Hi,
there should 5V exactly where you expect them between the sockets labeled 5V and GND on the "Power" section.
That's the theory at least. So you either doing something wrong while measuring (wires to your meter don't have good contact inside the socket on the arduino maybe) or there is a hardware problem.
If you got steady hands maybe you could try to measure the voltage between the pins from the backside. But be careful not to short-circuit the power supply when trying.
Eberhard