All of the following structures passes through the guyon's canal, EXCEPT:

Guyon's canal is located superficially on the ulnar side of the carpus. The contents of this canal are the ulnar nerve which divides into superficial and deep palmar branch, ulnar aery and vein. Guyon's canal is bounded on the ulnar side by the pisiform, the hook of hamate, and hypothenar muscles. On the dorsal side it is bounded by flexor retinaculum and on the palmar side by the palmar carpal ligament. Ref: Diagnostic Imaging of the Hand By Rainer Schmitt,page 91.