Factors Influencing Common Fibular Nerve Course Variability before Bifurcation into the Superficial Fibular Nerve and Deep Fibular Nerve: A Cadaveric Study

Background and Objectives: The common fibular nerve (CFN) has anatomical variance between individuals as it transitions from the posterior thigh to the anterior leg. The nerve’s course around the fibular neck is of particular interest, where it becomes vulnerable to injury at the lateral knee. Therefore, we sought to compare factors that may predict distal CFN variability, such as height, age, sex, fibular length, and proximal sciatic variations, which individually or cumulatively play a role in predicting clinically significant locations where the CFN commonly transitions among certain populations. Methods: In this cadaveric study, twenty anatomically-fixed specimens were analyzed, ten males and ten females. Data gathered included age, sex, height, CFN transition point measured from the proximal head of the fibular to the point 90 degrees off the midline of the fibula where the CFN courses around the fibular neck, fibular length, and proximal sciatic nerve variations characterized based on the Beaton and Anson classification system. Factors were compared and statistical values were generated. Results: There was a statistically significant difference between CFN transition points compared to fibular lengths, heights, and between sexes. Sciatic nerve (SN) bifurcation levels and exits were bilaterally identical on all cadavers. All SN exits were Beaton and Anson type 1 (undivided nerve below and undivided piriformis), and bifurcation levels were 20% high, 25% middle, and 55% low. Conclusions: This study highlights the importance of considering a person’s height, fibular length, and sex when addressing injuries involving the CFN at the lateral leg.