Stokes, Y.2006-06-192006-06-192003ANZIAM Journal, 2003; 44(4):561-5681446-18111446-8735http://hdl.handle.net/2440/309© Australian Mathematical Society 2003To assess rotational deformity in a broken forearm, an orthopaedic surgeon needs to determine the amount of rotation of the radius from one or more two-dimensional x-rays of the fracture. This requires only simple first-year university mathematics --- rotational transformations of ellipses plus a little differential calculus --- which yields a general formula giving the rotation angle from information obtained from an x-ray. Preliminary comparisons with experimental results are excellent. This is a practical problem that may be useful to motivate the teaching of conic sections.enJournal article002003065810.1017/S144618110001292X0001827616000052-s2.0-3374719254758684Stokes, Y. [0000-0003-0027-6077]