How effectively does Wilfred Owen portray the physical and mental suffering of individual soldiers in his war poetry?

Wilfred Owen is considered by many scholars to be among the greatest poets of the First World War and is hailed as perhaps the greatest war poet in the English language. His poetry is described as indignant, vivid and visceral -- in stark protest against the destruction of human life and dignity in war. It pulses with the true agonies of battle which, Owen felt, get buried beneath national propaganda and fantasies of glory. So impassioned was he to strip war of its rousing fictive quality that he made it the central aim of his poetry:

Above all I am not concerned with Poetry. My subject is War, and the pity of War. The Poetry is in the Pity.

Owen's most famous poem, Dulce et Decorum Est -- a Latin phrase taken from the poet Horace meaning "It is sweet and fitting to die for one's country" -- depicts the suffering of men with whom he fought alongside.

If you could hear, at every jolt, the blood 

Come gargling from the froth-corrupted lungs, 

Obscene as cancer, bitter as the cud 

Of vile, incurable sores on innocent tongues

Here Owen is using evocative description to disabuse us of the heroic fantasies of war, of the fact that it doesn't offer you dignity in death but in fact strips us of any humanity and dignity whatsoever.

His use of alliteration and repetition together give the reader a sense of urgent reality: "He plunges at me, guttering, choking, drowning." Also seen in the beginning line in Exposure: "Our brains ache, in the merciless iced east winds that knive us . . . " and "Worried by silence, sentries whisper, curious, nervous, / But nothing happens." Owen cleverly builds tension by showing us that in war even in silence there is a terror: the dread of anticipation. This is one aspect of the mental suffering of war. 

While his style was certainly musical and in-keeping with modernist trends, Owen wrote to confront his traumatic experiences in the trenches after he had been hospitalized with what was then called "Shell-shock." Encouraged by his doctor and by his close friend -- fellow poet Siegfried Sassoon -- Owen relived his experiences in his poetry. One such poem called Sentry recounts a moment during the war when he witnessed a solider blinded by a shell:

I held a flame against his lids
And said if he could see the least blurred light
He was not blind; in time he'd get all right.
"I can't," he sobbed. Eyeballs, huge-bulged like squids
Watch my dreams still...

It is in these memorable lines that we hear the numb and tormented voice of Owen, holding a lantern to the excruciating face of a fellow solider. He was tremendously effective in portraying the pathos of suffering during the First World War through his poetry.