China
Africa
Explore chapters and articles related to this topic
Physical Ergonomic Design Aspects of Computer Workstations: A Liechtenstein Perspective
Published in Philip D. Bust, Contemporary Ergonomics 2006, 2020
Els Kessler, Stella Mills, Siegfried Weinmann
None of the users had the keyboard and the mouse at elbow height with their shoulders relaxed and upper arms hanging relaxed to the sides as recommended (e.g. Sanders and McCormick, 1992). In fact, the elbows were constantly resting on the work surface during observation or the arms were resting on the edge of the work surface. These postures can cause the ulnar nerve to be compressed at the point of contact leading to pain at the inner side of the forearm down to the little finger (e.g. Pheasant, 1991). Moreover, when the keyboard is above elbow height, unnecessary strain is exerted in the arm, shoulder and neck muscles, because the shoulders are lifted up or the elbows are raised and spread (Kroemer and Kroemer, 2001). Because all users had fixed desk heights, they were recommended to raise the level of their seats and to place keyboard and mouse within a convenient arm’s reach at elbow height (whilst shoulders and upper arms are relaxed). The four users that were putting documents in front of the keyboard were advised to make use of a document holder (Directive 90/270). In addition, shorter users were recommended to use a footrest (Directive 90/270), if the feet could no longer rest firmly on the floor, since pressure to the underside of the thighs may restrict blood circulation in the lower legs (Bridger, 2003). Shorter users may also sit only on the edge of their seats being unable to lean backward.
Designing for Hand and Wrist Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
Injury to the median nerve is not completely debilitating because the ulnar nerve provides motor control to some of the smaller thenar muscles as well as the many remaining intrinsic hand muscles. The ulnar nerve supplies sensation to the palmar and dorsal hand near the little finger, on to the little finger and the adjacent half of the ring finger. The ulnar nerve is susceptible to compression at the elbow (sometimes referred to as hitting the “crazy bone”) and in the hypothenar palm. Press firmly, beyond the wrist creases and distal to the prominent pisiform (the most proximal carpal bone on the little finger side of the hand). You have found the ulnar nerve in that area when you sense a deep, aching pain.
Chapter 16 Electrophysiology
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
When used in conjunction with EMG recording, nerve conduction measurement is an extremely useful diagnostic tool. The major use of nerve conduction measurements in isolation is in the diagnosis and investigation of entrapment neuropathies. The most common of these is ‘carpal tunnel syndrome’ where compression of the median nerve at the wrist causes an increased latency for both motor and sensory signals. Compression within the tarsal tunnel at the ankle can also be investigated by making MCV measurements. A further use of these measurements is in cases of nerve lesions, e.g. damage to the ulnar nerve at the elbow; stimulation above and below the site of the suspected lesion may show slowing across the lesion.
Forearm muscle activation, ulnar nerve at the elbow and forearm fatigue in overhand sports
Published in Sports Biomechanics, 2020
Lin-Hwa Wang, Kuo-Cheng Lo, I-Ming Jou, Fong-Chin Su
Ultrasonograph with a 5–10-MHz linear-array transducer (SonoSite Inc., Bothell, WA, USA) was used for the examination of the medial elbows. Each participant was seated with the shoulder of the examined arm flexed to 60° and externally rotated to 90°. An assistant helped raise the participants’ wrists to a neutral position, and the ulnar nerve was ultrasonographically examined with the elbow flexed to 45°, 90°, and 120°. Ultrasonographical measurement of the length of the ulnar collateral ligament and its strain was conducted under the valgus stress test. The long-axis diameter and cross-sectional area of the ulnar nerve were examined with elbow flexion at 45°, 90°, and 120°. In transverse images, the value of distances between the ulnar nerve and the tip of the medial epicondyle were identified (positive when the ulnar nerve was located in the cubital tunnel and negative when the ulnar nerve was anteriorly translated onto the medial epicondyle).
MR neurography of the brachial plexus in adult and pediatric age groups: evolution, recent advances, and future directions
Published in Expert Review of Medical Devices, 2020
Alexander T. Mazal, Ali Faramarzalian, Jonathan D. Samet, Kevin Gill, Jonathan Cheng, Avneesh Chhabra
Parsonage- turner syndrome (brachial neuritis) is generally seen as an isolated syndrome and rarely, as a familial variant. The patients typically present with shoulder and neck pain followed by weakness. The C5 and C6 nerves, and upper trunk are the most commonly affected nerves with downstream neuropathy change of the suprascapular nerve and/or axillary nerve. T2 hyperintense signal will be observed in affected root, trunk, and cord segments. Diffuse increased T2 signal intensity will also be seen in regional musculature, alongside other muscle denervation changes, such as fatty replacement and atrophy. Uncommonly, one may also detect torsion of the nerve segment(s) leading to a triple B sign or Bull’s eye sign [61,62]. The ulnar nerve is the least commonly affected nerve in brachial neuritis.
Future technology on the flight deck: assessing the use of touchscreens in vibration environments
Published in Ergonomics, 2019
Louise V. Coutts, Katherine L. Plant, Mark Smith, Luke Bolton, Katie J. Parnell, James Arnold, Neville A. Stanton
Finally, the Cornell University Questionnaire for Ergonomic Comfort was employed to assess the effect of undertaking the tasks on regional discomfort and pain. The questionnaire asks participants to report the frequency with which they experienced pain in different parts of the body (neck, shoulder, upper back, upper arm, elbow, lower back, forearm and wrist) and seven areas of the hand (fingers relating to the (i) median nerve and (ii) ulnar nerve, thumb, upper palm, lower palm in the regions of the (i) lower thumb metacarpal and (ii) carpal bones and the dorsal surface in the region of the metacarpals), the level of discomfort experienced and whether or not the discomfort interfered with work tasks. For each individual part of the hand and body, there are three sub-scales: the first sub-scale measures the frequency with which the participant experiences discomfort on a five-point scale (0–4); the sec sub-scale measures the level of discomfort (if any) on a three-point scale (1–3) and the third sub-scale measures the level of interference of the discomfort with work on a three-point scale (1–3). The scores for the three sub-scales are multiplied to produce a weighted estimate of discomfort for each hand and body part and then summed to produce overall discomfort scores for hand and body posture.