Anatomical variability of the sural nerve in South Indian population: A foetal study

Sural nerve (SN) is clinically important and is employed in nerve conduction studies, nerve biopsies and also used for nerve grafting. Therefore the anatomical variations of the sural nerve are imperative. SN is formed by either continuation of medial sural cutaneous nerve (MSCN) or by joining with peroneal communicating branch (PCB) of common peroneal nerve. It innervates the posterolateral region of leg and dorsolateral aspect of the foot. Various studies have been carried out worldwide to study the anatomical variations of the sural nerve in adults and fetus alike; however there is a dearth in the literature from India in this regard. Further the percentage of variability does change in different populations. Therefore to study the variability of the sural nerve in the leg in fetuses, 13 full term formalin fixed foetuses were dissected to expose the sural nerve. The sural nerve was classified into three types based on its formation Type A-Formation of SN by the union of MSCN and PCB; Type B-SN as continuation of MSCN; Type C-SN as continuation of PCB. The level of formation of the nerve was also identified with relation to the leg. Based on the variability in the formation of the SN, 23 out of 26 limbs (88.46%) were included under type A, two under type B (7.69%). Type C was noted in a single case (3.85%). The level of formation of the SN in the leg was at the upper one-third in three cases, middle one-third in five cases and lower one-third in the remaining 18 cases. The current study is an attempt to present the variations in the anatomy of the SN, the knowledge of which is essential as the SN is important clinically.