Hi, In your screenshot, there is no jawbone when switch to the muscle tab. That is because the jaw bones are not assigned to Facial Bone, you can refer to this online manual to assign your bone structure correctly. https://manual.reallusion.com/3DXchange_7/ENU/Default.htm#3DXchange_7/Pipeline_7.0/04_Modify_Page/Character_Section/Mapping_Facial_Bones.htm?Highlight=facial%20bone%20mapping Thank you, Joanne