Hide-bound appearance | Radiology Signs

The hide-bound appearance of the small bowel on barium imaging is caused by intestinal involvement in systemic sclerosis (scleroderma). It results from asymmetric atrophy of the small bowel’s smooth muscle, specifically a greater loss of the inner circular muscle layer compared to the outer longitudinal layer. This leads to contraction of the longitudinal muscle fibers, foreshortening of the small bowel, and close packing of the valvulae conniventes (mucosal folds), producing narrow separation of these folds despite bowel dilatation. Clinically, this sign is associated with scleroderma, a multisystem connective tissue disease characterized by fibrosis and vascular abnormalities affecting skin and internal organs, including the gastrointestinal tract.

Why is it called so?

The term “hide-bound” was coined by Horowitz and Meyers in 1973 and originally refers to the appearance of emaciated cattle whose skin is tightly bound to the underlying tissue, reflecting the tightly packed, contracted small bowel folds observed radiologically in scleroderma.

Pathophysiology

In scleroderma, fibrotic replacement leads to selective smooth muscle atrophy, with disproportionate loss of the inner circular muscularis layer relative to the outer longitudinal layer. The preserved contraction of the longitudinal layer shortens the bowel, causing the valvulae conniventes to space closely and appear compressed. Despite dilation of the bowel lumen due to atony, the folds remain narrow and tightly packed, creating the characteristic radiologic “hide-bound appearance.”

Alternative names: None

Other associated named signs: None