PMC7530478_01
(a) Shiatsu-specific hand posture. (b) When the metacarpophalangeal joint (MCPj) of the ring finger is flexed and deviated ulnarly with concurrent extension of the MCPj of the middle finger, the extensor tendon of the ring finger dislocates ulnarly (white arrowheads).
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fig1
On physical examination, the extensor tendons at the dorsum of the MCPjs of both ring fingers dislocated with a specific hand posture (Figure 1).
Surgical image for the extensor tendon of the ring finger of the left hand. (a) Attenuated radial sagittal band (black arrow). (b) The metacarpal head of the ring finger pops through the attenuated sagittal band (asterisk) with the extensor tendon dislocated ulnarly (black arrowheads) in the shiatsu-specific hand posture.
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fig2
Surgical exploration through a longitudinal curved skin incision at the dorsum of the MCPj of the ring finger revealed a markedly attenuated radial sagittal band and ulnarly dislocated extensor tendons bilaterally (Figure 2).