She had a single muscle in her stomach moving.

I mean, your tongue is a single muscle, and you can move different parts of it in different direction.

He could not speak nor move a single muscle unless they willed it.

From that moment on Ytram could not speak or move a single muscle.

He stood perfectly still, not a single muscle moving.

It had been some time since he'd moved a single muscle.

The tongue is not formed by a single muscle.

It is not a single muscle, but a complex collection of muscles.

Not a single muscle revealed a clue about its owner's thoughts.

He moved not a single muscle until the flames died out against his skin.