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 is often caused from a bulging or herniated disk pinching a nerve in the neck. The cause of this complaint can include both trauma as well as non-traumatic events. In fact, sometimes, the patient has no idea what started their condition, as they cannot tie any specific event to the onset.
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,” tells us that you have a pinched C8 nerve. This nerve can also be pinched 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 & 5 of the hand. When the nerve is pinched at the elbow, the pain/numbness is located from the elbow down to the 4th & 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. Another common finding is the arm is often held over the head because there is more stretching on the nerve when the arm is hanging down and pain in the neck and arm increases. Hence, raising the arm over the head reduces the neck/arm pain. 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, numbness, tingling and/or pain will be reproduced when pressure is applied to these regions. Other tests include testing 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. It has been reported that the use of cervical traction when applied 3x/day for 15 minutes each, 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, physical therapy modalities, and certain medications.