Honda sign (sacrum)
Sacral insufficiency fractures are usually vertically through the sacral ala, paralleling the sacroiliac joint, often with a transverse component - this pattern resembles the capital letter H, leading to the designation of Honda sign / H sign / H pattern.
With the more common availability of MRI, radioisotope scans (technetium 99m HDP) are less commonly undertaken.
History and etymology
The name derives from the appearance of the Honda car manufacturers insignia (badge), with the H-shaped appearance representing the areas of increased radioisotope uptake in the sacral ala medial to the sacroiliac joints with a band connecting the bilateral areas of vertical uptake.