FCEM2-0347

A 7-year-old girl is brought to the Emergency Department by her father with a high temperature and pain in her ear. During the examination, you observe that the mastoid area is red and there is a soft, painful lump in the same spot. You diagnose her with acute mastoiditis, start her on intravenous antibiotics, and refer her to the ENT team on duty.
Which section of the temporal bone is affected in this situation?