Anatomical Variations in the Course and Level of Termination of Superficial Peroneal Nerve- A Cadaveric Study

Abstract

Introduction: Several variations in the course and branching pattern of the Superficial Peroneal Nerve (SPN) have been reported. Knowledge of the different course of SPN is essential in reducing the risk of iatrogenic injury during the orthopaedic foot and ankle surgery and various other procedures. Aim: To observe any variations in the course, and level of termination of SPN. Materials and Methods: This descriptive analytical study was conducted on 50 lower limb specimens in the Department of Anatomy, Bangalore Medical College and Research Institute Bengaluru from January 2013 to January 2016. Dissection kit was used for dissection, digital camera was used for photography of specimens, measuring tape was used to measure the distance at which the SPN became cutaneous with respect to the tip of lateral malleolus and the distance at which SPN terminated into medial and Intermediate Dorsal Cutaneous Nerve (IDCN) with reference to the tip of lateral malleolus. Descriptive statistics was used and results were expressed as Mean±SD. Results: It was observed that the distance at which SPN became cutaneous with respect to tip of lateral malleolus was 10±2.82 cm. The level of termination of SPN into Medial Dorsal Cutaneous Nerve (MDCN) and IDCN with reference to tip of lateral malleolus was 4.7±2.08 cm. In 5 (10%) of 50 specimens the SPN terminated at a higher level before piercing the deep fascia. Out of these 5 specimens, it was observed that in one specimen the SPN terminated above the head of fibula before piercing Peroneus Longus (PL) muscle. In another specimen, the SPN terminated near the head of fibula before piercing PL muscle. In one of the specimens SPN terminated near head of fibula after piercing PL, in two specimens SPN terminated in upper third of the leg after piercing PL muscle and their terminal branches pierced the deep fascia and emerged out at different level with respect to tip of lateral malleolus. Conclusion: SPN became cutaneous and terminated in the distal third of the leg in most cases. This knowledge is very helpful to surgeons and orthopaedists in performing fasciotomy, and ankle arthroscopy to prevent iatrogenic injury to the nerve.