Figure 2.
Flat-mount view of the HH21 chick rhombencephalon illustrating its early segmentation into 8 rhombomeres (r1-r8). The hox code specific for each rhombomere or odd- and even-numbered pair of rhombomeres is indicated by a color code. The different cranial motornuclei and nerve root are also represented. Abbreviations: IV, trochlear nucleus; V, trigeminal nucleus; VI, abducens nucleus; VII, facial nucleus; IX, glossopharyngeal nucleus; X, vagus nucleus; XII, hypoglossus nucleus; MHB midbrain hindbrain boundary; Mes, mesencephalon; FP, floorplate. Adapted from Kiecker and Lumsden, 2005.