Fig. 9. Distal growth plate abnormalities in radius and ulna of mice with three mutant alleles of Hoxa11 and Hoxd11. (A) Forelimb skeleton of control newborn (Hoxa11^+/+Hoxd11^+/-) stained with Alcian Blue and Alizarin Red. (B) Forelimb skeleton of Hoxa11^+/-Hoxd11^-/- newborn. (C) Hematoxylin and Eosin-stained section of 14-day-old control forelimb showing growth plate of the distal ulna. (D) Growth plate of distal ulna in 14-day-old Hoxa11^-/- Hoxd11^+/- mouse. Asterisks are adjacent to secondary ossification centers. (E) Distal growth plate of ulna in newborn (P0) control specimen. (F) Growth plate of distal ulna from a P0 Hoxa11^+/- Hoxd11^-/- mouse. Double-headed arrows demarcate proximodistal extent of growth plates. (G,H) Bright-field views of distal radius and ulna of Hoxa11^-/- Hoxd11^+/- newborn (hz, hypertrophic zone). (I) Dark-field image of G, showing hybridization with the Ihh probe. (J) Dark-field image of H, showing Pthr expression. (K) Hoxd11 expression pattern at E16.5 revealed by in situ hybridization with a ³³P-labeled probe. Transcripts are detectable adjacent to the distal end of the ulna (white bracket).