EMG STUDIES OF LIP AND CHEEK ACTIVITY IN SUCKING HABITS

Pronounced lip and mentalis (perioral) muscle activity was developed d uring thumb and dummy sucking. Cheek (Buccinator) activity was less ev ident, showing light to moderate activity. Lip and cheek activity was more noticeable during dummy sucking than thumb sucking. Sucking water through a straw and swallowing produced similar functional patterns t o thumb sucking: strong lip and mentalis activity but comparatively lo w buccinator activity. Activity at rest in perioral muscles was pronou nced among thumb and dummy suckers, while buccinator activity was negl igible. Lip and cheek activity was substantially less, both at rest an d during sucking, in a control group of children who were not thumb su ckers.