Potential pitfalls of nerve conduction studies (NCSs) may be classified into: physiologic factors; distance measurement errors; unrecognized anomalous innervation; stimulation errors and recording errors. Temperature and age are comes under physiologic factors. Low temperatures increase the distal motor latency and F wave latency, and they reduce sensory and motor nerve conduction velocities. The sensory nerve action potential (SNAP) is a compound nerve action potential or a summation of many different individual SNAPs. Submaximal stimulation of the sensory nerve should give rise to a small potential. One of the common technical problems in sensory NCS is the presence of stimulus artifact, which can obscure a normal SNAP. When performing motor NCSs, it is not uncommon to see a significant reduction in the amplitude of the compound muscle action potential (CMAP) between the distal and proximal sites of stimulation. Martin-Gruber anastomosis (MGA) is a relatively common anomalous innervation of intrinsic hand muscles.