Measurement of three-joint-finger motions: reality or fancy? A three-dimensional anatomical approach.

Various anatomical publications have reported two-dimensional studies with flexion/extension or abduction/adduction motion analysis, but longitudinal axial rotations (LAR) of three-joint fingers have rarely been mentioned. The aim of our study was to determine the maximal passive motions of three-joint-fingers and to measure the passive LAR of phalanges during a flexion/extension movement. A protocol of anatomical dissection was carried out with 22 fresh-frozen limbs from 11 human cadavers free from any visible pathology. The sample consisted of six females and five males with a mean age of 75.7 years (range 65-94 years). Passive motions of fingers excluding the thumb were analyzed with a wire circling technique. Extreme flexion/extension angles and adduction/abduction laxities were measured for each joint. LAR angles of distal bony segment position were evaluated in comparison with the proximal bony segment position in extreme flexion or extension. The results were recorded for the joints of each three-joint-finger. No difference was statistically related to sex or right/left-sided criteria ( p>0.05). Passive LARs were measured in spite of an aggressive anatomical protocol. A small database was set up. LARs were an important third type of motion. They should be analyzed during a routine clinical examination of patients' hands as well as flexion/extension or abduction/adduction motions.