Armstrong Teasdale has the largest patent practice in St. Louis, according to the April 16-22 issue of the St. Louis Business Journal. The firm also held the top spot in last year’s list. The paper based the current ranking on the firm’s 34 local patent lawyers and 55 local intellectual property lawyers. In 2009, Armstrong Teasdale assisted local clients in applying for 1,125 patents with 681 local patents granted.