The effect of blocking radial abduction on palmar abduction strength of the thumb

Abstract

The measurement of palmar abduction strength of the thumb (PAST) is often used as a research tool to provide an objective assessment of thenar muscle function in patients with carpal tunnel syndrome (CTS). The purpose of this study is to determine the effect of blocking radial abduction on PAST in a normal population. PAST was measured for both hands of 100 healthy volunteers in two positions. In the first position a vertical board was placed perpendicular to the radial border of the hand to block radial abduction, and in the second position PAST was measured without the board. Men had greater PAST. There was no difference in PAST between the dominant and non-dominant hand for both men and women, when a vertical board was used. Without the board, the values were significantly greater in the dominant hand. Radial abduction should be blocked during measurement of PAST.

A Comparison of the Reliability of Make Versus Break Testing in Measuring Palmar Abduction Strength of the Thumb

“…There were seven previous studies that measured thumb abduction strength in normal subjects [1,[6][7][8][9][10][11] and we have summarized six of them in a previous publication [1]. There was great variation in the results of PAST obtained between the different studies even when a similar method of testing was used, ranging from 1.50 kg for the right hand (without specification of hand dominance or gender) [6] to 6.16 kg in the dominant hand of male participants [1]. This highlighted the importance of standardizing the position to produce reliable and comparable results.…”

“…Three of them used the 'break' test method [1,7,10] whereas two used the 'make' test method [6,9]. In addition, four studies measured PAST with the hand in the supine position [1,6,8,10], one measured PAST with the hand in the prone position [7], while Chao et al [9] did not specify the position of the hand during testing. Rozmaryn et al [11] measured isometric thumb strength with the thumb abducted to 45°which is neither a 'make' nor a 'break' test.…”

“…It is a useful research tool in patients with carpal tunnel syndrome (CTS). We have previously reported on normative values of PAST in our population [1]. In our previous study, we realized that PAST could be measured using a 'make' test or a 'break' test.…”