The fathers reached the chapel through the arcade of the large cloister. However; for the faithful entering from outside, the monastery could be accessed through a low portico at the entrance. The entry has a white, veined marble framed door with corbels supporting a painted lunette with a fresco executed by a follower of Niccolò di Tommaso between 1371 and 1374. In the fresco the Virgin and Child are surrounded by St Bruno, Queen Giovanna, St Giacomo and Count Arcucci who offers a model of his church to the Blessed Mother.

The single nave is rectilinear and divided into three spans by three pairs of pilasters which support neautiful pointed cross vaults with sharp corners. The mullioned window with three lights at the far end was installed during the restoration of 1927 as a replacement for a large rectangular window. It was modeled after an inlay from the Certosa di San Martino.