Anatomy Interview Question:

A fourth year medical student fell off a ladder while installing a flood light above his garage and put his arm through a garage door window. When he got up from his fall, he realized the glass had deeply cut the anterior aspect of his wrist and so he decided to go to the nearest emergency room. During his trip to the ER, he studied his wrist and began to make an initial diagnosis. Remembering his training, he initially assumed that the cut had affected all of the muscles in his wrist and he proceeded to examine all of them.

Since he was able to flex the distal phalangeal joints of his four medial digits and his thumb, he concluded the following muscles were uninjured?