Which wrist ratio index threshold is used to support a diagnosis of carpal tunnel syndrome?

• A. Not less than 0.75
• B. Not less than 0.67
• C. Not less than 0.55
• D. Not less than 0.60

Answer: (B)

The wrist ratio index is a critical measurement used in the assessment of carpal tunnel syndrome. The correct threshold for the wrist ratio index, which is calculated by dividing the wrist width by the thickness of the wrist, is established at not less than 0.67. This threshold helps differentiate between individuals at risk for carpal tunnel syndrome and those who are not.

Research indicates that a wrist ratio index below 0.67 indicates a higher risk of developing symptoms associated with carpal tunnel syndrome. This is due to the anatomy of the wrist and how it relates to the median nerve's space within the carpal tunnel. A lower wrist ratio can suggest a bulkier wrist and more potential compression of the structures within the carpal tunnel, which can lead to the characteristic symptoms of numbness, tingling, and pain.

Thus, when evaluating patients with symptoms consistent with carpal tunnel syndrome, using a threshold of 0.67 provides a standardized metric that supports the diagnosis and guides treatment options effectively.