A cervical rib is an extra rib. It is attached to the last vertebra in the cervical spine (neck). Normally, the ribs start in the thoracic spine at T1. A cervical rib is considered a congenital anomaly meaning it's an abnormality present at birth.
Cervical ribs attach to the first thoracic rib with a dense band of fibrous tissue. Usually there is only one cervical rib and it's only on one side. Less often, there is a cervical rib on both sides.
The nerves and blood vessels that come down from the neck to the arm are called the neurovascular bundle. This bundle may rest on top of the cervical rib. In other people, the nerves pass through the ribs.
Pressure on the neurovascular bundle can cause a wide range of symptoms. Neck and/or arm pain are typical. Numbness and tingling in the arms and hands are also reported. Muscle fatigue and weakness is reported by some patients. Lifting the arms overhead causes increased pressure on the neurovascular bundle. In this position, the symptoms that are present at rest will be even more pronounced.