The common peroneal nerve is extremely vulnerable to injury as it winds around the neck of the fibula. At this site, it is exposed to direct trauma or is involved in fractures of the upper pa of the fibula. While passing behind the head of the fibula, it winds laterally around the neck of the bone, pierces peroneus longus muscle, and divides into two terminal branches: the superficial peroneal nerve and deep peroneal nerve (anterior tibial nerve). Injury to common peroneal nerve causes foot drop.Ref: Clinical Anatomy By Regions By Richard S. Snell, 9th edition, Page 485.