Preoperative contrast-enhanced CT images at emergency department. (A) Axial image shows a lobulated fluid collection beneath the scalp and temporalis muscle, with adjacent dural thickening below the suspected bony defect. (B) Axial image demonstrates cellulitis and abscess formation in the lateral pterygoid muscle. (C) Coronal image depicts the lateral pterygoid abscess extending through the lateral masticator space to involve the temporalis muscle. (D) Axial image shows bony erosion and bony defect of the right lower frontal bone.