Diaphysial nutrient foramina in human metacarpals and metatarsals.

728 metacarpals and 691 metatarsals of unknown sex, and 120 metacarpals and metatarsals, each of known sex, were studied for the number, position, direction and symmetry of the diaphysial nutrient foramina. It was found that, in general, these bones had one nutrient foramen which was situated in the middle third of the shaft (over 90%). Few bones had no foramina and some had two. In the first and second metacarpals the foramina were mostly situated on the medial surface, and in the other metacarpals mostly on the lateral surface; whereas in the first three metatarsals the foramina were mostly situated on the lateral surface and in the remaining metatarsals mostly on the medial surface. There was a good deal of bilateral symmetry in the foramina. Without any exception, the foramina were directed away from the growing end. The various theories put forward to account for the direction of the nutrient foramina have been considered. The findings favour the 'growing-end' theory.