Detailed anatomy of the extensor mechanism at the proximal aspect of the finger.
To explain the unique action of the lateral bands during flexion and extension of the finger, a study was undertaken to examine the extensor mechanism at the level of the proximal interphalangeal joint. The study was carried out in three stages-histologic, anatomic, and dynamic. The histologic sections showed no elastic tissue present to account for the expansile and contractile movement of the lateral bands. The anatomic and dynamic studies showed that the extensor mechanism at the level of the proximal aspect of the finger was composed of an intricate, layered, crisscross fiber pattern which altered its geometric arrangement as the finger was flexed and extended. It is our opinion that the action of the crisscross fibers may govern both the action and degree of displacement of the lateral bands during flexion and extension of the finger.
D002102:Cadaver; D004547:Elastic Tissue; D005384:Finger Joint / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D013710:Tendons / Q000033:anatomy & histology* / Q000502:physiology