Spinal pain syndrome is a fast growing "pandemic" disease in highly civilised communities. Dealing with the etiopathogenesis of its most popular cause--spondylarthrosis--requires the knowledge of anatomy and physiology of the spine, and the explanation of biomechanic phenomena occurring in it. Many theories explaining the progress of spondylarthrosis are based on the assumption that the primary reason for pathology is degeneration of intervertebral discs, caused mainly by forced changes of spatial geometry of the spine; namely prolonged sitting or carrying weights in a bent position. The work presents Kapandji's hypothesis, attractive, among others, for its simplicity; explaining pathological mechanisms occurring within intervertebral disc. The hypothesis has also been advanced that the initiator of the process are degenerative changes in intervertebral joints, resulting from the so - called muscle dysbalance. They may occur earlier and only secondarily lead to disorders within the disc. The dynamics of progress of the disease varies, and the progression of pathological disorders is connected with the above - mentioned improper motor activity; first of all with the cumulation of effects of microtraumas, resulting from excessive sitting and bending, which may considerably accelerate this process, especially in patients genetically predisposed. In the work the progress of pathological process was presented from the stage of primary changes in nucleus pulposus to the phase of advanced adaptive--compensatory productive reactions in developed spondylosis.