May 15, 2005
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Head and Neck
by Anne Kosacheff, Physical Therapist
This month the subject is the head and neck. We will review the basic anatomy, including bones (timemta enri), cervical vertebrae (uyaqinrat), ligaments, tendons and muscles (yualuq). Next month we will also include a general overview of common injuries, and some easy stretches to try if you are having troubles with your neck.
Cervical Vertebrae and Nerves
There are two very important joints at the top of your neck. The Occipital-Atlas (OA) joint and the Atlas-Axis (AA) joint. The OA joint is the joint between the skull (the occipital bone) and the first cervical vertebrae (C1- the Atlas). The AA joint is the joint between the Atlas and the Axis (the second cervical vertebrae- C2). There are many, many small muscles, tendons and ligaments in this area holding the bones together. The majority of your motion turning your head left and right occurs in this small area. Any decrease in flexibility of the soft tissues here can cause decreased motion, headaches, and in severe cases can cause dizziness, nausea, or other symptoms related to involvement of the cranial nerves (nerves originating in the area ABOVE the first cervical vertebrae).
The AA joint is different than the remainder of the cervical spine. Part of the axis sticks straight up in the front of the spine. This is called the odontoid process. It is important in that it keeps the axis in place, and protects the spinal cord from damage. Any damage to the axis or atlas is life threatening, as any damage to the upper spinal cord will affect the nerves that regulate breathing and other autonomic functions of the body.
The remaining five cervical vertebrae (C3, C4, C5, C6 and C7) are stacked upon each other with discs between each vertebral body. (Do you remember what the discs are made of? Do you remember what they do?) A nerve exits the spinal cord above each cervical vertebra. Basically, the nerves exiting above the top five vertebrae innervate the muscles of the top of the neck. The nerves from C5 through T1 (the first thoracic vertebrae) come together to form the brachial plexus. This plexus ("a network of interlacing nerves") travels from the neck, behind the collarbone and pectoral muscle (in the front of your shoulder), across the shoulder joint and into the arm. The nerves terminate in the muscles and skin of the arm and hand. Most nerves have a sensory component (they carry sensation from the skin to the spinal cord) and a motor component (they carry signals from the spinal cord to the muscles).
Any nerve can be injured or pinched at any point along its path. Sometimes it is a disc that is pushing out into the foramen (opening) in the vertebral column that pinches the nerve. Sometimes it is a muscle in the neck that is tight, and pinches the nerve. Sometimes it is a muscle or tendon in the arm or hand that pinches the nerve. Being aware of specific patterns of symptoms, whether the symptoms are worse in the morning or evening, at rest or with activity, will help your medical providers determine where the problem is.
Cervical Spine Muscles
There is a large muscle in the front of your neck called the platysma. It starts along your chin and lower jaw, and spreads across the front of your neck and ends on your collarbones. If you try to pull the corners of your mouth toward your shoulders, you will activate the platysma.
Under the platysma are many muscles in the front of your spine. All the "tubes" in your throat (the esophagus and trachea), and the hyoid bone are held in place by muscles. Hunching forward at your computer station, or over a carving/knitting project can cause these muscles to shorten. A slouched posture can also cause these muscles to shorten. Shortened muscles in the front of your neck can cause pain in the muscles in the back of your neck. Remember to stretch the front of your neck early and often!
In the back of your neck, next to the spinous processes of the vertebrae (the bones you can feel along the midline of the spine), you can feel twin columns of muscle. These are called your erector spinae, or paraspinals. Along the sides of the neck are the scalenes, and overlying the back of the scalenes and the paraspinals are the upper trapezius. The upper trapezius and scalenes connect your neck to your shoulders, and can be injured when you lift or pull items that are heavier than expected, and can be damaged with overuse activities.
The scalene muscles are important to consider in that the brachial plexus runs through the muscles. If the scalenes are tight, they can pinch the nerves, and cause symptoms into the shoulder, arm or hand.
Next month, look for more pictures and some easy stretches to keep your neck healthy and flexible!