• Ianuzzi A
• Pickar JG
• Khalsa PS

• Biomechanical Phenomena
• Cats
• Lumbar Vertebrae / physiology
• Models, Animal
• Proprioception
• Stress, Mechanical
• Zygapophyseal Joint / physiology

Methods: Cat lumbar spine specimens were tested during extension, flexion, and lateral bending. Joint kinematics and FJC principal strain were measured optically. Facet joint capsule strain–intervertebral angle (IVA) regression relationships were established for the 3 most caudal lumbar joints using cat (current study) and human (prior study) data. The FJC strain–IVA relationships were used to estimate cat and human spine kinematics that corresponded to published sensory neuron response thresholds (5% and 10% strain) for low-threshold mechanoreceptors.

Results: Significant linear relationships between IVA and strain were observed for both human and cat during motions that produced tension in the FJCs (P < .01). During motions that produced tension in the FJCs, the models predicted that FJC strain magnitudes corresponding to published sensory neuron response thresholds would be produced by IVA magnitudes within the physiological range of lumbar motion.

Conclusions: Data from the current study support the proprioceptive role of lumbar spine FJC and low-threshold mechanoreceptive afferents and can be used in interpreting combined neurophysiological and biomechanical studies of cat lumbar spines.

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