Often the most obvious symptom of incorrect oral posture involves the muscles of the face. A dull, sluggish appearance and full, weak lips develop when muscles aren’t operating normally.
Constantly parted lips (with or without mouth breathing) also signal this disorder. A person swallowing incorrectly will often purse and tighten the muscles of the cheeks, chin and lips – a symptom known as a facial grimace. This can give the chin a knobby appearance because these muscles are being overused.
What Myofunctional Therapy
