Patients who present with neck pain along with arm numbness, pain, and/or weakness often ask, “…what’s causing this pain down my arm?” The condition can result from a bulging or herniated disk pinching a nerve in the neck. The cause of this complaint can be either a traumatic or non-traumatic event. In fact, sometimes, the patient has no idea what started their condition, as they cannot tie any specific event to the onset of symptoms.
The classic presentation includes neck pain that radiates into the arm in a specific area as each nerve affects different parts of the arm and hand. Describing the exact location of the arm complaint such as, “I have numbness in the arm and hand that makes my 4th and pinky fingers feel half asleep,” indicates the possibility of a pinched C8 nerve in the cervical region. This nerve can also be interfered with at the elbow and make the same two fingers numb. The difference between the two different conditions is when the nerve is pinched in the neck, the pain is located from the neck down the entire arm and into digits 4 and 5 of the hand. When this occurs at the elbow, the pain/numbness is located from the elbow down to the 4th and 5th digits, but no neck or upper arm pain exists.
Examination findings usually include limitations in certain cervical (neck) ranges of motion (ROMs)—usually in the direction that increases the pinch on the nerve. To determine where the nerve is pinched, there are a number of different compression tests that can recreate or increase the symptoms. Some compression tests include placing downward pressure on the head with the head pointing straight ahead, bent, or rotated to each side. Other compression tests are performed by pressing in areas where the nerve travels such as in the lower front aspect of the neck, in the front of the shoulder where the arm connects to the chest/trunk, at the elbow, and at the wrist. If there is a pinched nerve, then numbness, tingling, and/or pain will be reproduced when pressure is applied to these regions. Other tests include checking reflexes and muscle strength in the arm. When a nerve is pinched, the reflexes will be sluggish or absent and certain movements in the arm are weak when compared to the opposite side.
Another very practical test is called the cervical (neck) distraction test where a traction force is applied to the neck. When neck and/or arm pain is reduced, this means there is a pinched nerve. This test is particularly useful because when pain is reduced, the test supports the need for a treatment approach called cervical traction. In a study that examined the use of cervical traction (applied for 15 minutes, 3x/day at 8-12 pounds), 78% of 81 patients reported a significant improvement in symptoms, which is very effective. Other forms of care that can be highly effective include spinal manipulation, spinal mobilization, certain exercises, and physical therapy modalities.