What is the correct central ray positioning for the tangential projection, Gaynor-Hart method, for the carpal canal?

The central ray positioning for the tangential projection using the Gaynor-Hart method is set to be angled about 25-30 degrees to the long axis of the hand. This specific angling is crucial for effectively visualizing the carpal canal and the relationship of the carpal bones, particularly the pisiform and hamate, as well as the surrounding soft tissue structures.

By angling the central ray in this manner, the radiographic image provides a clearer view of any potential abnormalities such as carpal tunnel syndrome, fractures, or other pathology that may not be as discernible with a perpendicular or shallow angle. The methodology behind the Gaynor-Hart projection highlights the importance of the correct angulation to maximize the diagnostic quality of the resulting images, ensuring the structures of interest are adequately highlighted.

Choosing a perpendicular position or any other angle that does not adhere to the recommended 25-30 degrees would compromise the clarity of the anatomical details necessary for proper evaluation and diagnosis.