Carpal tunnel syndrome is a condition in which the median nerve becomes irritated or compressed in the carpal tunnel of the wrist. The median nerve supplies the thumb, index finger, middle finger, and radial half of the ring finger (side closest to the thumb). The carpal tunnel houses 9 flexor tendons and the median nerve at the base of the palm. Carpal (wrist) bones surround the tunnel forming an arch. The median nerve can be compressed by decreasing the size of the tunnel or increasing the size of the tendons (swelling within the tunnel). Flexing the wrist to 90 degrees will also decrease the size of the tunnel.
Symptoms such as pain and altered sensation (numbness, tingling) occur in the thumb, index, middle, and radial half of the ring finger, and often result in weakness in the thenar muscles (base of the thumb). Numbness often occurs at night as it is thought that wrists may become flexed during sleep. Loss of grip strength and generalized pain of the wrist and hand are also characteristic of this condition.
Carpal tunnel syndrome is often idiopathic (due to an unknown cause). However, there are some medical conditions that can lead to its onset such as: Obesity, hypothyroidism, arthritis, previous fractures of the wrist, diabetes, and pregnancy. In addition, work related risk factors, such as excessive force, lack of ergonomic positioning, vibrational forces, and repetitive movements have been shown to be associated with the onset of this condition.
The diagnosis of carpal tunnel involves a combination of the patient's history and description of symptoms, clinical findings, and electrodiagnostic testing. Patients often report altered sensation in the median nerve distribution, symptoms that occur while sleeping, and weakness in the thumb muscles. Clinically, tests such as the Phalen's maneuver and Tinel's sign can be performed in a physical assessment by a health care provider. Phalen's maneuver involves flexing the wrist for at least 60 seconds. A positive test is indicated when numbness and/or pain is felt in the median nerve distribution within 60 seconds. Tinel's sign is performed by lightly tapping over the carpal tunnel. A positive result is indicated if the tapping causes a tingling sensation in the median nerve distribution. Electrodiagnostic testing may include nerve conduction tests that can determine median nerve abnormalities.
Prevention of carpal tunnel syndrome involves avoiding repetitive movements, adopting more ergonomic positions and/or the use of ergonomic equipment. Treatment may include bracing/splinting of the wrist, physiotherapy, or surgery. Physiotherapy treatments may include ultrasound, exercise and stretching prescription, and/or manual mobilization by your physiotherapist. Please check with your primary health care provider to determine a diagnosis for your wrist pain and the most appropriate treatment plan for your condition.