Spontaneous coronary artery dissection (SCAD) is an uncommon non-atherosclerotic etiology of acute coronary syndrome (ACS) characterized by the formation of a false lumen inside the arterial wall, resulting in sudden occlusion of blood flow without any trauma or intervention. The pathogenesis of SCAD is not completely understood, and the association between coronary artery anomalies and SCAD remains unclear. This case study reports a unique occurrence of non-ST-elevation myocardial infarction (NSTEMI) in a 43-year-old female patient. NSTEMI is caused by spontaneous coronary artery dissection (SCAD) that affects the posterior descending artery (PDA) in the setting of a single coronary artery. This is a very rare subtype of coronary artery anomaly, in which the right coronary artery (RCA) gives rise to the left anterior descending artery (LAD) and left circumflex artery (LCx). The patient was managed conservatively, considering the extent of myocardial involvement and the resolution of symptoms. This congenital anomaly may have been the primary predisposing factor for SCAD development. Further research is required to determine the correlation between coronary artery anomalies and SCAD.