Background
Knowledge regarding nutrient foramina of bones is useful in surgical procedures such as microvascular bone transfer in order to preserve the circulation. The objective of the present study was to study the morphology and topography of nutrient foramina and to determine the foraminal index of the lower limb long bones to provide detailed data on such features.

Method 
The study comprised examination of 206 lower limb long bones which included femora, tibiae and fibulae. The nutrient foramina were identified analysed macroscopically and the foramen index calculated. Each bone was divided into five parts and topographical analysis was performed on each section.

Results
Femora had single nutrient foramen in 47.7% of the cases, double foramen in 44.2% of the cases, triple in 3.5% of the cases and an absence of foramen in 4.6%. In the case of tibiae, 98.6% showed single foramen and in 1.4% of the cases, the foramen was absent. With respect to fibulae, 90.2% had single foramen and foramen was absent in 9.8%. The mean foraminal index was 38.9 for the femora, 32.5 for tibiae and 49.2 for fibulae. The majority (51.3%) of the foramina in the femora were located at the 2/5th part, 98.3% of the tibiae foramina at the 2/5th part and 60% of the fibulae at the 3/5th part.

Conclusion
The study provides information on the morphology and topography of nutrient foramina in lower limb long bones. The double foramina were more common in femur and rare in the tibia and fibula. The foramina of the femur and tibia were commonly observed at their upper part, whereas in the fibula they were present on the lower part. This knowledge of the nutrient foramina has to be kept in mind during surgical procedures.