ABSTRACT
A 15-year-old obese female with a presumptive diagnosis of cellulitis of her right knee by her pediatrician presents with more pain and swelling. She has been on cephalexin for 24 hours. She is mildly febrile and her knee exam reveals an indurated, warm, and mildly swollen area over a portion of her knee. She has some pain with flexion and extension of her knee. Due to her obesity, her knees are both large and difficult to assess for an effusion. She may have worsening cellulitis with or without possible joint involvement. You perform a bedside ultrasound of her knee. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429435003/2bb12154-e53e-46cc-a47b-000836900a25/content/ufig166_1.jpg"/>
