Error regarding when back pain occurs with nerve root compression. The article “Diagnosis and Treatment of Peripheral Arterial Disease” (September 1, 2013, p. 306) contained an error in Table 1 (p. 307). In the second column, second row under the “Neurologic” heading (nerve root compression), it said, “Posterior radiating pain originating in the back, often changing with position and improving with lumbar flexion.” This should have said, “Posterior radiating pain originating in the back, often changing with position and improving with lumbar extension.” The online version of this article has been corrected.