Finger motion required for Auslan: A biomechanical analysis

Background: Australian Sign Language (Auslan) relies heavily on precise finger movements, alongside wrist, forearm, and elbow coordination. Prior studies have examined upper limb biomechanics in Auslan communication but have not quantified the specific range of motion (ROM) required of the fingers. Purpose: To determine the finger ROM necessary for effective Auslan communication, providing evidence to guide rehabilitation strategies for patients reliant on Auslan.

Study Design: Biomechanical analysis Methods: Two right-handed native Auslan communicators were recruited for biomechanical analysis. Reflective markers tracked finger joint movement during the signing of 28 commonly used Auslan phrases, repeated five times each. Data were processed to calculate the coronal, sagittal, and axial ROM for the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints. Descriptive statistics summarized the required ROM and interquartile ranges.

Results: Greater ROM was required in the distal interphalangeal joints of the right index, middle, and ring fingers and the left little finger. Metacarpophalangeal joint motion was comparable bilaterally for the index and middle fingers but was significantly greater on the dominant hand for the ring and little fingers. The right hand demonstrated higher ROM and interquartile ranges overall, reflecting its dominant role in Auslan articulation.

Conclusions: Effective Auslan communication requires greater finger ROM on the dominant hand, particularly for the index, middle, and ring fingers. Rehabilitation strategies should prioritize motion preservation in these joints. Conversely, lower ROM demands on the non-dominant hand suggest motion-sacrificing interventions may be more viable and appropriate for certain joints without compromising function.