Sensation
Pain is interceded by nociceptors, specialized peripheral tactile neurons that caution us to possibly harming stimuli at the skin by transducing these stimuli into electrical signals that are handed-off to higher brain centers (Basbaum et al., 2009). Nociceptors are pseudo-unipolar essential somatosensory neurons with their neuronal body situated in the DRG. They are bifurcate axons: the peripheral branch innervates the skin and the central branches synapse on second-order neurons in the dorsal horn of the spinal cord (Hunt et al., 2001).
The second-order neurons project to the mesencephalon and thalamus, which in turn associate with somatosensory and anterior cingulate cortices to manage tactile-discriminative and affective-cognitive features of pain, separetly. The spinal dorsal horn is a main site of combination of somatosensory data and is composed of several interneuron forming descending inhibitory and facilitatory pathways, able to modulate the transmission of nociceptive signals (Dubin et al., 2010).
If the noxious stimulus persists, processes of peripheral and central sensitization can occur, converting pain from acute to chronic. Central sensitization is
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They are compressible structures ready to circulate compressive loads through osmotic pressurization. In the IVD, the annulus fibrosus (AF), a concentric ring structure of sorted out lamellar collagen, encompasses the nucleus pulposus (NP). Discs are avascular in adulthood, except for the periphery. During childbirth, the human disc has some vascular supply but these vessels soon subside, leaving the disc with little direct blood supply in the healthy adult. Consequently, metabolic support a significant part of the IVD is dependent on the cartilaginous endplates adjacent to the vertebral body. A meningeal branch of the spinal nerve, also called the recurrent sinuvertebral nerve, innervates the region around the disc space (Grunhagen et al.,