Pain caused by the sacroiliac joint (SIG) makes up a relevant proportion of lumbar back pain and can have a variety of specific and non-specific causes. The SIG represents the central link between the spine and the lower extremity. It is characterized by high stability and low mobility. There are significant inter-individual differences. In addition to the possibility of asymptomatic situations, SIG dysfunction can trigger pain in the lower back with possible radiation to the lower extremity. In addition to a structured medical history, clinical examination requires an examination of the adjacent joints and the neurological status. More specifically, movement and provocation tests as well as infiltrations are carried out. General information and conservative therapeutic methods represent the first-line therapies. Interventional and surgical procedures can help in the case of chronification.