Fig. 9

Correlative imaging of the human fetal cochlea at GW14 illustrating the basal to apical gradient in the developmental progression of the organ of Corti (oc) along the cochlear duct. a Mid-modiolar microCT section through the whole cochlea at GW14 showing basal turn (bt), middle turn (mt) and apical turn (at) of the cochlear duct. b Corresponding mid-modiolar semi-thin section of the same specimen. The opening of the tunnel of Corti in the basal turn is well visible (see also Fig. 7e), while in the apical turn the tunnel of Corti has yet to form. Along the middle turn, the opening of the tunnel of Corti is very small. Furthermore, the developing spiral ganglion (spg) and nerve fibers (nf) can be seen. c Transmission electron microscopy of the same specimen confirmed that in the apical turn the tunnel of Corti has not yet formed. d Volume rendering of the microCT scan showing the exact position of the registered semi-thin section depicted in Fig. 9b. Scale bar (a-b) 500 μm (c) 5 μm and (d) 1 mm