Kantonsspital St.Gallen
login

Physical equilibrium of the normal wrist and its relation to clinically defined "instability"

Vilijam Zdravkovic, H A Jacob & G R Sennwald

abstract The rotational stability of the proximal carpal row was tested on six unembalmed human cadaver hand specimens. The physiological load conditions were stimulated by loading the wrist flexor and extensor tendons. Pure torque was introduced to the lunate, scaphoid and triquetrum, one at a time, by means of a dynamometer wrench, forcing the bones loaded to perform a flexion-extension motion. A truly stable state of equilibrium could be found in the normal wrist only under axial load. A uni-directional coupling was observed through the scapho-lunate ligament as a counteraction to a tendency for the lunate to extend and the scaphoid to flex. The triquetrum and lunate moved together, showing close coupling in both directions. As conclusion: a stable wrist can be defined as one which, while being loaded within a physiological range of stress, does not deviate from a stable state of equilibrium (the ability to return to a single position when disturbed) at any point within the whole physiological range of motion.
   
citation Zdravkovic V, Jacob H A, Sennwald G R. Physical equilibrium of the normal wrist and its relation to clinically defined "instability". J Hand Surg Br 1995; 20:159-64.
   
type journal paper/review (English)
date of publishing 4-1995
journal title J Hand Surg Br (20/2)
ISSN print 0266-7681
pages 159-64
PubMed 7797963