The lumbosacral (LS) spine region in birds shows unique modifications: a high-density glycogen body, wedged between both spinal cord hemispheres, supported by a accentuated denticulate ligament network, accessory lobes, surrounded by spinal fluid inside an expanded canal with semicircular grooves. Evidence for mechanosensing capabilities of accessory lobes indicates a ‘lumbosacral organ’. Previous hypotheses considered intraspinal sensing of fluid-flow, pressure, or strain. Based on our own observations of potential for soft tissue movement inside the LS region (Kamska et al, in review), we consider the option of strain-based sensing caused by tissue deformation. Body movements would accelerate LS soft tissue, causing elastic deformations sensed by accessory lobes. Due to insufficient access to the LS soft tissues in vivo, we are now implementing a mechanical simulator to study the putative LS mechanosensing function. Based on the morphology of quails we developed an LS phantom. It contains the spinal cord’s simplified stand-ins; spinal fluid, glycogen body, spinal canal, and spinal cord with denticulate ligaments. A mechanism moves the LS phantom, similar to movements caused by legged locomotion, and a camera records the resulting soft tissue oscillations. This model will allows us to characterize the potential for physical interactions between the LS soft tissue and bony canal, to understand the sensitivity characteristics of the putative LS sensing organ.