Jackstone calculus is the name assigned to the appearance of a subset of urinary calculi.
Jackstone calculi are almost always composed of calcium oxalate dihydrate. They are nearly always created, and thus, located, in the bladder rather than the upper urinary tract.
They are composed of a loose crystalline lattice of calcium oxalate dihydrate. This renders them more susceptible to fragmentation with various forms of lithotripsy, though the downside is that lithotripsy is less efficacious for bladder stones 2.
These calculi have spiculated edges that resemble the appearance of toy jacks, hence the name.
- 1. Singh KJ, Tiwari A, Goyal A. Jackstone: A rare entity of vesical calculus. Indian J Urol. 2011;27 (4): 543-4. doi:10.4103/0970-1591.91449 - Free text at pubmed - Pubmed citation
- 2. Dyer RB, Chen MY, Zagoria RJ. Classic signs in uroradiology. Radiographics. 2004;24 Suppl 1 (suppl 1): S247-80. Radiographics (full text) - doi:10.1148/rg.24si045509 - Pubmed citation