During an Extraoral Examination of a Patient,which of the Following

During an extraoral examination of a patient,which of the following needs to be considered with the sternocleidomastoid muscle? (Select all that apply. )

A) If one of the muscles contracts,the head and neck bend to the contralateral side.
B) Effective palpation of the muscle occurs when the patient moves the head to the contralateral side.
C) If both muscles contract,the head will flex at the neck and extend at the junction between the neck and skull.
D) If one of the muscles contracts,the face and anterior part of the neck rotate to the ipsilateral side.