Here is the sentence in dispute:

In humans, the femoral angle shows no correlation with femoral length.

The question: why would 'femoral angle' receive a definite article, but not 'femoral length'? I feel like it does, but my co-author says no. I can't really justify it, but I feel like 'angle' somehow needs the article whereas 'length' does not.


Thanks for all the answers. Yes, I am aware the anatomy may be esoteric, and apologies for that. In this case, the angle is measured in degrees, or fractions (in decimal) of degrees. The length is similarly measured in centimeters or fractions (in decimals) of centimeters. (And there really is only one of each on a person's leg.) So while I felt like angle requires a definite article because of the way I have always seen it used, in this case I can't logically defend the difference between angle and length.

  • From the earlier question nominated: "You can use the definite article with some singular count nouns to make a generalization."
    – Andrew Leach
    Commented Oct 7, 2023 at 8:46
  • 1
    Semantically, stuff has one length, but can have multiple angles. The determiner alerts us to a situation where one is designated as the femoral angle.
    – Phil Sweet
    Commented Oct 7, 2023 at 9:36
  • 1
    It's not clear from the context if people can have multiple femoral angles or femoral lengths, or if femoral length is more general than femoral angle. Please put relevant information in the question and don't assume we all have degrees in anatomy.
    – Stuart F
    Commented Oct 7, 2023 at 9:42
  • 2
    @AndrewLeach, this question is not about using the when referring generically, but about when the the can be omitted. I believe it is not a duplicate of the suggested duplicate.
    – Peter
    Commented Oct 7, 2023 at 10:05
  • 3
    Suppose there is a table in your article that has two columns. One contains the femoral angles, the other contains femoral lengths. What are you going to put as the heading at the top of the two columns? I would put "Femoral angle" and "Femoral length". If you agree, there's the answer. The two variables are "femoral angle" and "femoral length" these are the two things that don't correlate. You could put "the" in front of either or both and still have a grammatical sentence; but to put "the" in front of angle, but not "length" is poor style, as it breaks parallelism. Commented Oct 7, 2023 at 17:58

5 Answers 5


This is a nuanced call and there is no wrong way, with or without the definite article would be fine.

The definite article, the femoral angle, establishes "femoral angle" as the primary semantic subject, and "femoral length", without article, is ancillary.

I'm not a doctor, though I sometimes play one here on ELU, and I also have the sense that the femoral angle is a more reliable indicator of some things in its own right, whereas femoral length has to be understood in relation to other facts.

FWIW, "shows no correlation with" could be simplified and in doing so any doubts about the article would go away:

In humans, femoral angle and femoral length are uncorrelated.

  • You cannot use here: In humans, femoral angle shows no correlation etc. So the question is why is that so? Because countable nouns require a determiner in English unless they are plural. That's why.
    – Lambie
    Commented Oct 7, 2023 at 16:02
  • @Lambie: Use what here?
    – TimR
    Commented Oct 7, 2023 at 16:41
  • I already wrote it: In humans, femoral angle [singular] shows etc. A singular in that position with no determiner is agrammatical in English.
    – Lambie
    Commented Oct 7, 2023 at 17:09
  • @Lambie: Is the following sentence ungrammatical? "Annual salary shows some correlation with educational level."
    – TimR
    Commented Oct 8, 2023 at 11:20
  • Or "Annual salary is related to educational level"
    – TimR
    Commented Oct 8, 2023 at 11:29

Does 'angle' as a noun necessarily receive a definite article?

All nouns may have a definite article. The definite article appears where the noun is

  1. well-known "The sun is hot"; "The weather is warm." "The people are unhappy"

  2. known to the speaker and listener "The cat is big."

  3. has been previously mentioned "A cat crossed the garden - I had seen the cat before."

  4. is defined "The green ball is big"; "The ball that is green is big."

Here is the sentence in dispute: In humans, the femoral angle shows no correlation with femoral length.

In your sentence, In humans, the femoral angle shows no correlation with femoral length, angle is defined - femoral- it therefore may take the definite article. It is also countable and therefore must have an article/determiner of some sort.

Length is also countable and defined and therefore must also have a definite article: it has, the "the" does double duty - it is a determiner to both femoral angle and femoral length.

Compare "The cat and dog played happily". The car and lorry both swerved" in which the modifies both nouns.

  • 1
    I don't think that length in OP's usage is countable. Commented Oct 7, 2023 at 15:33
  • You write: "The weather is warm." "The people are unhappy" //I write this: Weather is difficult to predict. People can be annoying. The fact angle is defined is not relevant. You can't say: Femoral angle shows no correlation with femoral length **unless you are using technical shorthand.
    – Lambie
    Commented Oct 7, 2023 at 15:49
  • 'All nouns may have a definite article.' Some nouns, especially some proper names, strongly resist countification. ??'The Boötes' Commented Oct 7, 2023 at 18:00
  • @Araucaria-Him - I suggest putting "much" and "many" before "length" - many is diagnostic of countability.
    – Greybeard
    Commented Oct 8, 2023 at 9:02
  • @EdwinAshworth Strongly resist is not the same as "cannot be". As it happens, "Boötes" was the name of a vessel that I knew: "The Boötes left port three days ago".
    – Greybeard
    Commented Oct 8, 2023 at 9:08

The word 'angle' itself is rarely used outside of determiner phrases. A Google search for

  • "angle is usually measured" -"the angle" -"an angle" -"vertical angle"

yields only 11 000 raw hits, with few anarthrous tokens (ignoring hits with other determiners, 'which/this ... angle')

The hits include some relevant examples (not all containing the whole search string):

  • Practical Contact Angle Measurement [but this in a heading, so inconclusive]
  • What is angle measured in?
  • phase angle
  • spraying angle
  • rake angle

Collins gives 'variable' and 'uncountable' categorisations for the relevant subsenses of 'length', but does not register the corresponding noncount usage/s of 'angle'.

