Which of the muscles show least EMG activity, when mandible is in centric relation?
The anatomic attachments of posterior and middle parts of temporalis, masseter and medial pterygoid muscle are actively involved in holding mandible in its centric relation. Most relaxed muscle out of given options is lateral pterygoid muscle and hence it will show least EMG activity.
Posterior fibres of temporalis
Middle fibres of temporalis
Medial pterygoid muscle
Lateral pterygoid muscle