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Designing for Hand and Wrist Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
Muscle actions across the MP and IP joints of the thumb flex and extend the tip of the thumb with each of the CMC movements. Move your L thumb and longest finger distally along the R thumb to the large joint (MP joint) between the metacarpal and the proximal phalanx. Bend and straighten your R thumb—observe the MP joint range of motion—90 degrees of flexion with 0 degrees extension (to neutral). Then see that the IP joint, the most distal joint of the thumb, has a range of motion from 90 degrees of flexion to 20 degrees of extension (Figure 7.18, B). The thumb also rotates due to a combination of the CMC motions, to allow opposition of the thumb tip to fingers II-V. When the thumb is in opposition, the thumb metacarpal is abducted in the plane perpendicular to the palm—the MP joint is flexed, and the IP joint may be flexed or extended.
Musculoskeletal system
Published in David A Lisle, Imaging for Students, 2012
Radiographic signs of RA (Fig. 8.57): Soft tissue swelling overlying jointsBone erosions occur in the feet and hands, best demonstrated in the metatarsal and metacarpal heads, articular surfaces of phalanges and carpal bonesReduced bone density adjacent to joints (periarticular osteoporosis)Abnormalities of joint alignment with subluxation of metacarpophalangeal joints causing ulnar deviation of fingers, and subluxation of metatarsophalangeal joints producing lateral deviation of toes.
Fundamentals of Infrared Thermal Imaging
Published in U. Snekhalatha, K. Palani Thanaraj, Kurt Ammer, Artificial Intelligence-Based Infrared Thermal Image Processing and Its Applications, 2023
U. Snekhalatha, K. Palani Thanaraj, Kurt Ammer
Radius fracture is a frequent initial injury triggering the development of CRPS. Ammer (1991a), conducted a study on patients, whose plaster fixation was removed due to radiographic signs of bone healing (Ammer, 1991a). Thermal images were recorded immediately after removal of the fixation and a week later, radiography of the distal forearm and the hand skeleton was performed. Radiographs were evaluated for early signs of algodystrophy, which were found in 21 of 41 patients. Mean skin temperature in an area of the wrist and the hand dorsum was based on 10 spot temperatures located at the wrist and the midpoint of each metacarpal bone. Side-to-side temperature difference (affected side minus non-affected side) was calculated. At baseline, the hand temperature on the injury side was 32.8 ± 1.4°C and 31.9 ± 1.7°C on the control side. A week later, the mean temperature of the injured arm decreased to 32.6 ± 1.2°C, while the non-injured control remained at a temperature of 31.9 ± 1.2°C. At baseline, the fractured radius site was in radiographically positive CRPS cases by 1.2°C warmer than the control side. Diagnostic sensitivity, and specificity for radiographic signs of algodystrophy was calculated at each time point for a temperature difference threshold of 0.6 and 1.6°C, respectively. At baseline, the diagnostic sensitivity of temperature difference ≥0.6° was 71.4% and specificity was 45%. Increasing the threshold to 1.6°C resulted in a decrease of sensitivity to 33% and an increase of specificity to 95%. Based on these results, it was hypothesized that persistent hyperthermia after bone injuries may promote bone dystrophy in CRPS patients.
Employing a three-stage procedure to develop a sizing system for medical gloves
Published in Ergonomics, 2022
Asma Zare, Mehdi Jahangiri, Mozhgan Seif, Alireza Choobineh
According to Table 4, middle finger length, palm length, and circumference at metacarpal accounted for a higher variance of the overall hand size (4.059, 4.013, and 4.011%, respectively) compared to other dimensions. In addition, hand breadth at metacarpals and wrist breadth were higher variance in the shape of the hand (5.461 and 5.350%, respectively) compared to other dimensions. Using a weighted approach (i.e. 63.39% for PC1 and 15.27% for PC2) revealed that the most effective factor in defining the size and shape of the hand among Iranian healthcare workers was the middle finger length (4.059% × 63.39 + 2.99% × 15.27 = 3.005; Table 4). Overall, middle finger length, palm length, circumference at metacarpal, hand breadth at metacarpals, and wrist breadth were the most distinctive features of the hand in determining hand size among healthcare workers. So the parameters were useful for inclusion in the design of glove size.
The relationship between changes in elbow valgus laxity and forearm flexor strength during repetitive pitching
Published in Sports Biomechanics, 2022
Yusuke Namiki, Akira Saito, Kyoji Okada
The maximum isometric strengths (kg) of wrist flexion, radial deviation, and ulnar deviation were measured using a digital handheld dynamometer (Micro Fet II, National Medical Co. Ltd., Chiba, Japan). Each strength was assessed while the participants were seated on a chair with their elbow joint and forearm placed on the bed, and the wrist joint and hand were off the edge of the bed. The wrist flexion strength was measured with the forearm and wrist joint in a neutral position, and the force sensor was applied to the palmar surface of the third metacarpal head (Figure 2(a)). The radial deviation strength was measured with the forearm pronated and the wrist in a neutral position. The force sensor was applied to the radial surface of the second metacarpal head (Figure 2(b)). The ulnar deviation strength was measured with the forearm in the supine position and the wrist joint in a neutral position. The force sensor was applied to the ulnar surface of the fifth metacarpal head (Figure 2(c)).
Development and testing of a wearable wrist-to-forearm posture measurement system for hand-tool design evaluation
Published in International Journal of Occupational Safety and Ergonomics, 2021
Michail Karakikes, Dimitris Nathanael
An issue which is pertinent to the tracking system’s accuracy is the placement of the sensors on the body. Determining the exact location of the sensors is an important task of the system design, since it affects the level of skin artifact occurrence [24], while the complexity of the anatomical structure of joints and body segments has to be taken into account. Using the recommendations of the International Society of Biomechanics regarding joint coordinate systems [31], the following placement was decided: IMU#1 was placed on the dorsal surface of the forearm, close to the elbow joint, where skin displacement during P/S is minimal [32]; IMU#2 was placed on the dorsal surface of the forearm, near the wrist joint (between the radius and the ulna); IMU#3 was placed approximately over the center of the third metacarpal bone of the hand, on the dorsal side (Figure 2).