Fascicular anatomy of human femoral nerve: implications for neural prostheses using nerve cuff electrodes.

Clinical interventions to restore standing or stepping by using nerve cuff stimulation require a detailed knowledge of femoral nerve neuroanatomy. We harvested eight femoral nerves with all distal branches and characterized the branching patterns and diameters. The fascicular representation of each distal nerve was identified and traced proximally to create fascicle maps of the compound femoral nerve in four cadaver specimens. Distal nerves were consistently represented as individual fascicles or distinct groups of fascicles in the compound femoral nerve. Branch-free length of the compound femoral nerve was 1.50 +/- 0.47 cm (mean +/- standard deviation). Compound femoral nerve cross sections were noncircular with major and minor diameters of 10.50 +/- 1.52 mm and 2.30 +/- 0.63 mm, respectively. In vivo intraoperative measurements in six subjects were consistent with cadaver results. Selective stimulation of individual muscles innervated by the femoral nerve may therefore be possible with a single neural prosthesis able to selectively stimulate individual groups of fascicles.