Two challenging elements to this case worthy of remark: 1) Despite encountering a circular canal orifice (as opposed to an ovoid orifice) an unexpected deep apical split was encountered in the distal root. 2) A 90 degree short radius curvature is present in apical third of mesial root. The apical 1.5- 2 mm were instrumented only with a size 10 k file. Rotary files or larger size k files were not a viable option in this portion of the canal.