Why does cervical spondylosis cause numbness in the hands?

The hand has many sensory nerves which are interconnected with the cerebral cortex and the spinal cord and transmit sensory related information. When suffering from cervical spondylosis, the intervertebral discs or other structures of the cervical spine may compress the nerve roots which happen to innervate the sensory nerves in the hand, then irritation or sensory disturbance i.e. numbness in the hand may occur.