China
Africa
Explore chapters and articles related to this topic
Designing for Upper Torso and Arm Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The clavicle articulates distally with the acromion of the scapula at the acromioclavicularjoint, a synovial gliding joint. The acromion is the bony upper shelf of the scapula that sits above the humeral head of the upper arm. You can palpate it as a ridge about 2 cm (.8 in.) in length—the size varies person to person. The acromial point, the lateral tip of the acromion, is an often-used landmark spot to position wearable product features. For example, the acromial point corresponds to the top point of the cap of a set-in sleeve (Figure 4.18).
Development of a more biofidelic musculoskeletal model with humeral head translation and glenohumeral ligaments
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Sujata Khandare, Meghan E. Vidt
The shoulder complex is an intricate combination of four joints, including the glenohumeral joint, acromioclavicular joint, sternoclavicular joint, and scapulothoracic joint. The glenohumeral (GH) joint which possesses 6 degrees of freedom (DOF), 3 rotations and 3 translations, is often considered as an ingenious compromise between stability and mobility (Veeger and van der Helm 2007; Wilk et al. 1997). The glenoid fossa, a relatively flat surface, does very little to limit humeral head translation (HHT), given that the surface area of the humeral head is ∼3 times that of the glenoid fossa (Soslowsky et al. 1992). HHT in healthy shoulders is believed to be small in magnitude, due to the centering effect of rotator cuff forces positioning the humeral head on the glenoid (Graichen et al. 2000). However, abnormal HHT, specifically superior and anterior translations, or abnormal scapular motions are often proposed as detrimental kinematics responsible for subacromial space reductions in shoulder impingement syndrome (Sharkey and Marder 1995; Wong et al. 2003), leading to impingement of the rotator cuff muscles (Paletta et al. 1997; Ludewig and Cook 2002). However, Michener et al. (2003) stated that it is uncertain whether rotator cuff injury causes subacromial impingement, or if reduced subacromial space causes rotator cuff injury.
Self-selected running gait modifications reduce acute impact loading, awkwardness, and effort
Published in Sports Biomechanics, 2021
Haisheng Xia, Yangjian Huang, Gang Chen, Sulin Cheng, Roy T. H. Cheung, Peter B. Shull
Reflective markers were placed at specific body landmarks according to the modified Vicon Plug-in Gait lower body model (Vicon Motion Systems Ltd, 2002), and additional markers were placed at the C7 (spinous process of the seventh cervical vertebra), LSHO (acromioclavicular joint of left shoulder) and the RSHO (acromioclavicular joint of right shoulder) for capturing trunk motion. Marker trajectories were collected at 100 Hz via a 16-camera motion capture system (Vicon, Oxford, UK). Ground reaction force data were collected at 1,000 Hz via an instrumented treadmill (Bertec, Columbus, OH, USA). An inertial measurement unit (Xsens MTI300, Xsens North America Inc., CA, USA) was securely affixed to the anteromedial aspect of distal right tibia, and the x-axis was aligned with the longitudinal direction of the tibia to record peak tibial acceleration (PTA) (Crowell et al., 2010) at 1,000 Hz.
Optimal mass of the arm segments in throwing: A two-dimensional computer simulation study
Published in European Journal of Sport Science, 2021
Patrick Fasbender, Thomas J. Korff, Vassilios B. Baltzopoulos, Nicholas P. Linthorne
As highlighted previously, high-speed overarm throwing is a complex three-dimensional movement. Therefore, we recommend further computer simulation studies be conducted using three-dimensional models of the human body. Musculoskeletal models of the human body have been developed using software such as SIMM, OpenSim, and MSMS, and used to investigate walking, running, jumping, and lifting. Such software packages can also be used to develop models of throwing. However, issues over the accuracy of the throw simulations might arise due to the very high mobility of the shoulder complex (clavical, scapula, humerus, glenohumeral joint, acromioclavicular joint, and sternoclavicular joint). Accurate experimental data is needed to validate a simulation model (Hicks, Uchida, Seth, Rajagopal, & Delp, 2015), but there may be concerns over the accuracy of motion data for the scapula and angular velocity data for the longitudinal rotation of the humerus. A computer simulation study of high-speed throwing using a three-dimensional musculoskeletal model is likely to be more difficult to conduct than a study of simpler movements such as walking.