BACKGROUND: Compression of the median nerve at the wrist, or carpal tunnel 
syndrome, is the most commonly recognized nerve entrapment syndrome. Carpal 
tunnel syndrome is usually caused by compression of the median nerve due to 
synovial swelling, tumor, or anomalous anatomical structure within the carpal 
tunnel.
METHODS: During a routine carpal tunnel decompression, a large vessel was 
identified within the carpal tunnel.
RESULTS: The large vessel was the radial artery. It ran along the radial aspect 
of the carpal tunnel just adjacent to the median nerve.
CONCLUSIONS: The unusual presence of the radial artery within the carpal tunnel 
could be a contributing factor to the development of carpal tunnel syndrome. In 
this case, after surgical carpal tunnel release, all symptoms of carpal tunnel 
syndrome resolved.