Ivory Epiphysis

Ivory epiphysis refers to a uniformly dense epiphysis that can be a normal variant in the hands of children, usually in the distal phalanges and the middle phagalnx of the small finger. It is seen in up to 8% of boys and up to 4% of girls.

Ivory epiphyses can also occur in pathological states, such as growth retardation, renal osteodystrophy, type 1 trichorhinophalangeal dysplasia and Cockayne syndrome, where they may be indistinguishable from the normal variant, and in Thiemanns disease, where the proximal and middle phalanges (most commonly the middle finger) are usually involved.

This should not be confused with the ivory phalanx sign of psoriatic arthritis.

References

Castriota-Scanderbeg A and Dallapiccola B. Abnormal skeletal phenotypes: from simple signs to complex diagnoses. Springer (2005).