Limb skeletal phenotypes of timed conditional knockout embryos at E17.5.

<p>(A–E) forelimbs, (F–J) hindlimbs. (A, F) Wild-type, (B–E, G–J) conditional knockout embryos harvested from mothers injected with tamoxifen at E9.5 (B, G), E10.5 (C, H), E11.5 (D, I) or E12.5 (E, J). Asterisk in B indicates additional cartilage attached to radius; arrowhead indicates supernumerary digits, arrows in (A–C) marks the deltoid tuberosity, which is absent in (B). Abbreviations: c, clavicle; fe, femur; fi, fibula; h, humerus; il, ilium; is, ischium; r, radius; t, tibia; u, ulna.