A 58-year-old man of Northern European descent presents with progressive inability to extend his ring and little fingers. On examination, he demonstrates the clinical finding marked as **C** in the diagram — flexion contracture of the 4th and 5th digits. He cannot lay his hand flat on a table. Which of the following best explains why the ring and little fingers are most commonly affected first in Dupuytren contracture?

Explanation

## Why "The pretendinous bands are most developed in the 4th and 5th rays, making them preferentially susceptible to myofibroblast proliferation and cord formation" is right Dupuytren contracture is a benign progressive fibroproliferative disease of the palmar aponeurosis characterized by myofibroblast proliferation and type III collagen deposition. The pathological process follows a predictable anatomical sequence: pretendinous band → natatory ligament → spiral band → lateral digital sheet. The ring and little fingers (4th and 5th rays) are affected first because their pretendinous bands are most developed and robust compared to the index and middle fingers. This anatomical predisposition explains the characteristic pattern of contracture seen in the clinical finding marked **C** (Maheshwari Orthopedics 10e, Bailey & Love 28e). ## Why each distractor is wrong - **"The intrinsic hand muscles of the ring and little fingers are inherently weaker and more prone to fibrotic degeneration"**: Dupuytren contracture is a disease of the palmar aponeurosis (fascia), not the intrinsic muscles. The contracture results from fascial cord formation, not muscular weakness or degeneration. - **"The palmar aponeurosis is thicker in the ulnar half of the palm, predisposing these digits to earlier contracture"**: While the ulnar digits may be affected more, the reason is not simply aponeurosis thickness. The specific anatomical development of the pretendinous bands is the key factor, not generalized thickness variation. - **"The spiral band and lateral digital sheet are exclusively present in the 4th and 5th rays, whereas other digits lack these fascial structures"**: This is incorrect. The spiral band and lateral digital sheet are present in all digits; the difference is that the pretendinous bands are most developed in the 4th and 5th rays, making them the initial site of pathological involvement. **High-Yield:** Dupuytren contracture preferentially affects ring and little fingers because their pretendinous bands are most developed; the disease progresses along a predictable fascial pathway (pretendinous band → natatory ligament → spiral band → lateral digital sheet). [cite:Maheshwari Orthopedics 10e / Bailey & Love 28e]