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Updated: May 2, 2026
In Vivo Electrophysiological Measurements on Mouse Sciatic Nerves
Published on: April 13, 2014
Misinterpretation of sural nerve conduction studies due to anatomical variation
Hatice Tankisi1, Kirsten Pugdahl1, Marit Otto1
1Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
Objective:
Anatomical variation of the sural nerve has been documented in numerous cadaver studies. The sural nerve conduction parameters can potentially be influenced by the sural nerve type A formation formed by the union of the medial sural cutaneous nerve (MSCN) and the peroneal communicating branch (PCB) and the type C formation with the sural nerve formed solely by the PCB.
Methods:
In 17 out of 240 prospectively examined subjects referred for polyneuropathy a suspicion of an anatomical variation of the sural nerve was raised due to decreased amplitude or substantial side-to-side variation (>50%) of the sensory nerve action potential (SNAP) in disproportion to the clinical findings. To verify the variation the sural nerve was examined further with surface electrodes and near-nerve technique, including extra lateral and distal needle placements.
Results:
In all 17 subjects an anatomical variation affecting the sural SNAP was confirmed as a normal sural SNAP could be obtained by changing the electrode placement. The most frequent variation, seen in 15 subjects, was a type A formation with union of the MSCN and the PCB distally at low calf, while a type C formation was seen in 2 subjects.
Conclusions:
In case of a decreased sural SNAP amplitude or substantial side-to-side variation in disproportion to the neurologic evaluation, an anatomical variation instead of pathology could be suspected and a different electrode placement be considered.
Significance:
Neurophysiologists should be aware of different types of formations of the sural nerve which may cause misinterpretations of nerve conduction studies, especially when needle electrodes are used.
