Epiphyseal scar of the femoral head: a three-dimensional anatomic observation.

The purpose of this study was to inspect the three-dimensional structure of the epiphyseal scar of the femoral head. Three adult human femoral head specimens with a dense epiphyseal scar shown by radiography were used to study the morphology of the scar. One femoral head was cut in the coronal plane to show the cross-section. A trabecular pattern in the femoral head was demonstrated by radiography. The second femoral head specimen, was cut by a wafering saw in a plane parallel to the epiphyseal scar into 1.5 mm thick slices. Microradiographs of these specimen slices were taken to trace the scar from the proximal part of the femoral head to its distal end. In the third specimen, the epiphysis was chipped away to uncover the whole epiphyseal scar for a topographic examination by dissecting microscope and scanning electron microscope. The epiphyseal scar was found to consist of multiple layers of plate-like bony structure capping the metaphysis similar to an inverted cup with a defect adjacent to the fovea. Differences between the trabecular pattern in the epiphysis and metaphysis were distinctive. These morphologic characteristics of the femoral head should be taken into account when investigating stress distribution in the femoral head.