In typical Eastern fashion, the icon known as "She who is more spacious than the heavens" (Greek: "Πλατυτέρα" or translit: “Platytera Ton Ouranon” or simply "Platytera") is found in the most prominent position at the Sanctuary, overwhelming the worshipper and overshadowing all other icons and sacred art (Figure 1).
Set against a gold background within two round arches under which hang the seven lampstands (aesthetically these are censers); in the Sanctuary they are represented as having gone out into all the earth. , , . In the Platytera we see more than in any other, the icon's true function: to make real that which is represented:
The architectural placement of the Platytera, between the ceiling and the floor powerfully illustrates that she is the person through whom heaven and earth are united. She is called in our Hymnography; “the heavenly ladder, whereby God has descended” and as “the Bridge leading those on earth to heaven”[....] Her icon unites Christ’s ceiling icon of the “Pantocrator” with those of us below. The Mother of God, stands between the heavens and the earth and serves as a bridge. 
In the interpretation of the Sanctuary, it is the Resurrected Christ (not the Child Jesus) who bursts forth from the womb more spacious that the universe, with the radiance of the divine energies. The visual representation of the energies tell us in no uncertain terms that this is Jesus Son of Mary, incarnate of the Holy Spirit. The outstretched and raised arms ("Orans") is a familiar motif in the catacombs of both Jew and Gentile, depicting Old Testament saints as intercessors and asking the Lord to deliver the soul of the person on whose tombs they are depicted:
Among the subjects depicted in the art of the Roman catacombs  one of those most numerously represented is that of a female figure with extended arms known as the Orans, one who prays. The custom of praying in antiquity with outstretched, raised arms was common to both Jews and Gentiles; indeed the iconographic type of the Orans was itself strongly influenced by classic representations [....] But the meaning of the Orans of Christian art is quite different from that of its prototypes. Numerous Biblical figures, for instance, depicted in the catacombs — Noah, Abraham, Isaac, the Three Children in the Fiery Furnace, Daniel in the lions' den—are pictured asking the Lord to deliver the soul of the person on whose tombs they are depicted as He once delivered the particular personage represented.
In this New Testament idealisation, these figures also assume the same "ancient attitude of prayer" but are depicted as the prototype of the deceased's (resurrected) soul in heaven:
But besides these Biblical Orans figures there exist in the catacombs many ideal figures (153 in all) in the ancient attitude of prayer, which, according to Wilpert, are to be regarded as symbols of the deceased's soul in heaven, praying for its friends on earth. This symbolic meaning accounts for the fact that the great majority of the figures are female, even when depicted on the tombs of men. One of the most convincing proofs that the Orans was regarded as a symbol of the soul is an ancient lead medal in the Vatican Museum showing the martyr, St. Lawrence, under torture, while his soul, in the form of a female Orans, is just leaving the body. An arcosolium in the Ostrianum cemetery represents an Orans with a petition for her intercession: Victoriæ Virgini . . . Pete . . . 
It is in the testimony of the saints that we see the idea of the soul as having a more direct lineage to Mary (the true virgin prototype):
The Acts of St. Cecilia speaks of souls leaving the body in the form of virgins: "Vidit egredientes animas eorum de corporibus, quasi virgines de thalamo", and so also the Acts of Sts. Peter and Marcellinus. Very probably the medieval representations of a diminutive body, figure of the soul, issuing from the mouths of the dying, to be received by angels or demons, were reminiscences of the Orans as a symbol of the soul. The earlier Orantes were depicted in the simplest garb, and without any striking individual traits, but in the fourth century the figures become richly adorned, and of marked individuality — an indication of the approach of historic art. One of the most remarkable figures of the Orans cycle, dating from the early fourth century, is interpreted by Wilpert as the Blessed Virgin interceding for the friends of the deceased. Directly in front of Mary is a boy, not in the Orans attitude and supposed to be the Divine Child, while to the right and left are monograms of Christ. 
It is not surprising that the Sanctuary should serve as a kind of giant reliquary, with the remains of ancient parishioners, functionaries and saints held (and displayed) awaiting the great day of their awakening and redemption (Figure 2, 3, 4).
Figure 2: One of two ossuaries in the Sanctuary. The glass
lid was removed when this photo was taken. This one being
in the corridor that connects the sacristy to the Sanctuary,
the other being in what is now the museum housing
mementos of Blessed John Paul II's visit on 26th May 1990.
(Photo: Author on 17 August 2013)
Figure 3: The skull and other relics of Saint Vincent are
displayed in the altar. The altarpiece (oils on canvas) depicts
Photo: Author on 17 August 2013
Figure 4: The tomb of Fr. Paulus Lebrun who served as
the parish priest of the Sanctuary between 1844 and 1849.
His tomb lies in front of the relics of St. Vincent.
(Photo: Author on 26 August 2013)
The Sanctuary combines the symbology of worshippers in the modern era. In a more recent interpretation, we see the prominent display of the "M" who begot God and who serves as bridge between the highest heavens above (Figure 5) and the earth below (Figure 6).
Figure 5: Stainless steel motif
symbolising Mary ("M") inset
within a motif of the Sacred,
Immaculate and Glorious Heart.
(Photo: Author on 17 August 2013)
 Blue Letter Bible: Tyropoeon Valley. In ancient Israel the use of the arch in architecture is almost unknown. Nonetheless, this example reminds us of the arch (q.v.) of the bridge between Mount Moriah and Mount Zion (called "Robinson's Arch"), where it projects from the sanctuary wall. It was discovered by Robinson in 1839. This arch was destroyed by the Romans when Jerusalem was taken. The western wall of the temple area rose up from the bottom of the valley between Moriah and Zion to the height of 84 feet, where it was on a level with the area, and above this, and as a continuance of it, the wall of Solomon's cloister rose to the height of about 50 feet, "so that this section of the wall would originally present to view a stupendous mass of masonry scarcely to be surpassed by any mural masonry in the world." Accessed 31st August 2013.
 Revelation 4:5; Exodus 25:31-40
Waal, A. (1908). Roman Catacombs. In The Catholic Encyclopedia. New York: Robert Appleton Company. Retrieved August 31, 2013 from New Advent:http://www.newadvent.org/cathen/03417b.htm
(1911). Orans. In The Catholic Encyclopedia. New York: Robert Appleton Company. Retrieved August 31, 2013 from New Advent:http://www.newadvent.org/cathen/11269a.htm