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Hands and Handles
Published in Stephen Pheasant, Christine M. Haslegrave, Bodyspace, 2018
Stephen Pheasant, Christine M. Haslegrave
The forearm has two long bones — the radius and ulna — which run from the elbow to the wrist and articulate with each other at their top and bottom ends. When the hand is in its palm up or supine position, these two bones are parallel. (The radius is on the thumb side; the ulna is on the little finger side.) As the hand is turned into the palm down or prone position, the lower end of the radius rotates about the axis of the ulna and the shafts of the two bones cross — a movement which can be felt when lightly holding your arm just above the wrist. Note then that the movements of pronation and supination occur at the two articulations between the radius and ulna rather than at the wrist as such. In practice, however, the natural hand movements we use in everyday life often entail actions of pronation and supination in combination with movements occurring at the wrist.
Cumulative Trauma
Published in Ronald Scott, of Industrial Hygiene, 2018
There are two bones in the forearm, the ulna and the radius. These meet at the elbow with the humerus, the bone of the upper arm. When the arm is bent or straightened, the ulna and humerus operate at the elbow like a hinge. The wrist is attached to the ends of the ulna and radius. It is moved up and down by muscles in the forearm. Extending the wrist (moving it from down to a neutral position), as would be done in a tennis backhand stroke, stresses the tendon attaching the muscle performing that movement at its attachment to the humerus in the region of the elbow. Inflammation at that attachment by strong repetition of the backhand movement in tennis causes epicondylitis, nicknamed “tennis elbow”. Extending the wrist is a common motion in numerous tasks. Frequent or forceful repetition can, just as with tennis players, produce this inflammation.
Robotic Arm Control
Published in Ferat Sahin, Pushkin Kachroo, Practical and Experimental Robotics, 2017
There are three links in this robot: Base link: This is the link between the base and the shoulder.Arm: This is the link between the shoulder and the elbow joints.Forearm: This is the link between the elbow and the wrist joints.
Classification of forearm EMG signals for 10 motions using optimum feature-channel combinations
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Muhammad Shahzaib, Sadia Shakil, Sajid Ghuffar, Moazam Maqsood, Farrukh A. Bhatti
There are eight flexor muscles that control the flexion of fingers, wrist and pronation of forearm. These muscle are further divided into two groups; deep and superficial muscles. The channel placement on muscles is shown in Table 3. Channel one is placed on FCU, which helps in wrist flexion, wrist deviation (towards the ulnar bone) and some degree of flexion of ring and little finger as well. Channel two is placed on FDS muscles that control the flexion of fingers (up to the digits). Channel three is placed on the overlapping FDS and FDP muscles that control the finger flexion motion. Channel four, placed on FPL, is responsible for thumb motion. Channel five is placed on BR muscle which is used to capture the wrist extension motion. A reference electrode is placed on Olecranon (Adewuyi et al. 2016) (elbow).