Movement analysis of the distal transverse arch of the dominant hand while grasping and pinching objects: A descriptive, correlational research study.

Background: The distal transverse arches obtained from active and passive motions of the hand and the used range of motion (u-ROM) of the hand arch in activities of daily living have rarely been reported.

Purpose: This study aimed to investigate the distal transverse arch angle of the dominant hand, the influence of age, and the u-ROM of the arch when grasping and pinching objects.

Study design: Descriptive and correlational research design.

Methods: The active and passive distal transverse arches of the dominant hand of 104 healthy subjects were measured using a goniometer. Additionally, the hand arch was measured when the subjects grasped and pinched objects. These data were used to analyze the correlation with age and to calculate the u-ROM (u-ROM %) rate of the distal transversal arch. Furthermore, the u-ROM% between the ring and fifth finger components of the hand arch was compared.

Results: The active and passive dorsal arch angles were 135.8 (10.0°) and 169.9 (11.5°), respectively. The distal transverse arch angle tended to decline with age (active: r = -0.18, p = 0.07, 95% confidence interval = -0.36 to 0.02; passive: r = -0.40, p ≤ 0.001, 95% confidence interval = -0.55 to -0.23). The u-ROM% of the hand arch in grasping and pinching ranged from 65.5 (9.8)% to 84.6 (11.6)% and from 52.1 (7.9)% to 67.4 (9.1)%, respectively, against active and passive motions. The ring finger component was significantly higher than the fifth finger component (active: p = 0.08 to <0.001, effect size = -0.17 to -0.69; passive: p ≤ 0.001, effect size= -0.71 to -0.86). A similar trend was observed in both men and women.

Conclusions: Therapists should evaluate the movement of the distal transverse arch of the injured hand in detail and consider the age, sex, and component of the hand arch when intervening.