BIOMECHANICAL PROPERTIES OF THE HUMAN TIBIA - FRACTURE-BEHAVIOR AND MORPHOLOGY

Standardized biomechanical dynamic load tests were performed to obtain fundamental information on the fracture behavior and morphology of th e human tibia. After preparation, the specimens (n=32) were loaded to breakage by ventral (one side alternately), dorsal, medial or lateral loading on a servo-hydraulic testing machine (Waiter und Bai, Lohninge n, Switzerland). Primary and secondary fracture lines and fissures wer e marked differently on the three surfaces of the tibia specimens. The y were then videoscanned and digitized on a flatbed scanner to give tw o-dimensional fracture-line images. Load limits were 2475 to 12 206 Ne wton. The study revealed both direct fracture patterns with the fractu re lines originating from the opposite site of impact, and indirect fr acture patterns originating from the distal third of the specimens. Di rect fractures occurred in 46% of the specimens after ventral loading, in 80% after medial or lateral loading, and in 100% after dorsal load ing. Ventral, medial or lateral loading frequently produced direct wed ge fractures of the Messerer type. Dorsal loading resulted in differen t direct patterns characterized by transverse fractures with longitudi nal fissures at the impact site of the loading stamp. Direct transvers e fractures also often showed a wedge-shaped pattern due to additional fissures. These were, however, identifiable only after maceration of the specimens and should receive closer attention in forensic practice .