A person commits the offense of misdemeanor assault if he intentionally, knowingly, or recklessly causes bodily injury to another. TEX. PEN. CODE ANN. 22.01(a)(1). A person commits the offense of aggravated assault if he commits misdemeanor assault and either: (1) causes serious bodily injury to another, or (2) uses or exhibits a deadly weapon during the commission of the assault. TEX. PEN. CODE ANN. 22.02(a). "Serious bodily injury" is any injury that "creates a substantial risk of death or that causes death, serious permanent disfigurement, or protracted loss or impairment of the function of any bodily member or organ." TEX. PEN. CODE ANN. 1.07(a)(46).