From the National Federation of State High School Associations (NFHS) Soccer Rules Committee:

INDIANAPOLIS, IN (March 23, 2010) — The official signals used for high school soccer have been modified to reflect common practice. This was one of 11 changes approved by the National Federation of State High School Associations (NFHS) Soccer Rules Committee at its January 25-27 meeting in Indianapolis. The rules changes subsequently were approved by the NFHS Board of Directors. The committee approved a reduction in the number of signals from 23 to eight, effective with the 2010-11 season. The eight signals that were retained are the most common signals used by officials at all levels of play.

Read the rest of the press release here.