Final answer:
Correct positioning for a Gaynor-Hart Carpal Tunnel Projection is confirmed when the U-shaped grouping of carpal bones, ligaments, and metacarpal articulations is clearly visible on the image, without any overlapping bones or compression of the median nerve.
Step-by-step explanation:
To ensure correct positioning for a Gaynor-Hart Carpal Tunnel Projection, the technician must have a clear understanding of the anatomy of the carpal region. The mnemonic "So Long To Pinky, Here Comes The Thumb" can help remember the arrangement of the carpal bones for this purpose.
When reviewing the resulting image, the carpal tunnel's outline should be visible, with the carpal bones forming the U-shaped grouping that creates the tunnel's walls and floor. The strong ligament, the flexor retinaculum, should be forming the roof of the canal, and it is secured laterally to the trapezium and scaphoid, and medially to the hamate and pisiform bones. The metacarpal bones should articulate with the distal carpal bones, indicating proper alignment.
The ideal projection will demonstrate no overlap of the carpal bones, clear visibility of the carpal tunnel's borders, and the median nerve should not appear compressed. Any deviation from this, with overlapping or obscured carpal bones, suggests incorrect positioning which may necessitate a retake of the X-ray.