Medica frontem pueri tangit et dicit eum domi manere debere.

Medica is nominative singular feminine. It is the subject of the sentence, the person who touches and says something, so nominative is the expected case.

It also tells you that the doctor is female. A masculine form would be medicus.

Because frontem is accusative singular of frons, frontis. It is the direct object of tangit: the doctor is touching the forehead.

So:

• tangit = touches
• what does she touch? frontem

That is why the accusative is used.

Here pueri is genitive singular, so it means of the boy.

So frontem pueri means the boy’s forehead or literally the forehead of the boy.

This is a good word to notice, because pueri can also be nominative plural in other contexts, meaning boys. Here, however, the syntax clearly points to the genitive:

• frontem needs something to show whose forehead it is
• so pueri = of the boy

Because Latin often expresses reported speech or indirect statement without a separate word meaning that.

Instead, Latin uses the accusative-and-infinitive construction:

• dicit
• eum ... debere

Literally, the structure is something like:

• she says him to ought to stay at home

That is not natural English, so we translate it as:

• she says that he ought to stay at home

So the idea of that is there, but Latin shows it through grammar rather than with a separate word.

Because in an indirect statement, the subject of the reported clause goes into the accusative.

So in:

• dicit eum domi manere debere

eum is the person who is supposed to stay at home, but because this is inside reported speech after dicit, Latin uses accusative, not nominative.

A native English speaker often expects he, but Latin uses him in this structure:

• eum = him
• natural English translation = that he

Eum refers back to the boy.

Even though the boy appeared earlier as pueri in the genitive, that was only because he was part of frontem pueri = the boy’s forehead. In the indirect statement, he has a different grammatical job: he is the person who is supposed to stay at home. So Latin changes the form accordingly:

• pueri = of the boy
• eum = him

Same person, different case.

This happens because of the indirect statement after dicit.

The main reported verb is debere:

• eum ... debere = that he ought to...

Then manere depends on debere:

• debere manere = to ought to stay / more natural English: to have to stay, to be supposed to stay, to ought to stay

So:

• debere is the infinitive required by indirect statement
• manere is the infinitive that goes with debere

Together:

• eum domi manere debere = that he ought to stay at home

Domi means at home.

It is a special form called the locative, used with a small group of words to express place where, especially:

• domi = at home
• compare ruri = in the countryside

Because domi itself already means at home, Latin does not need a preposition like in there.

So:

• domi manere = to stay at home

Debere can cover a range of meanings, depending on context:

• ought to
• should
• must
• sometimes more literally to owe

Here, with a doctor speaking about the boy staying home, the most natural sense is probably ought to or should.

So eum domi manere debere is most naturally:

• that he should stay at home or
• that he ought to stay at home

Latin word order is much more flexible than English word order because Latin uses endings to show how words function.

English relies heavily on order:

• The doctor touches the boy’s forehead

Latin can move pieces around more freely because the endings already show:

• who is the subject
• what is the object
• whose forehead it is
• who is the subject of the indirect statement

In this sentence:

• Medica comes first as the subject
• frontem pueri stays together as a clear unit
• eum domi manere debere forms the indirect statement after dicit

So the order may feel unusual to an English speaker, but it is perfectly normal Latin.

Yes. Frons, frontis can mean:

• forehead
• brow
• more generally front

But in this sentence, because a doctor is touching a child and then saying he should stay home, forehead is clearly the intended meaning.

So context helps you choose the right English word.