Table 2.

The unloaded excised intervertebral angles were measured directly from a tracing of the X-radiograph shown in Fig. 2 as the angles between lines drawn parallel to the long axes of adjacent vertebral centra (Gal, 1993a)

JointUnloaded angle (degrees)Loaded angle (degrees)Δθiv (degrees)
L1L2+6-4-10
L2L3+3-4-7
L3L4+4-4-8
L4L5+3-4-7
L5L6+7-4-11
Mean Δθiv-8.6 (≈-9)
  • The loaded in vivo angles were estimated from the external dorsal curve of the `groomer' animal shown in Fig. 1 (and explained in detail in the methodology text).

    Δθiv per joint was taken as the difference between the loaded angular position (flexed) and the unloaded (hyper-extended) position.