Final answer:
Underneath the hook of the hamate bone, as part of the carpal tunnel structures, the ulnar nerve and artery pass through. The tunnels formed by the carpal bones and the flexor retinaculum allow muscle tendons and nerves to reach the hand.
Step-by-step explanation:
The structure that travels underneath the hook of the hamate is among the tendons and nerves passing through the carpal tunnel. Specifically, the ulnar nerve and ulnar artery pass through Guyon's canal, a space that is bordered by the hook of the hamate. In the articulated hand, the carpal bones and the flexor retinaculum form the carpal tunnel. The roof of the carpal tunnel is the flexor retinaculum, which attaches medially to the hamate bone. The flexor retinaculum helps maintain the U-shaped grouping of carpal bones and creates a passageway for tendons from nine muscles of the anterior forearm and an important nerve (likely the median nerve) to enter the hand, thereby facilitating hand and finger mobility.