What does the structure of this short story say about Montresor’s perception of the events in the story?

Since narrative structure is composed of form and content, both contribute to Montresor's twisted and consuming perception of his plans of revenge since the author, Edgar Allan Poe, held that every element in a tale must contribute to the effect that is intended. 

Form: There are two forms to this story: that of the arabesque, and that of a mock celebration of a Mass.

1. Poe's use of the arabesque, a fanciful pattern of narrative that moves forward and returns to the initial disturbing idea, suggests the twists and turns of Montresor's mind.

The narrator Montresor begins and ends his tale with statements about his plan of revenge, a revenge by which he is consumed. He first explains the conditions that define it; then, he applies these conditions of avenging himself as he leads Fortunato into the catacombs. But at the same time, he feigns his doubts about the Amontillado. For, he says that he does not wish to impose upon Fortunato's time--"I perceive that you have an engagement"--and he acts as though he is concerned that the connoisseur be exposed to the severe cold in the catacombs. These actions are taken to distract Fortunato from Montresor's purpose as he circles back and then moves forward again.

The narrative continues to move in this forward/halting manner (arabesque) that continues to suggest Montesor's intent to avenge himself. For instance, the antipathy which Montresor feels toward Fortunato becomes more evident with his parodying of the Order of the Masons with the trowel, which is, ironically, the tool of stonemasons who originated this secret fraternal order. With this action, therefore, Montresor moves closer to his revenge as he holds up the very trowel that he will soon use to imprison Fortunato. With his trowel, Montresor underscore the motto of the family coat of arms that he has previously explained to Fortunato.

After Montresor walls in Fortunato, he completes his revenge, insanely echoing the shouts of Fortunato and fulfilling the last condition of revenge that the avenger make himself felt. Montesor ends with a Latin phrase to reflect the Latin on his coat of arms, as well as boasting of his act of revenge. 

2. Another form that Montresor follows in his plan for revenge is that of a parody of the celebration of the Mass. The procession in to the catacombs with the flambeaux mimics the commencement of the celebration of the Mass.  Poe perverts the ordinarily sacred ceremony into a black mass by altering the significance of wine to celebrate a sadistic ritual with profane signs and movements, such as the leading of Fortunato through the catacombs. Further, Fortunato arranges a mock crucifixion with the fettering of Fortunato to the wall, an action that completes the final stage of Montresor’s vendetta. 

Content: The employment of reverse psychology by Montresor demonstrates the perversity of his mind as well as how skewered the relationship between Montresor and his victim really is.

Continually, Montresor says to Fortunato, "We will go back; you will be ill, and I cannot be responsible." Repeatedly, he teases Fortunato into thinking he is concerned about the connoisseur's health, while at the same time Montresor leads his victim deeper and deeper into the catacombs. And, yet when he has Fortunato fettered against the wall and builds other walls around him, Montresor seems to worry when he hears no more from Fortunato. 

Certainly, the structure of Poe's story indicates the nefarious nature of Montresor's plan of revenge and the twists of his mind, some of which indicate where the real horror lies; namely, in what human beings are capable of doing to one another.