Spondylosis is the degeneration of the vertebral column from any cause. In the more narrow sense it refers to spinal osteoarthritis, the age-related degeneration of the spinal column, which is the most common cause of spondylosis. The degenerative process in osteoarthritis chiefly affects the vertebral bodies, the neural foramina and the facet joints (facet syndrome). If severe, it may cause pressure on the spinal cord or nerve roots with subsequent sensory or motor disturbances, such as pain, paresthesia, imbalance, and muscle weakness in the limbs.
When the space between two adjacent vertebrae narrows, compression of a nerve root emerging from the spinal cord may result in radiculopathy (sensory and motor disturbances, such as severe pain in the neck, shoulder, arm, back, or leg, accompanied by muscle weakness). Less commonly, direct pressure on the spinal cord (typically in the cervical spine) may result in myelopathy, characterized by global weakness, gait dysfunction, loss of balance, and loss of bowel or bladder control. The patient may experience shocks (paresthesia) in hands and legs because of nerve compression and lack of blood flow. If vertebrae of the neck are involved it is labelled cervical spondylosis. Lower back spondylosis is labeled lumbar spondylosis. The term is from Ancient Greek σπόνδυλος spóndylos, "a vertebra", in plural "vertebrae – the backbone".
In cervical spondylosis, a patient may be presented with dull neck pain with neck stiffness in the initial stages of the disease. As the disease progresses, symptoms related to radiculopathy (due to compression of exiting spinal nerve by narrowed intervertebral foramen) or myelopathy (due to compression on the spinal cord) can occur. Reduced range of motion of the neck is the most frequent objective finding on physical examination.
In cervical radiculopathy, there would be numbness, tingling, or burning pain at the skin area supplied by the spinal nerve, shooting pain along the course of the spinal nerve, or weakness or absent tendon reflex of the muscle supplied by the nerve.