The magnitude, direction and abruptness of a force on the spine affect whether it will cause pathology. With regard to abruptness, sufficient muscle resistance (contracture) can prevent injury. Chiropractic manipulation and IDD decompression involves the application of forces upon the spine and specifically with instructions to the patient not to exert the requisite muscle resistance prior to and during the exertion of the force. If the magnitude of the force is too great, if there is sufficient torque, if the force is applied too quickly, and/or without sufficient resistance, the fibrotic ring holding the disc material can tear. Normal spinal cord function is essential for having normal extremity strength, the ability to walk, sense, and balance oneself. Compression of the cord and/or rootlets can result weakening, sensory abnormalities, pain, balance difficulties and awkwardness, postural issues, and motor skills deficits. In order for the brain, spinal cord, and peripheral nervous system to function normally, there cannot be any significant pressure exerted on it. Impinging herniated disc material can result in pathology manifesting.
Chiropractic disc damage medical expert witness specialties include neurosurgery, orthopaedic spine surgery, and vascular neurology.