M.Tech. (Chiropractic) / The most accepted method of identifying the second sacral spinous process is by using an accepted landmark known as the Posterior Superior Iliac Spines (PSIS). The PSIS lies about 4cm lateral to the second spinous tubercle of the sacrum (Williams and Warwick, 1980). However, in a search of published work, no evidence could be found of any study which established these generally accepted statements (Stonelake, 1983). This was an inter-examiner reliability study aimed to determine whether palpation of the PSIS was a reliable and accurate method of determining the location of the second sacral spinous process (S2) in participants experiencing lumbosacral joint dysfunction. Thirty participants were marked by three examiners in the prone position using the PSIS to locate S2. An x-ray was taken of each participant in the prone position, after being marked by all three examiners. Measurements were then made on the x-rays to assess the location of the markers on the sacral anatomy. The reliability. of palpation of anatomical landmarks needs to be validated further in future studies, as motion palpation and the palpatory assessment of effectiveness of treatment, applied to correct motion restrictions, are predicted- upon accurate localisation of anatomical landmarks (O'Haire and Gibbons, 2000).