You can feel and see the muscle that is most prominent at the front of the neck. This is the sternocleidomastoid muscle. This muscle is usually in pain after an auto accident when stretching occurs to this muscle as the head and moves backward and forward. The head can be abnormally tilted to one side due to spasm. For example, if the right sternocleidomastoid muscle is in spasm, the face and chin will be turned to the left. This is known as torticollis.
The trapezius muscle is at the back of the neck. This muscle gives the contour to form the slope of the shoulder. It stretches from the base of the head to the tip of the shoulder. The upper portion of the trapezius is commonly very tender in most people. If one side is more in spasm, you can see the swelling very clearly from the front.
The neck movements include looking down (flexion), looking up (extension), neck rotation and bending or inclining the neck sideways (lateral flexion).
The normal range of motion of the neck: At least 50% of flexion and extension occurs between the occiput of the skull bone and C1 vertebra. This is called the "yes" joint as in nodding the head to agree. The remaining 50% is distributed between the movements occurring between C2-C7 levels. Most of the movements occur at the C5 and C6 vertebral levels.
In the normal situation, you should be able to bend your neck down so that you should be able to touch your chin to your chest.
You should be able to bend your neck upward such that you should be able to directly look at the ceiling above you. All these movements should be able to done without hesitation or halting movements. You must not lean back to perform this motion.
When you rotate the neck as in saying "no" at least 50% of the rotation movements between the C1 and C2 levels which is thus known as the "no" joint. The remaining 50% of the rotation movements occur between C3 to C7. In the normal situation, you should be able to turn your head in such a way that your chin is in line with the shoulder, almost touching the shoulder. You must be careful not to elevate your shoulder to perform this motion.
Bending or inclining the neck sideways, involve all the cervical vertebrae. To perform this motion, the neck has to also rotate. Normally, you should be able to incline the neck sideways for about 45 ° from the midline of the head from the starting point which should be a plane perpendicular to the floor. When you have restriction to perform this motion, you will usually have a tendency to elevate the shoulder.
Difficulties with neck range of motion can occur with fixed deformities from having arthritis in the neck. However, pain and / or discomfort with tightness of the muscles will further restrict the range of motion. Relaxing the muscles of the head and neck is essential to regain the loss in range of motion due to pain and spasm of these muscles.