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Finger flexor motor control patterns during active flexion: an in vivo tendon force study
Mina Nikanjam1, Katarzyna Kursa, Steve Lehman
1Department of Bioengineering, University of California, San Francisco, United States.
Human Movement Science
|December 19, 2006
Summary
Finger flexion motor control varies with wrist position. The flexor digitorum profundus (FDP) tendon initiates movement differently based on wrist angle, impacting index finger control.
Area of Science:
- Biomechanics
- Neuroscience
- Orthopedic Surgery
Background:
- Understanding index finger flexor motor control is crucial for rehabilitation after hand injuries.
- Previous studies often lack in vivo tendon force data during dynamic movements.
- The interplay between wrist posture and finger flexion mechanics requires further investigation.
Purpose of the Study:
- To measure in vivo index finger flexor tendon forces during active finger flexion.
- To evaluate how different wrist angles affect motor control patterns of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons.
- To characterize concurrent joint angle changes with tendon force dynamics.
Main Methods:
- Utilized an in vivo tendon force measurement system with buckle force transducers.
- Instrumented FDP and FDS tendons during open carpal tunnel release surgery (N=12).
- Participants performed active finger flexion at neutral (0 degrees) and flexed (30 degrees) wrist angles.
Main Results:
- FDP and FDS tendon force changes were not concurrent with metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint angle changes.
- No consistent FDS tendon force changes were observed across participants.
- Two distinct FDP tendon force patterns emerged: initiation without force followed by FDP force in neutral wrist, and initiation/continuation with FDP force in flexed wrist.
Conclusions:
- Index finger flexor motor control is significantly influenced by wrist posture.
- The flexor digitorum profundus (FDP) plays a key role in initiating and executing finger flexion, with its activation pattern dependent on wrist angle.
- Passive forces can contribute to initiating finger flexion, subsequently replaced by active FDP force.
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