Bending forces can cause a child’s bone to crease on the compression (concave) side of the bend, leaving the tension cortex (convex) intact, but slightly bent.
This is known as a torus or buckle fracture. A torus is a doughnut-shaped mathematical figure.
This injury is usually caused by a fall onto an outstretched hand.
The injury is associated with local tenderness over the distal forearm or specifically over the distal radius. Local swelling may be present but can be difficult to detect. There is usually no discernible deformity.
A torus fracture is inherently stable (provided the tension cortex is unbroken), will usually model out any angulation over time, and usually requires only simple splintage.
X-ray will demonstrate a compression failure of the posterior cortex of the radius.
If the tension cortex breaks, however, the fracture is inherently unstable and progressive angulation is to be expected. Such fractures may be called greenstick fractures.
Reduction and three-point molding of a suitable cast are necessary.