Haavasta tuli verta.

Because -sta / -stä is the ending that often means out of / from.

• haava = wound
• haavasta = from the wound / out of the wound

This is called the elative case in Finnish.

So in this sentence, haavasta tells you the source that the blood is coming from.

Because verta is the partitive singular of veri (blood).

Finnish often uses the partitive when talking about:

• an indefinite amount
• a mass substance
• something not presented as a whole, countable item

Blood is usually treated as a substance, so verta is natural here: it means something like some blood or just blood in a mass sense.

Compare:

• veri = blood, the blood
• verta = blood / some blood (as a substance, an indefinite amount)

So Haavasta tuli verta is literally closer to From the wound came blood / some blood.

Because veri is an irregular-type noun.

Its forms are based on different stems:

• nominative: veri
• genitive: veren
• partitive: verta

So this is just one of those noun patterns that has to be learned.

A few useful forms:

• veri = blood
• veren = of the blood
• verta = blood / some blood
• veressä = in the blood

This kind of stem change is normal in Finnish, even though it can feel strange at first to an English speaker.

Yes, tulla normally means to come, and that basic idea is still there.

• tulla = to come
• tuli = came

In this sentence, Finnish uses tuli in a way that English often expresses as:

• came out
• started coming
• there came
• blood came from the wound

So Haavasta tuli verta is literally something like:

• From the wound came blood

Natural English usually says:

• Blood came out of the wound
• The wound started bleeding
• Blood was coming from the wound

So the verb is still come, but English and Finnish package the idea differently.

Finnish often builds that meaning into the case ending instead of using a separate word.

Here:

• haavasta already means from/out of the wound

So the combination

• haavasta tuli

already gives the idea came from the wound / came out of the wound.

English often needs a separate preposition or particle like from or out of, but Finnish can express that with the noun ending alone.

Yes, Verta tuli haavasta is also possible.

Finnish word order is more flexible than English word order. The different orders usually change focus or information structure, not the basic meaning.

Haavasta tuli verta

This starts with haavasta (from the wound), so the wound is the starting point or topic.

Verta tuli haavasta

This starts with verta (blood), so the blood is more in focus.

The original sentence sounds very natural because Finnish often puts a location/source element first in this kind of sentence.

Not in the usual straightforward way that an English noun is the subject.

In English, we would say:

• Blood came out of the wound

and blood is clearly the subject.

In Finnish, sentences like this are often built in an existential or appearance-of-something style. In that kind of sentence:

• the place/source may come first
• the thing appearing may be in the partitive
• the verb stays in 3rd person singular

So verta is the thing that appears, but grammatically it does not behave like a normal nominative subject.

That is why you get:

• Haavasta tuli verta

not a structure based on nominative veri.

Tuli is the past tense (more specifically, the Finnish imperfect) of tulla.

• tulla = to come
• tulee = comes / is coming
• tuli = came

So the sentence refers to something that happened in the past:

• blood came out of the wound
• blood started coming from the wound

If you wanted present tense, you could say:

• Haavasta tulee verta. = Blood is coming from the wound.

Yes. A very common alternative is to use vuotaa (to leak, to bleed in this context).

For example:

• Haava vuotaa verta. = The wound is bleeding.
• Haavasta vuotaa verta. = Blood is bleeding/coming from the wound.

The sentence Haavasta tuli verta is still correct, but it describes the event as blood coming from the wound, while vuotaa verta focuses more directly on bleeding.

So the difference is mostly about how the situation is framed:

• Haavasta tuli verta = blood came from the wound
• Haava vuotaa verta = the wound is bleeding

Because Finnish normally does not use articles.

English distinguishes:

• a wound
• the wound

Finnish simply has:

• haava
• haavasta, haavassa, etc. depending on case

So whether English translation uses a or the depends on context, not on a separate Finnish word.

In this sentence, haavasta could be understood as:

• from the wound
• from a wound

depending on the situation. Usually the broader context tells you which one is meant.