Is yawning a voluntary use of muscle?

Answer 1

The muscles that are used in the process of smiling are the face muscles. There are twelve muscles that help the face to smile, a couple of them are, the Zygomaticus major and minor and the Levator anguli oris. There are of course 9 more that are included in the smile process.

It is not clear exactly how many muscles are used when smiling. Some of the muscles used for smiling are the levator anguli oris, the levator labii superioris, the orbicularis oculi, the risorius, the zygomaticus major and minor.

Answer 2

Can you force yourself to yawn, like you can choose to lift your arm or raise your leg? No, because one of the primary muscles used when you yawn is your diaphragm. The diaphragm is an involuntary muscle.

You also use your abdominal muscles when you yawn, which are skeletal (voluntary) muscles. You can use them to twist your trunk.

You can control the rate of your breathing, and you can choose to hold your breath for a certain length of time. These are semi-voluntary uses of the diaphragm. But you will always start to breathe again.

Your diaphragm also spasms when you hiccup. Is that voluntary? Everyone would agree that hiccuping is involuntary.

So, since it's the same muscle primarily involved in yawning as in hiccuping and breathing, which are both involuntary, doesn't it follow that yawning also is an involuntary use of muscle?

Yes you can suppress a yawn, but not with perfect success. And you can't make yourself yawn any more than you can make yourself hiccup.

So I say yawning is, for the most part, an involuntary use of muscle.

Answer 3

sternocleidomastoid and trapezius

Answer 4

zygomaticus major and minor

Answer 5

Zygomaticus