يظهر تسوس الأسنان في صورة الأشعة السينية.

يظهر is a verb meaning appears, shows up, or becomes visible.

In this sentence, it means that the tooth decay appears/is visible in the X-ray image.

• ظهر = he appeared / it appeared
• يظهر = he appears / it appears

Arabic often starts sentences with the verb, so beginning with يظهر is very normal.

Because the subject here is تسوس الأسنان (tooth decay), and تسوس is grammatically masculine singular.

So the verb agrees with تسوس, not with الأسنان.

• تسوس = decay / caries
• الأسنان = the teeth

Even though teeth is plural, the head noun of the phrase is تسوس, so the verb is singular masculine:

• يظهر تسوس الأسنان = Tooth decay appears

If the subject were a feminine singular noun, then you would expect تظهر.

The subject is تسوس الأسنان.

More specifically:

• يظهر = the verb
• تسوس الأسنان = the subject
• في صورة الأشعة السينية = a prepositional phrase meaning in the X-ray image

In a verbal sentence in Arabic, the subject often comes after the verb, unlike normal English word order.

So literally the structure is:

• appears
  • tooth decay
    • in the X-ray image

تسوس الأسنان literally means decay of the teeth, which is the natural Arabic way to say tooth decay or dental caries.

This is an iḍāfa construction (genitive/possessive construction):

• تسوس = decay
• الأسنان = the teeth

Together:

• تسوس الأسنان = the decay of the teeth / tooth decay

In an iḍāfa:

1. the first noun usually does not take ال
2. the second noun can be definite and makes the whole phrase definite if it is definite

So تسوس الأسنان is a very standard structure.

Because it is the first term of an iḍāfa.

In Arabic, the first noun in an iḍāfa normally does not take ال, even when the whole phrase is definite.

Compare:

• كتاب الطالب = the student’s book
• تسوس الأسنان = tooth decay / the decay of the teeth

So تسوس is left without ال, and definiteness comes from الأسنان.

في usually means in.

Here it introduces the location or medium where something is seen:

• في صورة الأشعة السينية = in the X-ray image

So the sentence is saying that the tooth decay is visible in that image.

It means the image of the X-rays, or more naturally in English, the X-ray image / the X-ray.

This is another iḍāfa:

• صورة = image, picture
• الأشعة السينية = the X-rays / X-ray radiation

So:

• صورة الأشعة السينية = the X-ray image

Depending on context, English may translate it simply as on the X-ray.

الأشعة is the plural of شعاع, meaning ray.
So الأشعة = the rays.

السينية is the adjective meaning X-ray, literally related to the letter س (sīn), which was historically used to represent X.

So:

• الأشعة السينية = X-rays

The adjective السينية agrees with الأشعة in definiteness, gender, and number as Arabic normally requires.

This is a very common point for learners.

الأشعة is a non-human plural. In Arabic, non-human plurals are very often treated grammatically like feminine singular when adjectives refer to them.

So:

• الأشعة = plural in meaning
• but the adjective is often feminine singular
• therefore: الأشعة السينية

This is normal Arabic agreement.

The same pattern appears in many other examples:

• الكتب الجديدة = the new books
• السيارات السريعة = the fast cars

Even though books and cars are plural, the adjective often appears in the feminine singular form in standard agreement with non-human plurals.

It is definite.

Why? Because it is an iḍāfa, and the second part is definite:

• الأشعة has ال
• السينية also has ال

So the whole phrase becomes definite:

• صورة الأشعة السينية = the X-ray image

Even though صورة itself does not have ال, the whole expression is definite because of the iḍāfa structure.

It could, depending on context, but the sentence as written uses:

• في صورة الأشعة السينية

This means something like in the X-ray image or in an X-ray image, depending on how the phrase is understood in context.

Because صورة is in iḍāfa with الأشعة السينية, the phrase is already a complete noun phrase. Arabic often does not need an extra ال on the first noun in this structure.

If someone said في الصورة, that would simply mean in the picture/image, which is less specific unless the context already makes it clear that the image is an X-ray.

It is a verbal sentence (جملة فعلية) because it begins with a verb:

• يظهر = verb
• تسوس الأسنان = subject
• في صورة الأشعة السينية = prepositional phrase

Arabic has two major common sentence types:

1. Verbal sentence: starts with a verb
2. Nominal sentence: starts with a noun

So this sentence is verbal because the action/state of appearing is presented first.

Yes. A possible alternative is:

• تسوس الأسنان يظهر في صورة الأشعة السينية.

This puts the subject first:

• تسوس الأسنان = tooth decay
• يظهر = appears

Both are possible, but the original version with the verb first is very natural in Arabic.

There can be slight differences in style or emphasis:

• يظهر تسوس الأسنان... = more straightforward verbal flow
• تسوس الأسنان يظهر... = slightly more emphasis on tooth decay

A careful pronunciation would be roughly:

yaẓharu tasawwusu al-asnān fī ṣūrati al-ashiʿati as-sīniyya

A few notes:

• يظهر = yaẓharu
• تسوس = tasawwus
• الأسنان = al-asnān
• صورة = ṣūra
• الأشعة = al-ashiʿa
• السينية = as-sīniyya

In pausa (normal spoken reading), final case vowels are often dropped, so learners may hear something closer to:

yaẓhar tasawwus al-asnān fī ṣūrat al-ashiʿa as-sīniyya

In fully vocalized formal Arabic, yes, they show grammatical case and mood. For example, in very careful reading you might see forms like:

• يظهرُ
• تسوسُ
• صورةِ
• الأشعةِ
• السينيةِ

But in most everyday pronunciation of Modern Standard Arabic, speakers often pause or read without fully pronouncing all final case endings.

So for learners:

• it is useful to know they exist
• but it is also normal to hear them reduced or omitted in actual speech

Yes. تسوس is a verbal noun-like form referring to the condition or process of decaying, especially in a medical or dental context.

So instead of saying something like the teeth decay, Arabic can use the noun:

• تسوس الأسنان = tooth decay

This is very common in Arabic, especially in formal, scientific, or medical language.

Yes, it sounds quite formal and natural for medical, educational, or scientific Modern Standard Arabic.

Words and structures like:

• تسوس الأسنان
• الأشعة السينية
• verb-first order

all fit well in formal written or spoken MSA, especially in textbooks, reports, or explanations by a doctor.