But in examples like

  • Last term in geometry class 1c looked briefly at measuring length, which the students should all have been familiar with from junior school. This term they will look at the measurement of angle, which may be new to some of them.
  • ... a short description of the common angles and the methods of angle measurement. ...

      [I]t is important for [pupils] to note that this degree is the unit measurement of angle.                   [Vedantu; amended slightly]

the noncount usage does occur†. But it's rare, and largely domain-specific, and one would probably see 'the femoral angle' rather than the anarthrous variant. But this is driven by usage rather than strict logic / patterning.

†The postmodified word can also occur without further specification:

  • Angle DÊF is acute

but this is hardly the same situation; 'the' could also be used before 'angle' here. The attributive usage, see 'angle measurement' above, is also subtly different.


The mixture in OP's example sounds unbalanced; '... the length of the femur' is perhaps a happier choice here.

  • Examples of determiner less nouns in coordinations such as length and angle do not count for anything because they are examples of bare coordination Commented Oct 7, 2023 at 15:55
  • @Araucaria-Him What is "a determiner less nouns? Do you mean: a noun less a determiner? //Edwin, Why Google search "angle is usually measured" ? It isn't even grammatical. However, the plural is: Angles are usually measured by x.
    – Lambie
    Commented Oct 7, 2023 at 16:16
  • @Lambie Typo: "determinerless" Commented Oct 7, 2023 at 16:22
  • @Araucaria-Him Okay.
    – Lambie
    Commented Oct 7, 2023 at 17:09
  • I'd say there's a big difference between the examples given in CGEL, which are largely fixed phrases ['[both] x and y at the same time' and irreversible (??"Are you mouse or man?" *'wife and man'), and more general coordinations. However, I've tweaked the example. Commented Oct 7, 2023 at 18:29

Unless you have an uncountable noun like coffee or tea or a mass noun, English always requires the determinative a or the, or a plural word. Edit: or some other determiner.

You cannot just start out with femoral angle without one of those. So, you can use "the" as used in formal writing: The tiger is a noble beast. The atom was first split in x.

Length can be a complicated measure to ascertain in some cases. Measurements are considered mass nouns and do not require a determinative per se.

List of common mass nouns in English.

  • 4
    "Measurements are considered mass nouns and do not require a determinative per se": why is it that length is a measurement but angle is not?
    – phoog
    Commented Oct 7, 2023 at 1:02
  • 1
    But in the phrase my dog, there is no a or the and there is no plural word. Commented Oct 7, 2023 at 12:24
  • 1
    Araucaria's angle on that dog is another takeaway. How many dets modify singular nouns? Can you broaden the examples or include the PS meaning of determiners?
    – livresque
    Commented Oct 7, 2023 at 12:42
  • 'Angle' is used in the non-count incarnation (I used to teach maths), but rarely, especially outside maths contexts. It seems a very special case. Commented Oct 7, 2023 at 13:20
  • @Araucaria Count usages with singular-form nouns need articles or other determiners (or the unique numeral 'one'). The/a dog // my/this/every ...dog // one dog. Commented Oct 7, 2023 at 13:23

It is correct to leave out the in the original sentence.

Merriam-Webster provides the following sample sentence:

Brain size is correlated with intelligence.

Applying this to your sentence would give

Femoral angle is not correlated with femoral length.

Adding In humans does not change the correctness of this form. Neither does changing is not correlated with to shows no correlation with.

As a matter of style you might use the same form for both measurements:

In humans the femoral angle is not correlated with the femoral length.

It is not necessary though, as the femoral angle is the subject and femoral length is the object.

I find the version with the twice the most natural, though I have seen similar sentences with the omitted in both places. To me this latter version seems more formal.

A possible reason for omitting the articles lies in the statement in Lambie's answer, that

Measurements are considered mass nouns and do not require a determinative per se.

(Summarised from mass nouns where measurements are classed under Abstract concepts)

As correlation, in its usual sense, is about the relationship between mathematical variables or data values, the femoral angle and the femoral length must both be understood to be measurements, not merely the things measured. This means both are treated as mass nouns and so the (or something else) is not automatically needed.

  • This whole post makes the dire mistake of using a conjecture from another post as the correct basis for working out an answer.The point about angle is that it is countable in its usual sense , whereas length in the sense used is not. In addition, definite articles are used with readily identifiable named things which every person or building or shape etc has (e.g. the roof, the hypotenuse, the heart. The femoral-tibial angle is one of those named, readily identifiable things. Femoral length, in contrast, is not. Commented Oct 7, 2023 at 14:43
  • No, angle is not a measurement.
    – Lambie
    Commented Oct 7, 2023 at 18:13
  • @Araucaria-Him, I am puzzled why angle is not readily understood as a measurement, especially in OP’s context. We routinely speak of 60 degree angles, just as we speak of 60 centimetre lengths. Further, the word “correlation” makes no sense to me unless the angle and the length are both numerical quantities.
    – Peter
    Commented Oct 8, 2023 at 1:59
  • Is that a comment for Lambie, perhaps? It's doesn't matter whether they happen to measured or not. The femoral-tibial angle has a definite article, because a) it has a name b) everybody's leg has one. It's like saying the ankle. Whether something is a measured dimension or not doesn't make any difference as to whether we need to use a definite article with it! Commented Oct 8, 2023 at 9:50
  • 1
    @Lambie, femoral angle must be a measurement for there to be any possibility of a correlation with femoral length.
    – Peter
    Commented Oct 8, 2023 at 10:58

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