Date of download: 10/22/2017 Copyright © ASME. All rights reserved. From: Variable Thumb Moment Arm Modeling and Thumb-Tip Force Production of a Human-Like Robotic Hand J Biomech Eng. 2017;139(10):101005-101005-6. doi:10.1115/1.4037402 Figure Legend: Musculoskeletal structure of the ACT thumb. (a) The joint axes for the ACT thumb's five anatomical degrees-of-freedom including flexion/extension and abduction/adduction of the CMC joint, flexion/extension and abduction/adduction of the metacarpophalangeal (MCP) joint, and flexion/extension of the interphalangeal (IP) joint. (b) Dorsal view of the ACT thumb showing the adductor pollicis longus (ADP), extensor pollicis longus (EPL), abductor pollicis longus (APL), extensor pollicis brevis (EPB) tendons. (c) Palmar view showing the flexor pollicis longus (FPL), flexor pollicis brevis (FPB), opponens (OPP), and abductor pollicis brevis (APB) tendons.