The sagging rope sign is the term used to describe the radiographic appearances which sometimes occur after Perthes' disease. It is severe examples of that disease and indicates damage to the growth plate with a marked metaphysial reaction. The same appearance follows severe epiphysitis after forcible reduction of a congenitally dislocated hip, and certain rare epiphysial dysplasias. The origin and significance of the sign are discussed.

The cause of pseudarthrosis of the clavicle is obscure. Right-sidedness is an almost constant feature. We have proposed that the lesion is sometimes due to pressure upon the developing clavicle by the subclavian artery which is normally at a higher level on the right side. This may be accentuated in the presence of cervical ribs or unduly elevated first ribs, both of which we have observed in association with pseudarthrosis. We have also noted pseudarthrosis on the left side in association with dextrocardia (when the relative positions of the subclavian arteries are reversed) and in the presence of a large left cervical rib.

We have speculated upon the nature of the clavicular defect in cranio-cleido dysostosis, in which disorder the first ribs are habitually elevated. A similar mechanism may be involved.