This case study describes the events surrounding a series of diagnostic errors in a patient initially treated for pharyngitis and ultimately diagnosed with an epidural abscess and osteomyelitis. While reviewing the details of the case, the author explores the pitfalls leading to missed diagnoses, including several types of "cognitive shortcuts" that commonly lead to such errors. Discussion offers strategies to overcome these diagnostic shortcomings and methods to combat natural cognitive tendencies. This article is part of a special collection entitled “Quality Grand Rounds,” a series of articles published in the Annals of Internal Medicine that explores a range of quality issues and medical errors.