Om hennes fot fortfarande är svullen imorgon, vill hon få den undersökt.

Here om means if.

In Swedish, om is commonly used to introduce a condition:

• Om det regnar, stannar vi hemma. = If it rains, we stay home.
• Om hennes fot fortfarande är svullen imorgon... = If her foot is still swollen tomorrow...

A learner may already know om as about, and that is also correct in other contexts:

• Vi pratar om boken. = We are talking about the book.

So om can mean different things depending on context.

Because Swedish uses V2 word order in main clauses.

That means the finite verb usually comes in the second position. In this sentence, the whole if-clause comes first:

• Om hennes fot fortfarande är svullen imorgon = first position

So in the main clause, the verb must come next:

• vill hon få den undersökt

That is why you get:

• Om ..., vill hon ...

and not:

• Om ..., hon vill ...

This is very common in Swedish:

• Imorgon ska jag jobba.
• Om det blir kallt, stannar vi inne.
• När han kommer, börjar vi.

Because sin/sitt/sina refers back to the subject of the same clause.

In the clause Om hennes fot fortfarande är svullen imorgon, the subject is hennes fot. The word hon is not the subject inside that clause, so Swedish does not use sin there.

So:

• hennes fot = her foot

But compare:

• Hon tvättar sin fot. = She is washing her own foot.

There, hon is the subject of the clause, so sin works.

This is a very important Swedish difference from English.

Den refers back to fot.

The noun fot is an en-word in Swedish:

• en fot

When you replace an en-word with a pronoun, you usually use den:

• Jag ser foten. Jag ser den.

If the noun were an ett-word, you would usually use det instead.

So here:

• hennes fot → den

Svullen is the adjective form meaning swollen.

It agrees with the noun it describes. Since fot is:

• singular
• common gender (en word)

the adjective is:

• svullen

Compare:

• en svullen fot = a swollen foot
• ett svullet öga = a swollen eye
• svullna fötter = swollen feet

In this sentence, the adjective comes after är, so it is a predicative adjective, but agreement still matters:

• foten är svullen

Because in a subordinate clause, words like fortfarande, inte, alltid, and similar adverbs often come before the finite verb.

So you get:

• Om hennes fot fortfarande är svullen imorgon

Compare with a main clause:

• Hennes fot är fortfarande svullen.

So the placement changes depending on the clause type:

• main clause: subject + verb + adverb
• subordinate clause: subject + adverb + verb

This is a very common pattern in Swedish.

This is a very common Swedish structure.

få + object + participle often means get/have something done.

So:

• få den undersökt = get it examined / have it examined

Other examples:

• Hon vill få håret klippt. = She wants to get her hair cut.
• Jag måste få bilen lagad. = I need to get the car repaired.
• Han fick armen undersökt. = He got his arm examined.

So få here does not mean simply receive. It is part of a construction meaning that someone arranges for something to be done.

Yes, in this kind of construction it behaves like a past participle and can agree in form.

In this sentence, the form is:

• den undersökt

Here the agreement is not very visible, because the singular form is undersökt.

But compare:

• få foten undersökt = get the foot examined
• få fötterna undersökta = get the feet examined

So the plural form changes to undersökta.

A useful thing to remember is that the agreement may be easier to notice in plural than in singular.

Because Swedish usually says simply imorgon for tomorrow.

You do not need a preposition like on or in.

So:

• imorgon = tomorrow

This works just like English in that sense:

• vi ses imorgon = we’ll see each other tomorrow

Also, both spellings are used:

• imorgon
• i morgon

Both are accepted.

Not always.

In modern Swedish, commas are generally used less than in English. A sentence like this can often be written with or without the comma:

• Om hennes fot fortfarande är svullen imorgon, vill hon få den undersökt.
• Om hennes fot fortfarande är svullen imorgon vill hon få den undersökt.

The comma can help readability by clearly marking the end of the opening clause, but it is not always required.

So a learner should recognize both versions.