Fingertip forces and completion time for index finger and thumb touchscreen gestures

Effect of object width on muscle and joint forces during thumb-index finger grasping.

The objective of this study was to identify the impact of modifying the object width on muscle and joint forces while gripping objects. The experimental protocol consisted to maintain horizontally five objects of different widths (3.5, 4.5, 5.5, 6.5, and 7.5 cm) with a thumb-index finger grip. Subjects were required to grasp spontaneously the object without any instruction regarding the grip fo...

Directional Coordination of Thumb and Finger Forces during Precision Pinch

The human opposable thumb enables the hand to perform dexterous manipulation of objects, which requires well-coordinated digit force vectors. This study investigated the directional coordination of force vectors generated by the thumb and index finger during precision pinch. Fourteen right-handed, healthy subjects were instructed to exert pinch force on an externally stabilized apparatus with t...

Handedness and index finger movements performed on a small touchscreen.

Many studies of right/left differences in motor performance related to handedness have employed tasks that use arm movements or combined arm and hand movements rather than movements of the fingers per se, the well-known exception being rhythmic finger tapping. We therefore explored four simple tasks performed on a small touchscreen with relatively isolated movements of the index finger. Each ta...

Variations in the nerves of the thumb and index finger.

The digital nerves to the thumb and index finger have been studied by dissecting twenty-five embalmed upper limbs. The palmar digital nerves to the thumb were constant in position and course, with a short lateral cutaneous branch from the radial palmar digital nerve in 30 per cent of cases. The palmar digital nerves to the index finger had a variable pattern, the commonest arrangement, well des...

Thumb and finger sucking.