About one in ten Australians who have lumbar X-rays has a lumbosacral transitional vertebra. In a minority of them the anatomy causes persistent low back, buttock or hip pain that is treated for years as non-specific strain. The condition is congenital, invisible and fluctuating, and it is usually diagnosed years after the symptoms begin, so the file of a person who has it looks inconsistent to anyone who does not know why. This guide sets out, for employers, human resources and return-to-work staff, claims assessors and case managers, and the lawyers and medical assessors who advise them, what the condition is in the terms a claim file uses, why the record looks the way it does, and how the condition sits within the Australian frameworks that govern work adjustments, leave, workers' compensation, motor accident claims, private health insurance waiting periods, income support and superannuation. It states what each framework provides and what follows from it, and what a medical report needs to contain to answer the question each framework asks. Every clinical statement is referenced to the published evidence and every legal statement to its source, and the notes at the end say what could and could not be verified. Written by a legal scholar who was diagnosed with the condition after forty-eight years, it is one of a series of guides on Bertolotti syndrome in Australia.