La otoscopia muestra el conducto auditivo.

They are two different words:

• la otoscopia = otoscopy, the examination or procedure
• el otoscopio = otoscope, the instrument used to do it

In your sentence, the subject is the procedure/exam, so la otoscopia is the correct choice.

Otoscopia is a feminine noun in Spanish, so it takes the feminine singular article la.

This is very common with nouns ending in -a, especially technical or medical terms:

• la radiografía
• la endoscopia
• la otoscopia

Even though English otoscopy does not have grammatical gender, Spanish nouns do.

Because the subject is singular: la otoscopia.

The verb mostrar must agree with its subject:

• la otoscopia muestra = singular
• las otoscopias muestran = plural

So muestra is the third-person singular form of mostrar.

Here, muestra is a verb and means shows.

That can be confusing because muestra can also be a noun meaning sample:

• La muestra de sangre = The blood sample

But in La otoscopia muestra el conducto auditivo, it is clearly the verb:

• subject: la otoscopia
• verb: muestra
• object: el conducto auditivo

Spanish often uses the definite article more regularly than English, especially with body parts, anatomy, and specific known things.

Here, el conducto auditivo refers to a specific anatomical structure: the auditory canal / ear canal.

So el is natural and expected. In medical Spanish, naming structures with the article is very common.

Because in Spanish, descriptive adjectives usually come after the noun.

So:

• conducto = canal/duct
• auditivo = auditory

Together:

• conducto auditivo = auditory canal

This noun + adjective order is the normal pattern in Spanish:

• canal auditivo
• examen físico
• dolor abdominal

Yes. Both are possible, and both are understood in Latin American Spanish.

However, conducto auditivo often sounds a bit more technical or anatomical, while canal auditivo may feel slightly more common or less formal depending on context. In medical writing, either may appear.

You may also hear:

• conducto auditivo externo = external auditory canal
• canal auditivo = ear canal

In medical Spanish, mostrar often means show, reveal, or display findings.

So in a report, La otoscopia muestra... is very natural and means something like:

• The otoscopy shows...
• The otoscopic exam reveals...

This usage is very common in clinical descriptions.

Yes. It follows the standard Spanish order:

subject + verb + object

• La otoscopia = subject
• muestra = verb
• el conducto auditivo = direct object

This is the most neutral and natural order for a statement like this.

The sentence is grammatically correct, but in real medical context, you would often expect a more complete description, such as:

• La otoscopia muestra el conducto auditivo externo sin alteraciones.
• La otoscopia muestra un conducto auditivo normal.
• La otoscopia muestra inflamación del conducto auditivo.

That is because simply saying the otoscopy shows the auditory canal can sound a little incomplete unless the context already makes it clear what is being described.

In Latin American Spanish, it is pronounced approximately:

o-to-SKO-pya

Stress falls on sko:

• o
• tos
• co
• pia

And conducto auditivo is approximately:

kon-DUK-to aw-dee-TEE-bo

A few helpful pronunciation notes:

• c before o sounds like k
• v in auditivo is usually pronounced very similarly to b in Spanish
• Spanish vowels are usually clear and short, unlike many English vowels