Thumb Metacarpophalangeal Joint. Part I: Anatomy, Biomechanics, and Imaging Techniques

The thumb metacarpophalangeal joint (MCPJ) is a diarthrodial joint permitting flexion, extension, adduction, abduction, pronation, and supination. Its mobility and stability differ significantly from those of the metacarpophalangeal joints of the long fingers. Stability predominates over mobility in this joint and is ensured by a complex interplay of capsuloligamentous, osteochondral, and both intrinsic and extrinsic musculotendinous structures. These components can be comprehensively evaluated using various imaging modalities. Soft tissues, including ligaments, tendons, aponeuroses, pulleys, and the volar plate, can be visualized particularly well using high-resolution ultrasound (US) and high-field magnetic resonance imaging (MRI).

This educational review delineates the anatomy, physiology, and biomechanics of the thumb MCPJ, emphasizing the mechanisms underlying joint stability using high-resolution US and high-field MRI.

A thorough understanding of the anatomy, physiology, and biomechanics of the thumb MCPJ is essential for accurate assessment of its pathologies. Such knowledge facilitates appropriate therapeutic decision-making and helps prevent significant functional impairment, in both the general population and among high-performance athletes.

· The thumb metacarpophalangeal joint emphasizes stability through coordinated structural interactions.. · Dynamic ultrasound and high-resolution MRI allow detailed anatomical assessment.. · Functional anatomy knowledge is essential for diagnosing collateral ligament injuries.. · Soft-tissue imaging guides treatment decisions and prevents functional sequelae..

· Bouredoucen H, Taihi L. Thumb Metacarpophalangeal Joint. Part I: Anatomy, Biomechanics, and Imaging Techniques. Rofo 2026; DOI 10.1055/a-2834-3432.