RESUMEN
Stability of the thumb carpometacarpal joint relies upon equilibrium between its ligaments, muscular support and joint congruity. We wanted to identify the muscles important in preventing or increasing dorsoradial subluxation of this joint. In ten cadaveric hands, a Fastrak® motion tracking device was used to assess the effects of individual isometric muscle loading on the base of the thumb metacarpal relative to the radius and to the base of the middle finger metacarpal. We found that the first dorsal interosseous muscle caused the least dorsoradial translation and highest distal migration of the base of the first metacarpal, whereas abductor pollicis longus was the primary destabilizer, increasing dorsoradial misalignment. The findings show different impacts of these muscles on joint alignment and stability, which suggests that treatment should be targeted to enhance the action of the primary stabilizing muscle, the first dorsal interosseous muscle.
Asunto(s)
Articulaciones Carpometacarpianas/fisiología , Contracción Isométrica/fisiología , Luxaciones Articulares/fisiopatología , Huesos del Metacarpo/fisiología , Músculo Esquelético/fisiología , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos/fisiología , Cadáver , Femenino , Humanos , Masculino , Pulgar/fisiologíaRESUMEN
Carpal stability has traditionally been defined as dependent on the articular congruity of joint surfaces, the static stability maintained by intact ligaments, and the dynamic stability caused by muscle contractions resulting in a compression of joint surfaces. In the past decade, a fourth factor in carpal stability has been proposed, involving the neuromuscular and proprioceptive control of joints. The proprioception of the wrist originates from afferent signals elicited by sensory end organs (mechanoreceptors) in ligaments and joint capsules that elicit spinal reflexes for immediate joint stability, as well as higher order neuromuscular influx to the cerebellum and sensorimotor cortices for planning and executing joint control. The aim of this review is to provide an understanding of the role of proprioception and neuromuscular control in carpal instabilities by delineating the sensory innervation and the neuromuscular control of the carpus, as well as descriptions of clinical applications of proprioception in carpal instabilities.
Asunto(s)
Articulaciones del Carpo/inervación , Articulaciones del Carpo/fisiopatología , Inestabilidad de la Articulación/fisiopatología , Articulaciones del Carpo/cirugía , Humanos , Inestabilidad de la Articulación/terapia , Ligamentos Articulares/inervación , Ligamentos Articulares/fisiopatología , Ligamentos Articulares/cirugía , Mecanorreceptores/fisiología , Procedimientos Ortopédicos , Aparatos Ortopédicos , Modalidades de Fisioterapia , Propiocepción/fisiología , Reflejo/fisiología , Articulación de la Muñeca/inervación , Articulación de la Muñeca/fisiologíaRESUMEN
The morphological structure of the seven components of triangular fibrocartilage complexes of 11 cadaver wrists of elderly people was assessed microscopically, after staining with Hematoxylin-Eosin and Elastica van Gieson. The articular disc consisted of tight interlaced fibrocartilage without blood vessels except in its ulnar part. Volar and dorsal radioulnar ligaments showed densely parallel collagen bundles. The subsheath of the extensor carpi ulnaris muscle, the ulnotriquetral and ulnolunate ligament showed mainly mixed tight and loose parallel tissue. The ulnolunate ligament contained tighter parallel collagen bundles and clearly less elastic fibres than the ulnotriquetral ligament. The ulnocarpal meniscoid had an irregular morphological composition and loose connective tissue predominated. The structure of the articular disc indicates a buffering function. The tight structure of radioulnar and ulnolunate ligaments reflects a central stabilizing role, whereas the ulnotriquetral ligament and ulnocarpal meniscoid have less stabilizing functions.