Imaging of the metacarpophalangeal joints of the long fingers: frequent and uncommon pathologies with imaging findings.

Disorders affecting the metacarpophalangeal joints of the long fingers are relatively uncommon and often under-recognized compared to those involving the thumb. This review provides a comprehensive and structured overview of a broad spectrum of pathologies involving these joints, including fractures, ligament sprains, joint instabilities and dislocations, sagittal band injuries, boxer's knuckle, lesions of the deep transverse metacarpal ligament, muscle disorders, trigger finger, mechanical locking, arthropathies, avascular necrosis of the metacarpal head (Dieterich's disease), and tumors. Special attention is given to the diagnostic contributions of various imaging modalities: high-resolution Magnetic resonance imaging allows for detailed anatomical assessment; dynamic ultrasound improves lesion evaluation through real-time biomechanical analysis; and radiography, Computed tomography, and cone-beam computed tomography offer precise characterization of osseous involvement. Practical recommendations are provided to emphasize the clinical relevance of imaging findings and to offer clear guidance for their application in patient care. Accurate imaging-based identification of these conditions is essential for timely diagnosis and effective treatment. This review aims to support radiologists and clinicians in daily practice and to promote further research in this specialized and evolving field of musculoskeletal imaging.