In any number of guide books to English cathedrals and also liturgiological texts, you can find the rood screen referred to as 'the rood screen or pulpitum'.
In the Sarum Missal, you can read (under the First Sunday in Advent, where a lot of the rubrics lie hidden) 'Et legatur Epistola in Pulpito omni die dominica…in omnibus vero aliis festis et feriis…ad Gradum chori legatur'. And similar directions are given for the Gospel: 'Et sic procedat diaconus per medium Chori, ipsum Textum super sinistrum manum solemniter gestando, ad Pulpitum accedat, thuribulo et ceroferario præcedentibus.'
This has led a number of authorities to conclude that the Gospel and Epistle were read from the top of the rood screen. This is patently absurd: I flatly refuse to believe that. If you look at the various examples of surviving rood screens, if they can be ascended at all, this is done via a narrow staircase accessed by a door, often as little as three feet (=1 metre) high. Possibly the rood screen at Salisbury (destroyed by Wyatt in his 'restoration') had more convenient access, but somehow I doubt that there would have been any dignified way for crucifers, acolytes, subdeacon and deacon, all vested and carrying bits and pieces, to have ascended to the top to sing their parts. It would at least have presented a comic sight.
My Cassells Latin Dictionary has 'pulpitum, a platform: Horace, esp. for actors 'the boards' of a theatre. Hor. Juv.'
My Latham's Revised Mediæval Latin Word-List (a marvellous book) has 'pulpit…ambo'.
Can it be that this long fantasy of the words of scripture being proclaimed from the top of the rood screen is simply that, a fantasy, and is a pulpitum simply, er, a pulpit?
Or a lectern such as the splendid original one in the middle of Merton College Chapel which we actually used for the reading of the Epistle and Gospel in the celebration you can access on the left?
I'd be really interested if anyone has any further information about this.
My suspicion is that a lot of research on the Sarum liturgy was done by Victorian Anglican rectors with plenty of time on their hands but no experience in actually performing solemn liturgy—that didn't really come in until the twentieth century, I think. Having never tried to sing the Gospel from a rood screen, the sheer impracticality didn't occur to them. Other things don't seem to have struck them, such as the fact that the nave in great churches (those with solid rood screens, on the whole) was not used for the gathering of large congregations. But more perhaps on this in another post.