Journal of Bone and Joint Surgery
Volume 33A, No. 3. 1951.
An analysis of five cases indicates that they have one combination of manifestations in common, - pain and tenderness of the coccyx with associated tenderness in the sacral region. The tenderness was elicited with marked regularity in the mid-sacral level, lateral to the midline. It was justifiable to conclude that the tenderness arose from soft tissue structures, since it was eliminated by an injection of local anaesthetic into the sensitive areas. The only tissues which are likely to be affected by such injections are the layers of fat tissue underneath the deep fascia and, possibly, those situated superficial to the fascia. The potentialities of fat tissue as a source of noxious impulses has been demonstrated.
Additional support for this conclusion is provided in this series in which one patient was subjected to operation and the others yielded the expected results from local anaesthetisation. As a means of evaluating the influence of motion at the sacrococcygeal joint and between the segments of the coccyx, it is significant that in Case 2, a firm bony union was found between these structures. In this connection, Callander states that the whole coccyx may be ossified to the apex of the sacrum.