У ребёнка болит ножка.

Russian often expresses someone has pain somewhere with the pattern:

у + person in the genitive + болит / болят + body part

So У ребёнка болит ножка literally works like:

At the child, the leg hurts
which naturally means
The child has a sore leg / The child’s leg hurts.

This is a very common Russian structure for pain and physical discomfort.

Because after the preposition у, Russian uses the genitive case.

The dictionary form is ребёнок = child.
After у, it becomes ребёнка.

So:

• ребёнок = child
• у ребёнка = at the child / the child has

This is not a direct subject form; it is part of the possession/experiencer structure.

Because the grammatical subject of болит is ножка, and ножка is singular.

Compare:

• болит ножка = the leg hurts
• болят ноги = the legs hurt

So the verb agrees with the thing that hurts, not with the person experiencing the pain.

Болит is the 3rd person singular of болеть and here means hurts / is hurting / aches.

In sentences about body parts, Russian usually uses болеть like this:

• У меня болит голова. = My head hurts.
• У него болят зубы. = His teeth hurt.

So in your sentence, болит means hurts.

Ножка is a diminutive form of нога.

• нога = leg
• ножка = little leg / dear leg

With children, body parts are very often referred to with diminutives because it sounds affectionate, gentle, or child-related. So ножка is very natural here.

Depending on context, it may simply sound tender rather than literally meaning the leg is small.

Usually ножка is from нога, so its basic meaning is leg.

However, in everyday speech, especially with children, нога / ножка can sometimes cover the whole lower limb more loosely than English does. So depending on context, an English translation might be leg or sometimes foot.

Still, grammatically, it is the diminutive of нога.

Yes, that is a good literal breakdown for understanding the grammar, but it is not natural English.

A natural translation would be something like:

• The child’s leg hurts.
• The child has a sore leg.
• The child’s little leg hurts.

Literal translations are useful for seeing structure, but idiomatic English will sound different.

It is singular.

• ребёнка here = genitive singular of ребёнок
• genitive plural of ребёнок would be different in a full phrase and would not mean the same thing here

So у ребёнка means the child has..., not the children have...

Russian does not have articles like the and a/an.

Whether something is definite or indefinite is understood from context.

So ребёнка can mean the child or a child, depending on the situation, and ножка can mean the leg or a leg.

In a normal context, У ребёнка болит ножка is usually understood as The child’s leg hurts.

Yes. Russian word order is flexible, and changing it can shift emphasis.

For example:

• У ребёнка болит ножка. = neutral, common wording
• Ножка у ребёнка болит. = emphasizes the leg
• Болит ножка у ребёнка. = possible, often more context-driven

The basic meaning stays the same, but the most neutral version is the one you were given.

No, that would not be the normal way to express this meaning.

For pain in a body part, Russian typically uses:

У кого? болит что?

So:

• У ребёнка болит ножка.

You usually do not make ребёнок the grammatical subject in this kind of sentence.

The correct spelling is ребёнка, with ё, because it comes from ребёнок.

In many printed texts, Russian often replaces ё with е, so you may also see:

• ребенка

But the pronunciation is still with yo: rye-BYON-ka.

For learners, it is very helpful to remember the ё, because it shows the correct pronunciation.

No. Болеть can also be used more generally for pain or illness.

For example:

• У меня болит голова. = My head hurts.
• У меня болит спина. = My back hurts.
• Он болеет. = He is ill / He is sick.

But in your sentence, it is specifically the body-part pain pattern.

You would make the body part plural, and the verb would also become plural:

• У ребёнка болят ноги.

So compare:

• У ребёнка болит ножка. = The child’s leg hurts.
• У ребёнка болят ноги. = The child’s legs hurt.

This is a very useful pattern to memorize.

It sounds very natural and slightly tender because of ножка.

• нога would be more neutral
• ножка sounds affectionate, gentle, or suitable when talking about a child

So this sentence is perfectly normal, especially in everyday speech about a small child.