Isometric exercises for the cervical spine are recommended by many doctors to gently strengthen the deep stabilizing muscles.
Isometric training means that muscles are contracted without changing their length. There is no movement in the area of training, however, the muscle itself is contracted through pushing or pulling (for example against a wall). Only a change of muscle tension occurs. A couple of different physical therapies use this technique.
Commonly, only the own body weight is used to exercise. For example, you might train the pectoral muscle by pushing your hands together in front of your chest.
Some advantages of isometric exercises could be:
You don’t need much time to perform those exercises;
You don’t need any other things, such as weights. Only your own body has to be present;
You can vary between different levels of exercise depending on your individual needs;
Even bed-bound patients might do them.
One exercise I perform to stabilize my cervical spine is the following:
I push my head against my open hand, which is placed above my ear and hold it for five seconds. Then I change to the opposite side (right -> left); then to the front and to the back.