1. Eleven pelves and lumbar spines (eight embalmed and three unembalmed) were tested under static vertical loading; five specimens of the sacrum and the lumbar spines and five to eight thoracic vertebrae and discs (two embalmed, three unembalmed) were tested by static anterior bending; and four specimens of the sacrum and lumbar vertebrae and discs (all embalmed) were tested by static lateral bending.
2. Embalming increased the average maximum load and energy absorbed during vertical loading but decreased time magnitude of the average deflection.
3. Specimens tested by anterior bending had a greater bending moment, regardless of the condition of the specimen (embalmed or unembalmed) than those tested by lateral bending.
4. Embalmed specimens tested by lateral bending had a greater average deflection than similar specimens tested by anterior bending.
5. The greatest average amount of energy (inch pounds) was absorbed during vertical loading and the least during lateral bending. Embalming increases the energy-absorbing capacity of the pelvis and lumbar spine during vertical loading.
6. Unembalmed specimens tested by anterior bending showed the greatest average deflection.
7. Among the embalmed specimens the load increased more rapidly than the deflection in most of the specimens tested by vertical loading and in all of the specimens tested by anterior bending. In embalmed specimens tested by lateral bending the load increased more rapidly than deflection at first but later leveled off.
8. The slope of the load-deflection curve was generally steeper for specimens tested by vertical loading than for those tested by anterior or lateral bending. The slope of the curves for embalmed specimens was usually steeper than those for unembalmed ones.
9. No apparent relationship was found between the age of the individual whose spine was tested and the various biomechanical phenomena studied.
Department of Anatomy, College of Medicine, and the Department of Engineering Mechanics, College of Engineering, Wayne State University, Detroit