Intrinsic minus hand posture occurs when which muscles are weak while extrinsic muscles remain intact?

Intrinsic minus hand posture occurs when which muscles are weak while extrinsic muscles remain intact?

• A. Wrist flexion with MCP extension and PIP/DIP flexion
• B. Wrist extension with MCP flexion
• C. Full extension of all joints
• D. Wrist flexion with MCP flexion

Answer: (A)

Intrinsic minus occurs when the intrinsic hand muscles are weak while the extrinsic muscles remain intact. The intrinsic muscles normally flex the metacarpophalangeal joints and help extend the PIP and DIP joints through the extensor mechanism. When they’re weak, the extrinsic extensors pull the MCP joints into extension, and the flexors continue to pull the PIP and DIP joints into flexion because there is no intrinsic force to extend them. This creates the characteristic posture of MCP extension with PIP/DIP flexion, often accompanied by wrist flexion. The described pattern—wrist flexion with MCP extension and PIP/DIP flexion—best matches this mechanism and is the classic presentation of intrinsic minus.

Intrinsic minus occurs when the intrinsic hand muscles are weak while the extrinsic muscles remain intact. The intrinsic muscles normally flex the metacarpophalangeal joints and help extend the PIP and DIP joints through the extensor mechanism. When they’re weak, the extrinsic extensors pull the MCP joints into extension, and the flexors continue to pull the PIP and DIP joints into flexion because there is no intrinsic force to extend them. This creates the characteristic posture of MCP extension with PIP/DIP flexion, often accompanied by wrist flexion. The described pattern—wrist flexion with MCP extension and PIP/DIP flexion—best matches this mechanism and is the classic presentation of intrinsic minus.