Flexor Tendon Injuries - Is There a Black Box in the Palm of the Hand?

The back of the hand is a very exposed area where there isn't much padding. There's this sort of black box in the middle of the palm of the hand that we were all taught is a very dangerous zone to have tendon lacerations. If you can see the ends of the flexor tendon, by all means tag it with a suture and leave a long tail. It makes life easier for the operating room.