A Study on Variations of Nutrient Foramen of Humerus with its Clinical Implications.

Background Nutrient foramen is an opening into shaft of humerus which gives passage to the blood vessels of medullary cavity. The knowledge of nutrient foramen is important in surgical procedures like bone grafting and more recently in microsurgical vascularized bone transplantation. Objective To determine the number, location and direction of nutrient foramen and whether the nutrient foramens obey the rule of ossification, that is directed away from the growing end of the bone or not. Method The present study consisted of 253 (108 right and 145 left) dried humeri excluding any fracture or pathological abnormalities during the period of 15th December 2014 - 14th February 2015. Number and direction of nutrient foramen was observed in each humerus. Location of nutrient foramen in relation with surfaces and zones of humeri was determined. Result It has been observed that 60.87% of the humeri had a single nutrient foramen, 28.85% double foramen, 6.32% triple foramen and 1.98% of humeri had four nutrient foramina where as 1.98% humeri did not have any nutrient foramina. It was concluded that the majority (88.86%) of the nutrient foramina were present on the antero-medial surface, 6.52% on the anterolateral surface and 4.62% on the posterior surface of the shaft of humeri. It was also concluded that most (94.84%) of the foramina present in the zone II followed by zone III (4.62%) then by zone I (0.54%). All foramina were directed toward the lower end of humeri. Conclusion By knowing the number and location of the nutrient foramina in humerus would be useful in preventing intra-operative injury of nutrient artery during orthopedic, plastic and reconstructive surgery and will also be relevant in medico legal practice.