has part has part has_part characteristic of has modifier absent pharyngeal arches abnormal second pharyngeal arch morphology absent second pharyngeal arch absent second branchial arch MPheno.ontology MP:0006345 absence of the structure of the second arch which contributes to the development of the stapes, styloid process, hyoid bone, stylohyoid ligament, muscles of facial expression, stapedius muscle, stylohyoid muscle, and lining of the palatine tonsils abnormal absent pharyngeal arch 2