Skuldersømmen og sidesømmen sitter riktig.

Because -en is the definite article attached to the noun.

In Norwegian, instead of usually putting a separate word like the in front, you often add the definiteness to the end of the noun:

• en søm = a seam
• sømmen = the seam

So:

• skuldersømmen = the shoulder seam
• sidesømmen = the side seam

This sentence is talking about specific seams, probably on a particular garment, so the definite form is used.

They are compound nouns, which are very common in Norwegian.

• skulder = shoulder
• side = side
• søm = seam

So:

• skuldersøm = shoulder seam
• sidesøm = side seam

Then the definite ending -en is added:

• skuldersømmen = the shoulder seam
• sidesømmen = the side seam

A useful thing to notice is that Norwegian often combines words directly where English may use two separate words.

Yes, sitte literally means to sit, but in Norwegian it is also used much more broadly than English sit.

Here, sitter means something like:

• is positioned
• lies
• is placed
• fits in the right place

In clothing and tailoring language, sitte is very common when talking about how something fits or lies on the body.

So Skuldersømmen og sidesømmen sitter riktig means that the seams are in the correct position or sitting correctly on the garment/body.

This is very natural Norwegian.

Because er riktig would mean something more like is correct/right in a general sense, while sitter riktig describes placement or fit.

Compare the difference:

• Det er riktig. = That is correct.
• Den sitter riktig. = It fits / sits correctly.

With seams, the important idea is not just abstract correctness, but that they are lying in the right place. That is why sitter is the better verb here.

Because riktig is being used as an adverb, not as an adjective describing the nouns directly.

It modifies the verb sitter:

• sitter riktig = sits correctly

If it were an adjective directly describing plural nouns, you might expect a plural form like riktige. But that is not what is happening here.

So:

• riktige sømmer = correct seams
• sømmene sitter riktig = the seams sit correctly

That is an important difference.

Because Norwegian verbs do not change for singular and plural the way English verbs sometimes do.

In English:

• the seam sits
• the seams sit

In Norwegian, the verb form stays the same:

• sømmen sitter
• sømmene sitter

So even though there are two things, sitter is still the correct form.

Og simply means and.

So:

• Skuldersømmen og sidesømmen = The shoulder seam and the side seam

It joins the two nouns into one coordinated subject.

Yes, but it means something slightly different.

• Skuldersømmen og sidesømmen sitter riktig = the seams are positioned correctly / fitting correctly
• Skuldersømmen og sidesømmen er riktige = the seams are the correct ones or are correct

The original sentence is better if you are talking about fit, alignment, or placement on a garment.

Because Norwegian usually marks definiteness by adding it to the noun itself.

English:

• the shoulder seam

Norwegian:

• skuldersømmen

This is one of the biggest structural differences English speakers notice early on.

Very often:

• a car = en bil
• the car = bilen

The same pattern is used here.

Most likely, yes.

Because both nouns are in the definite singular:

• skuldersømmen = the shoulder seam
• sidesømmen = the side seam

That usually suggests specific seams on a specific piece of clothing being discussed, checked, or fitted.

The indefinite forms would be:

• en skuldersøm = a shoulder seam
• en sidesøm = a side seam

If you wanted the plural:

• skuldersømmer = shoulder seams
• sidesømmer = side seams

And definite plural:

• skuldersømmene = the shoulder seams
• sidesømmene = the side seams

So the sentence specifically uses the definite singular forms.

Yes, it is very normal.

The basic pattern is:

subject + verb + adverb

So here:

• Skuldersømmen og sidesømmen = subject
• sitter = verb
• riktig = adverb

This is a standard declarative sentence in Norwegian.

A very literal version would be:

The shoulder seam and the side seam sit correctly.

That sounds a bit unusual in normal English, but it helps show how Norwegian is thinking about the situation: the seams are sitting or lying where they should.

A more natural English translation would usually be something like:

• The shoulder seam and side seam are in the right place.
• The shoulder seam and side seam fit correctly.
• The shoulder seam and side seam are positioned correctly.