Hypothesis: terminal transverse limb defects with "nubbins" represent a regenerative process during limb development in human fetuses.

BACKGROUND: Terminal transverse limb defects with nubbins occur in one arm at one of several levels (distal humerus, proximal forearm, wrist, and at the metacarpal-phalangeal joint in the hand). The associated nubbins contain osteocartilaginous tissue and small nails and are not associated with evidence of amnion disruption. METHODS: We present affected newborn infants whose terminal transverse limb defects are at one of these three levels: proximal forearm, elbow, or metacarpal-phalangeal joint. RESULTS: We hypothesize that the presence of residual digit-like structures reflects a regenerative process that has occurred during limb development in these infants. DISCUSSION: Only limited regeneration of digit-like structures can occur in the human fetus.

The windblown hand - diagnosis, clinical picture and pathogenesis.

The syndrome of the windblown hand deformity is a complex constellation of malformations affecting not only the head and the feet but also the hands in a quite distinct manner. In the hand, it involves congenital bilateral flexion contracture with ulnar deviation of the metacarpophalangeal joints. The thumb is characteristically adducted (reaching the palm; "thumb-in-palm deformity") with flexion of the MP joint and hyperextension of the IP joint. The etiology is basically unknown. We present two theories based on knowledge derived from the disciplines of evolution biology and embryology. We believe that the atavistic appearance of phylogenetically primitive muscle groups in conjunction with an impaired rotation of the extremities during embryological development account for this malformation syndrome.