There are two PITCH TRIM wheels on the mid pedestal. They have scales to set the CG for take-off. Inflight the CG scale is not valid but the indicator shows the position of the THS (trimmable horizontal stabilizer).
The THS is only controllable manually when on ground or when inflight in direct law. In direct law one uses the wheel to trim the pitch manually - therefore USE MAN PITCH TRIM is displayed on the PFD.
Oooops: two've been faster...