Przez sztywność zakres ruchu jest mały.

Here, przez means because of / due to, not through in a literal physical sense.

So:

• przez sztywność = because of stiffness
• literal through is also possible with przez in other sentences, for example przez okno = through the window

In sentences about causes, przez is common, especially when the cause has a negative effect.

A slightly more formal alternative would be:

• z powodu sztywności = because of stiffness
• wskutek sztywności = as a result of stiffness

Good question. Przez normally takes the accusative case.

The noun sztywność is a feminine noun, and in the singular its nominative and accusative forms are the same:

• nominative: sztywność
• accusative: sztywność

So the case does change grammatically, but you do not see a different ending.

Compare that with a noun where the form does change:

• choroba = illness
• przez chorobę = because of the illness

There, the accusative ending is visible. With sztywność, it just happens to look identical.

Zakres is in the nominative singular because it is the subject of the sentence.

The basic structure is:

• zakres ruchu = range of motion
• jest mały = is small

So the whole sentence is built around:

• Zakres ruchu jest mały = The range of motion is small

Then przez sztywność adds the reason.

Because ruchu is in the genitive singular.

In Polish, when one noun describes another in an of relationship, the second noun often goes into the genitive:

• zakres ruchu = range of motion
• literally: range of movement

This is a very common pattern in Polish. Similar examples:

• koniec dnia = end of the day
• początek filmu = beginning of the film

So:

• zakres = range
• ruchu = of motion / of movement

Because mały agrees with zakres, which is a masculine singular noun.

In Polish, adjectives must agree with the noun they describe in:

• gender
• number
• case

Here:

• zakres = masculine singular
• so the adjective must be mały

It does not agree with sztywność or ruchu. It agrees only with the main noun being described, which is zakres.

In a normal full sentence, jest is the standard form.

• Zakres ruchu jest mały = The range of motion is small

Polish does use the present tense of być less often than English in some set expressions, headlines, notes, or very informal style, but in an ordinary sentence like this, jest is the natural choice.

So for a learner, the safest rule is:

• with a predicate adjective like mały, use jest in a full present-tense sentence

Polish word order is fairly flexible, but changing the order changes the focus or emphasis.

The given version:

• Przez sztywność zakres ruchu jest mały.

puts the cause first, so it emphasizes because of stiffness.

You could also say:

• Zakres ruchu jest mały przez sztywność.

That is still understandable, but it shifts the emphasis later in the sentence.

So the meaning stays similar, but the information structure changes. Polish often moves things around for emphasis more than English does.

It is grammatical and understandable, but in medical, physiotherapy, or anatomy contexts, native speakers might often choose a slightly different wording.

Common alternatives include:

• Zakres ruchu jest ograniczony przez sztywność.
• Z powodu sztywności zakres ruchu jest ograniczony.
• Przez sztywność zakres ruchu jest ograniczony.

Why? Because ograniczony = limited/restricted often sounds more natural than mały when talking about range of motion.

So:

• mały zakres ruchu is understandable
• ograniczony zakres ruchu is often more idiomatic in this context

Because Polish does not have articles like English a/an and the.

So:

• zakres ruchu can mean a range of motion, the range of motion, or simply range of motion

The exact meaning depends on context.

This is one of the big differences between English and Polish: Polish usually leaves definiteness unstated unless the context makes it clear.

A rough English-style pronunciation would be:

• Przez ≈ pshesh
• sztywność ≈ SHTIV-noshch
• zakres ≈ ZAH-kres
• ruchu ≈ ROO-hoo
• jest ≈ yest
• mały ≈ MAH-wih

So the whole sentence is roughly:

• pshesh SHTIV-noshch ZAH-kres ROO-hoo yest MAH-wih

A few helpful notes:

• sz sounds like English sh
• rz here sounds like zh/sh depending on accent and context, and in przez the whole word is often heard roughly as pshesh
• ń is a soft n
• ł sounds like English w

Not always, but very often przez + noun suggests a cause, especially one with an unwanted or unfavorable result.

For example:

• Spóźniłem się przez korki. = I was late because of traffic.
• Nie mogę spać przez hałas. = I can’t sleep because of the noise.

So in your sentence, przez sztywność fits well because stiffness is being presented as the reason for a problem.

If you want something more neutral or formal, z powodu is often a good choice.