sone nan sangcheoneun baro sodokhaeya hae.

Here, 손에 means on the hand or in the hand area.

The particle 에 is used because the verb 나다 often marks the place where something appears or occurs. So:

• 손에 상처가 나다 = for a wound to appear on the hand
• 얼굴에 뾰루지가 나다 = for a pimple to appear on the face

So 손에 난 상처 is literally something like a wound that appeared on the hand.

No. In this sentence, 난 is not the pronoun-related 난.

Here, 난 comes from the verb 나다 (to arise, occur, appear) and is the form used before a noun.

• 나다 → 난 before a noun
• 손에 난 상처 = the wound that appeared on the hand

So this 난 is describing 상처.

Because 손에 난 상처 sounds more natural for a wound that has appeared on the hand.

Compare:

• 손에 난 상처 = a wound on the hand / a wound that appeared on the hand
• 손의 상처 = the hand's wound

The second one is grammatical, but it sounds less natural in everyday speech for this situation. Korean often prefers a descriptive phrase with a verb, especially with things like injuries, rashes, pimples, and symptoms.

는 marks 상처 as the topic.

So the sentence has a structure like:

• 손에 난 상처는 = as for wounds on the hand
• 바로 소독해야 해 = you have to disinfect them immediately

This is very natural in Korean. English usually does not mark a topic this way, so it can feel unusual at first.

Because the sentence is built as a topic-comment sentence, not just a simple object sentence.

Two natural versions are:

• 손에 난 상처는 바로 소독해야 해.
• 손에 난 상처를 바로 소독해야 해.

The difference:

• 상처는: As for wounds on the hand, they should be disinfected immediately.
• 상처를: You should disinfect the wound on the hand immediately.

With 는, the wound is introduced as the topic, and the object of 소독해야 해 is understood from context.

바로 here means immediately, right away, or without delay.

So it emphasizes that disinfecting should happen as soon as possible.

Depending on context, 바로 can also mean things like:

• directly
• right
• exactly

But in this sentence, immediately is the right sense.

소독해야 해 comes from:

• 소독하다 = to disinfect
• -아/어야 하다 = have to / must

So:

• 소독해야 하다 = to have to disinfect
• 소독해야 해 = casual spoken form of that

It expresses obligation or strong advice: must disinfect / should disinfect.

The subject is omitted because Korean often leaves it out when it is obvious or general.

In this sentence, the meaning is something like:

• You should disinfect it immediately
• One should disinfect it immediately
• It needs to be disinfected immediately

Which one sounds best depends on the English translation, but Korean does not need to state the subject explicitly here.

Yes. The ending 해 is casual speech.

So 손에 난 상처는 바로 소독해야 해 sounds natural in:

• conversation
• advice to a friend
• talking to someone younger
• casual everyday situations

A more polite version would be:

• 손에 난 상처는 바로 소독해야 해요.

A more formal version could be:

• 손에 난 상처는 바로 소독해야 합니다.

Yes, you could, but the nuance is a little different.

• 손에 난 상처 = a wound that has appeared on the hand
• 손에 있는 상처 = a wound that is on the hand

난 sounds more natural when talking about a wound, rash, sore, or other condition that has come up on the body.
있는 is more neutral and just describes existence/location.

So in this context, 손에 난 상처 is the more idiomatic choice.

Yes. This is a very common Korean pattern.

Korean often uses 나다 for things that appear on the body:

• 상처가 나다 = to get a wound
• 땀이 나다 = to sweat / sweat comes out
• 열이 나다 = to have a fever
• 뾰루지가 나다 = to get a pimple
• 피가 나다 = to bleed / blood comes out

So 손에 난 상처 fits a very common and natural Korean way of describing physical conditions.