Congenital Absence of Unilateral Zygapophyseal Joint and S1 Superior Articular Facet in An Adult Patient – A Case Report

Abstract This case report describes a rare congenital absence of the L5-S1 lumbosacral articular facet joint and S1 superior articular facet on the left side in a 17-year-old male presenting with lower back pain. Despite being asymptomatic in most cases, this anomaly was diagnosed through a CT scan, highlighting the importance of advanced imaging for accurate diagnosis. Awareness of such rare congenital defects is crucial for proper management of unexplained lower back pain.