Detached parts of the sentence are those secondary parts that assume a certain grammatical and semantic independence. This phenomenon is due to their loose connection with the words they modify.

Loose connection may be due to the position of these words, the way they are expressed, their meaning, or the speaker’s desire to make them prominent. In spoken language detached parts of the sentence are marked by intonation, pauses, and special stress; in written language they are generally separated by commas or dashes. Adverbial modifiers, attributes, and prepositional indirect objects may stand in loose connection to the word they modify, i. e. they may be detached (loose) parts of the sentence. The adverbial modifier is more apt to stand in loose connection than any other part of the sentence.

Any part of speech used in the function of an adverbial modifier may be detached, which accounts for the comma that separates it from the rest of the sentence.

The Corporal lit a pipe, carefully, because the enemy was close. (Heym)

In her excitement, Maria jammed the bedroom-door together. (London) One summer, during a brief vacation at Knocke, his visit had come to the notice of Harrington Brande… (Cronin)

An adverbial modifier expressed by the Nominative Absolute Participial Construction or any other absolute construction is generally detached.

The train coming in a minute later, the two brothers parted and entered their respective compartments. (Galsworthy)

With his face buried in his hands, he did not see her enter. the room.(Keating)

Of all the kinds of adverbial modifiers, that of attendant circumstances is most apt to become detached.

They drove on, without speaking again, to Stanhope Gate. (Galsworthy)

He came in, with a large parcel under his arm. (Collins)

She had moved through its gaudiness and pettiness and glamour, her head high and her lashes low, clothed in an immaculate dignity. (Sanborn)

Nicholas lay there, his brow still contracted, filled with perplexity and confusion. (Cronin)

The kitchen became the sitting room, she and Robert eating their meals before the warm stove. (Lawrence)

A detached attribute can modify not only a common noun as an ordinary attribute does but also a proper noun and a pronoun.

The crowd was now in constant uproar, yelling, gesticulating, beseeching and reviling with Latin intensity. (Cronin)

There was a star-like quality about Judice, radiant and unreachable. (Sanborn)

It was a wide white building, one storey high. (Sanborn)

Dumb with amazement, Mr. Gradgrind crossed to the spot where his family was thus disgraced. (Dickens)

Stout, middle-aged, full of energy, she bustled backwards and forwards from the kitchen to the dining-room. (Prichard)

The prepositional indirect object is often detached.

She does not change — except her hair. (Galsworthy)

A silver tray was brought, with German plums. (Galsworthy)

Huckleberry Finn was there, with his dead cat. (Twain)