Abstract：Objective To discuss the effect of interphalangeal joint activity in this area of the extensor tendon and to provide the anatomical basis for the fixed position in the treatment of the Mallet finger through the anatomy study on zone Ⅰ-Ⅱ of extensor tendon in fresh adult specimen of the upper extremity.Methods The maximum passive flexion angle of 2nd-5th distal interphalangeal point (DIPJ) from 16 fresh embalmed cadaver hands were measured with the proximal interphalangeal point (PIPJ) in 0°, 45° and 90° flexion position. The extensor tendon area was exposed in zone Ⅰ-Ⅱ, and then was cut to make a mallet finger model. A Kirsches wire was pierced through the phalanx axis vertically in the middle phalanx neck level as a reference. A mark was made in the extensor tendon for the use of measuring the tendon gliding distance. The broadest gaps between the tendon edges and the tendon gliding distances were measured when the PIPJ was flexed extension 0° to flexion 90° position.Results The maximum passive flexion angle of the DIPJ increased about 21% when the PIPJ was flexed from extension 0° to flexion 90° position. The gap between the extensor tendon edges in zone Ⅱ of forefinger, middle finger, ring finger and little finger were (0.35±0.06)mm, (0.42±0.05)mm, (0.46±0.06)mm, and (0.51±0.08)mm when the PIPJ was in extension 0° position. The proximal side of gap slipped to the distal side and the slipping distance of forefinger, middle finger, ring finger and little finger were(0.69±0.09)mm, (0.74±0.03)mm, (0.80±0.07)mm, and (0.81±0.10)mm when the PIPJ was flexed to 90°.Conclusions When the DIPJ is in mild over extension position and the DIPJ in flexion position, the gap between the tendons edges disappears. The extensor tendon in zone Ⅰ-Ⅱ is loose, and the tension decreases. In the treatment of mallet finger, the above mentioned finger positions can reduce the tension of the tendon, which is beneficial to the healing of the tendon.
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Sun Wentao, Zhang Wenlong, Zhang Jingyu, Dong Liang, Wang Jian.. The applied anatomy of the fixed finger position in the treatment of mallet finger. Chinese Journal of Anatomy and Clinics, 2017, 22(1): 33-36.
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