Nutrient arteries, the main blood supply to long bones, are particularly important during the active growth period, as well as during the early phases of ossification. In the present study, 569 adult human long bones of the upper (101 humeri, 93 radii, 102 ulnae) and lower (100 femora, 100 tibiae, 73 fibulae) limbs were investigated to determine the number and location of their nutrient foramina. For each bone, a foraminal index was calculated giving the Location of the nutrient foramen in relation to its proximal end. In the upper limb, foramina were Located on the diaphysis 15-69% of the overall length of the humerus, 22-46% for the radius and 27-54% for the ulna. In the tower limb, foramina were located on the diaphysis 29-69% of the overall length of the femur, 27-63% for the tibia and 26-83% for the fibula. In addition, the number and the distribution of the foramina in relation to specific regions/surfaces of the diaphysis were identified. This study provides additional and important information on the location and number of nutrient foramina in the long bones of the upper and lower limbs in the Turkish Caucasian population. (c) 2006 Elsevier GmbH. All rights reserved.