Она отпустила мою руку.

Because the subject is она (she), and Russian past-tense verbs agree with the subject in gender and number.

• отпустил = masculine singular
• отпустила = feminine singular
• отпустило = neuter singular
• отпустили = plural

So with она, you need отпустила.

The infinitive is отпустить.

This is a perfective verb, meaning the action is seen as completed: she let go / released my hand.

Its imperfective partner is отпускать.

• Она отпускала мою руку. = She was letting go of my hand / used to let go of my hand.
• Она отпустила мою руку. = She let go of my hand.

Because it is the direct object of the verb отпустить, so it goes in the accusative case.

The dictionary form is:

• моя рука = my hand

But in the accusative singular feminine, it becomes:

• мою руку

Both words change because мой and рука must agree in gender, number, and case.

So:

• nominative: моя рука
• accusative: мою руку

Because рука is a feminine noun, and here it is in the accusative singular.

For many feminine nouns ending in -а, the accusative singular ends in -у:

• рука → руку
• книга → книгу
• машина → машину

So Она отпустила мою руку uses the accusative because the hand is what she released.

For the same reason: мой has to match the noun it describes.

Since руку is:

• feminine
• singular
• accusative

the possessive adjective must also be:

• feminine
• singular
• accusative

So:

• nominative: моя рука
• accusative: мою руку

It can mean hand or arm, depending on context.

Russian рука often covers the whole upper limb more broadly than English hand does. In this sentence, Она отпустила мою руку, the natural English translation is usually She let go of my hand, because that is the most likely situation.

If Russian specifically wants to say hand as the part below the wrist, it can use кисть, but that is much more anatomical and less common in everyday speech.

Because Russian expresses this idea differently from English.

In English, you say let go of something.
In Russian, отпустить simply takes a direct object:

• отпустить руку = to let go of a hand
• отпустить меня = to let me go
• отпустить собаку = to release the dog

So there is no separate word corresponding to English of here.

Yes. Russian word order is more flexible than English word order.

The neutral order here is:

• Она отпустила мою руку.

But you could also hear:

• Мою руку она отпустила.
• Она мою руку отпустила.
• Отпустила она мою руку.

These variations change emphasis more than basic meaning.

For example:

• Мою руку она отпустила. may stress my hand
• Отпустила она мою руку. may sound more narrative or emphatic

Still, the original sentence is the most straightforward and neutral.

Yes, sometimes.

Russian often drops subject pronouns when the subject is clear from context:

• Отпустила мою руку. = She let go of my hand.

Because отпустила is feminine singular past, it already suggests she.

However, она is included when the speaker wants to be explicit, contrastive, or simply clearer.

Here it means to let go, to release, or to loosen one’s hold on something.

Common uses of отпустить include:

• отпустить руку = let go of a hand
• отпустить пленника = release a prisoner
• отпустить волосы = grow one’s hair long
• отпустить шутку = make/crack a joke

So the exact translation depends on context. In this sentence, let go of my hand is the most natural.

No, not in this sentence.

Свой refers back to the subject of the sentence. The subject here is она.

So:

• Она отпустила свою руку. = She let go of her own hand.
  (This is odd in normal logic, but grammatically that is what it means.)

Because the hand belongs to the speaker, Russian uses:

• мою руку = my hand

So мою is correct.

The normal stress is:

• Она́ отпусти́ла мою́ ру́ку.

A rough pronunciation guide:

• она́ = ah-NA
• отпусти́ла = aht-poo-STEE-lah
• мою́ = ma-YU
• ру́ку = ROO-koo

The stressed syllables are important in Russian, so it helps to learn the words together with stress.

Yes, it is completely natural.

It is a normal way to say:

• She let go of my hand.
• She released my hand.

In everyday speech, this is exactly the kind of structure Russian uses: subject + past-tense verb + direct object in the accusative.