Передпліччя між ліктем і зап’ястям.

It is understandable, but it sounds more like a short textbook definition, caption, or label than a fully natural standalone sentence.

A fuller version would be something like:

Передпліччя — це частина руки між ліктем і зап’ястям.
= The forearm is the part of the arm between the elbow and the wrist.

Or:

Передпліччя розташоване між ліктем і зап’ястям.
= The forearm is located between the elbow and the wrist.

So the given version is not wrong in a learning/chart context, but it is abbreviated.

In Ukrainian, the present-tense verb to be is often omitted, especially in simple statements, definitions, and short descriptions.

So Ukrainian can say:

Він удома. = He is at home.
Literally: He at home.

Likewise, this phrase can be understood as:

Передпліччя [є] між ліктем і зап’ястям.

That said, in this particular sentence, a fuller and more natural everyday version would often use a more specific verb such as розташоване (is located) rather than just an implied є.

It is in the nominative singular.

That is the basic dictionary form, and here it is the main word being talked about: the forearm.

Also, передпліччя is a neuter noun.

Because after the preposition між (between), Ukrainian normally uses the instrumental case.

So:

• лікоть → ліктем
• зап’ястя → зап’ястям

This is exactly the same idea as English using a different structure after certain prepositions, except in Ukrainian the noun itself changes form.

Між means between.

When it refers to being between two things, the nouns after it are usually put in the instrumental case:

• між ліктем і зап’ястям = between the elbow and the wrist
• між будинками = between the buildings
• між мною і тобою = between me and you

So in your sentence, між is the reason both body-part nouns change form.

Because the noun лікоть changes its stem in the oblique cases.

The base form is:

лікоть = elbow

But in other cases, the о disappears:

• ліктя
• ліктем

This kind of stem change is normal for some Ukrainian nouns, so it is something you gradually get used to rather than something you can always predict from English.

The apostrophe in Ukrainian is not silent punctuation. It shows that the preceding consonant is not softened and that the following я is pronounced more like ya.

So:

п’я sounds roughly like p + ya

not like a softened pia.

In зап’ястям, the apostrophe helps produce the correct pronunciation of the п’я part.

You see the same thing in words like:

• м’ясо = meat
• п’ять = five
• об’єкт = object

A rough English-friendly guide would be:

• передпліччя ≈ pe-red-PLEECH-chya
• ліктем ≈ LEEK-tem or LIK-tem
• зап’ястям ≈ za-PYAS-tyam

A few important details:

• чч in передпліччя is pronounced like a strong or lengthened ch sound.
• я often gives a ya-like sound.
• In зап’ястям, the apostrophe makes п’я sound clearly like pya.

If you are aiming for good pronunciation, it helps to listen to native audio, because English spelling cannot show Ukrainian sounds perfectly.

Yes, Ukrainian has several ways to say and:

• і
• й
• та

In this sentence, і is the most neutral and standard choice:

між ліктем і зап’ястям

You may also see та in similar sentences:

між ліктем та зап’ястям

That is also correct.
Й is often chosen mainly for smoother sound in certain phonetic environments, but і is perfectly normal here.

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

The given order:

Передпліччя між ліктем і зап’ястям.

puts the focus first on the body part being defined.

A reordered version such as:

Між ліктем і зап’ястям — передпліччя.

is possible, but it sounds more marked or stylistic. For a label, glossary, or simple definition, the original order is more natural.

Yes. If you want something that sounds more complete and natural, you would usually say one of these:

Передпліччя — це частина руки між ліктем і зап’ястям.
Передпліччя розташоване між ліктем і зап’ястям.

The short version in your example is fine for:

• a diagram
• a vocabulary card
• an anatomy label
• a very compressed definition

But in regular prose, one of the fuller versions would sound better.