The Musculoskeletal System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
A dislocation, also known as a luxation (or when incomplete, a subluxation) occurs when two articulating surfaces become separated as a result of injury, associated disease, or a congenital disorder. It occurs most often in the shoulder joint and occasionally in the jaw. A sprain is the tearing of ligaments associated with sudden wrenching of a joint. This occurs most often in the ankle and is associated with loss of mobility and discoloration of the skin caused by hemorrhaging into the surrounding tissue. Carpal tunnel syndrome (CTS) occurs when the wrist ligament compresses the median nerve where it passes (tunnels) between the ligament and bones and tendons of the wrist (carpus).
Bones and joints
David Heylings, Stephen Carmichael, Samuel Leinster, Janak Saada, Bari M. Logan, Ralph T. Hutchings in McMinn’s Concise Human Anatomy, 2017
Carpal bones - bones of the wrist. The eight small carpal bones each have their own characteristic sizes and shapes, details of which need not be learned. The important point is to remember the order of the bones in the two rows of four from the lateral to the medial side: in the proximal row, the scaphoid, lunate, triquetral and pisiform bones; and in the distal row, the trapezium, trapezoid, capitate and hamate bones. The scaphoid, lunate and triquetral bones articulate with the distal radius, forming the wrist joint (Fig.4.15). The most important carpal bones are the scaphoid (most commonly fractured) and the lunate (most commonly dislocated). The trapezium and the base of the first metacarpal make the carpometacarpal joint of the thumb the most important of the carpometacarpal joints.
Carpal fractures and dislocations
Charles M Court-Brown, Margaret M McQueen, Marc F Swiontkowski, David Ring, Susan M Friedman, Andrew D Duckworth in Musculoskeletal Trauma in the Elderly, 2016
Two rows of eight bones make up the carpus, with the proximal row including the scaphoid, lunate and triquetrum. The distal row is made up of the trapezium, trapezoid, capitate, hamate and pisiform. The proximal carpal row is known as the key intercalated segment, bridging between the bones of the forearm and the distal row of the carpus and the metacarpals33,52–54 which delivers movement, congruency and force transmission at the wrist joint.26,55,56 The intrinsic and extrinsic ligaments of the wrist are essential to allowing a degree of movement while maintaining stability.35,55,56 The intrinsic ligaments connect individual carpal bones to one another, while the extrinsic ligaments connect the carpal bones to the forearm bones and the metacarpals.26 Defining these ligaments can be difficult clinically as they often merge with the articular surface and capsule of the wrist, and a recent review of 58 anatomical studies found that all but one of the carpal ligaments are not described consistently.57
A new musculoskeletal AnyBody™ detailed hand model
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Lucas Engelhardt, Maximilian Melzner, Linda Havelkova, Pavel Fiala, Patrik Christen, Sebastian Dendorfer, Ulrich Simon
Although Eschweiler et al. (2016) had already developed a detailed model of the human wrist within the AMS, this model is not implemented in the proposed detailed hand model, mainly because of the reduction of complexity of the model. The eight carpal bones in the presented model are defined as one rigid segment, allowing no movement between the carpal bones. When the research questions do not address the force distribution inside the wrist joint, Schuind et al. (1995) showed that this lack does not have a great influence on the outcome of the muscle activities. This limitation can be addressed in a future version of the model, where splitting of the wrist joint into an ulnar and radial side might be convenient. Further enhancements might be the implementation of helical joint axes in the thumb joints, as proposed by Kerkhof et al. (2016).
Student perceived impact of a physical, kinetic and interactive model
Published in Journal of Visual Communication in Medicine, 2019
Erica Reneé Malone, Glenda Bingham, Jinsil Hwaryoung Seo, Michelle D. Pine
Bones created for this model had to be light enough to allow for movement and easy manipulation, but also required sufficient stability to withstand the attachment and pull of the strings representing muscles. Rubber moulds were made for a complete canine left thoracic limb using Alumilite Quick-Set mould making rubber (Alumilite Corp., Kalamazoo, MI). These included the scapula, humerus, radius, ulna, carpal bones (6), metacarpal bones (5) and phalanges (14). The moulds were then used to create plastic casts of the bones (Alumilite Super Plastic Casting resin, Alumilite Corp., Kalamazoo, MI). Whether casts were made from articulated or disarticulated bones was determined based on the movement necessary. As the shoulder and elbow joints had to be freely moveable hinge joints, the scapula, humerus, ulna and radius were cast individually. For the purposes of demonstrating flexion and extension at the level of the carpus, only movement at the antebrachial carpal joint was necessary. Therefore, the entire carpus was cast as a single piece. The metacarpus was also cast as a single unit. To allow for demonstration of movement of the digital joints, individual casts for the phalanges of only the fifth digit (fifth proximal, middle and distal phalanges) were created. Instructors felt that the concepts the students were expected to learn could be illustrated on a single digit, so the phalanges of the remaining digits, digits 1–4, were cast as four individual units. Examples of the mould and cast for the humerus are shown in Figure 2.
Cross-sectional changes of the distal carpal tunnel with simulated carpal bone rotation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
The changes of the carpal tunnel cross-section have been studied with respect to carpal bone motion. In a cadaveric study, wrist forces were applied to cadaveric hand specimens and the carpal tunnel cross-section was digitally imaged and analyzed (Bueno-Gracia, Pérez-Bellmunt, et al. 2018). In an in-vivo study, external forces were manually applied to participant wrists and the resulting changes in carpal tunnel morphology were measured via ultrasound (Bueno-Gracia, Ruiz-de-Escudero-Zapico, et al. 2018). These studies showed that the application of wrist forces causing carpal bone motion can increase the cross-sectional area, increase the anterior-posterior diameter and decrease the transverse diameter. Analogous comparisons to the current study can be made regarding the total CSA, which was observed to decrease for all rotation axes excluding CR. Differences can potentially be explained in the bone mobilization method. The external mobilization method employed by Bueno-Gracia et al. (Bueno-Gracia, Pérez-Bellmunt, et al. 2018; Bueno-Gracia, Ruiz-de-Escudero-Zapico, et al. 2018) may have involved bone translation and rotation, as well as the motion of additional carpal bones, aside from just the hamate and trapezium.