related to the person's physical therapist or physical therapist assistant education while under on-site supervision of a physical therapist; or to a physical therapist who is practicing in the United States Armed Forces, United States Public Health Service, or Veterans Administration under federal regulations for state licensure for health care providers.
§ 334.686, RSMo