Is it "le" or "les" when translating "the biceps/triceps"?

Question

From the dictionary, it looks like biceps and triceps get the "le" since they're masculine:

• https://www.collinsdictionary.com/us/dictionary/english-french/triceps
• https://www.collinsdictionary.com/us/dictionary/english-french/biceps

But sometimes they are referred to as plural:

• https://www.ericfavre.com/lifestyle/anatomie-les-biceps/

and sometimes singular:

• https://www.dravelnutrition.fr/blog/exercice-musculation/le-top-5-des-meilleurs-exercices-biceps-pour-des-bras-muscle

In cases where we need to translate the biceps, is it both acceptable to translate it into les/le biceps since the plurality is ambiguous? e.g.

English	French	Singular / Plural
the left and right biceps	les biceps gauche et droit	PL
the left biceps	le biceps gauche	SG
the right biceps	le biceps droit	SG
the biceps	les biceps / le biceps	PL / SG

Answer 1

When talking about these muscles in general, the singular is more common than the plural:

Le biceps est un muscle du membre supérieur fléchisseur qui provoque le rapprochement de l'avant-bras vers le bras. Wikipedia

but it's not forbidden to write:

Les biceps sont des muscles des membres supérieurs fléchisseurs qui provoquent le rapprochement des avant-bras vers les bras.

I guess that would be similar in English ("The biceps is..." / "The biceps are...")

However, as soon as more than one actual muscle is involved, you need to use the plural:

Ils « poussent de la fonte » pour se muscler les biceps. (not "le" biceps).