Ultrasound imaging of the tibial and common fibular nerves in the popliteal fossa during lower extremity limb movements

The direction and magnitude of nerve mobility in the lower extremity has been quantified in fixed cadaveric tissue but extrapolation of findings to live humans is limited. Ultrasound is an emerging tool for in vivo imaging of soft tissues such as peripheral nerve. The purpose of this study was to investigate in vivo excursion of the tibial and common fibular nerves in the popliteal fossa during limb positioning in healthy participants. Methods: Real time ultrasound imaging of the tibial and common fibular nerves in the popliteal fossa was performed on 5 healthy subjects using a Siemens Acuson Sequoia machine. Imaging was performed while the ankle was moved through plantar and dorsiflexion in two hip positions. Results: The tibial nerve glided proximal, deep and lateral during plantar flexion and distal, superficial and medial during dorsiflexion. The common fibular nerve glided superficial and lateral during plantar flexion and deep and medial during dorsiflexion. Conclusions: The tibial and common fibular nerves have significant mobility in both the transverse and sagittal planes during ankle motion. The direction of proximal and distal excursion of the tibial nerve is consistent with previous cadaveric studies. Ultrasound imaging is an effective, non‐invasive way to investigate movement of the large peripheral nerves in the lower extremity.