Elsevier

Hand Clinics

Volume 28, Issue 1, February 2012, Pages 1-7
Hand Clinics

Anatomy and Function of the Thenar Muscles

https://doi.org/10.1016/j.hcl.2011.09.006Get rights and content

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Functional movements of the thumb

To fully appreciate the actions of the thenar muscles, the complex motions of the thumb must be understood. Thumb motion is facilitated through the coordination of intrinsic thenar and extrinsic musculature. The thumb musculature dynamically allows for precision pinching and power gripping. Because thumb stability is actively maintained by muscles rather than by articular constraints, most muscles attached to the thumb tend to be active during most thumb motions.3

The opposable thumb is

Anatomy

The most important functional determinant of a muscle is its architecture, the arrangement of muscle fibers relative to the axis of force generation.6 Muscle excursion is directly proportional to muscle fiber length. The force generated by a muscle is directly proportional to its cross-sectional area. Several investigators have studied the various physiologic properties of the thenar muscles and a summary of their findings is found in Table 2, Table 3, Table 4.6, 7

Despite their small size, the

Summary

The functional mobility of the thumb, especially in its action of opposition, is a uniquely human quality. The mobility, strength, and function of the thumb are greatly affected by the actions of the intrinsic muscles of the thumb. These highly specialized muscles, with their variable innervation patterns, help to make the human hand one of the true wonders of the natural world.

Acknowledgments

Special thanks to Dr Steven Green for his valuable insight.

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