Rictus

Rictus

Risus sardonicus is a highly characteristic, abnormal, sustained spasm of the facial muscles that appears to produce grinning.

The name of the condition derives from the appearance of raised eyebrows and an open "grin" - which can appear malevolent to the lay observer - displayed by those suffering from these muscle spasms.

Read more about Rictus:  Causes, In Popular Culture