Musculo-skeletal   [back to the Category]

Upper Extremity Nerve Entrapment   [read the french version]

Author :   Errol Toran, D.C

This month's Case en Pointe involves the blood vessels and the nerves that pass near the shoulder. In the extreme ranges of motion these nerves can become entrapped and cause a variety of symptoms including skin eruptions and rashes, numbness and tingling in the fingers, pain down the arm and even chronic finger coldness.

The nerves that control the sensation and movement of the arms originate in the neck. They emerge from between the spinal bones and wind their way between the muscles of the neck to the front of the shoulder then down the arm to the fingers. The collar bone bridges the chest to the shoulder and provides stability. It also provides a vulnerable point where the nerves can become compressed and is called the Thoracic Outlet. The major and minor pectoral (chest muscles) in addition to other muscles and connective tissue fill the space between the chest and collar bone.

When the arm is in the various positions of port de bras the collar bone comes closer to the chest wall. Dancers tend to have greater flexibility, which allows the collar bone more movement. If the collar bone comes too close, the muscles and connective tissue will compress the nerves and blood vessels. When the arm is held out in second, the pectoralis muscles and the muscles of the neck tighten up. When you port de bras back and cambre, the space is maximally compressed. The contracted muscle swells as it gets pumped and it can become as hard as bone. The nerve getting caught beneath the collar bone is called Thoracic Outlet Syndrome.

The nerves are very sensitive structures. They often suffer minor trauma as they pass between the bones of the neck. The minor trauma will make the nerves increasingly sensitive. These sensitive nerves will be more susceptible to irritation by even minor compression at the thoracic outlet. Minor pressure can make the nerve less able to recover and repair. The dancer will see this as weakness in the hands and fingers or the arms will get tired quickly causing the muscles of the neck to grip (ginch). Many students have this correction day after day in class.

Treatment will include first determining how much nerve compression is occurring in the thoracic outlet or the neck. We then use electric stimulation to bring down the inflammation of the nerve. Massage is used to help keep the muscles soft and flexible. We will also mobilize the shoulder to help keep the collar bone freely mobile. Finally, we will define a strengthening and stabilizing program to prevent overuse stress and future injury.