Human anterior and posterior cervical longitudinal ligaments possess similar tensile properties

One hundred bone-ligament-bone complexes were isolated from the cervical spines of 20 fresh-frozen human cadavers and mechanically tested in uniaxial tension. Load-elongation curves representing the structural properties of the complex were obtained, and stiffness, ultimate load, energy at failure, and elongation were determined from the curves. Stress-strain curves representing the mechanical properties of the ligament substance were also obtained, and elastic modulus was determined from these curves. Comparisons were made between anterior and posterior longitudinal ligaments and among cervical levels. The cross-sectional area of the anterior ligament was smaller at the C2-C3 level than at subaxial levels. There was a trend toward less stiffness but more energy at failure and greater elastic modulus for the anterior compared with the posterior ligaments at subaxial levels, although the differences were not statistically significant (p > 0.05).