Figure 15-11. A, The basic arrangement of the segmental innervation (dermatomes) of the skin of the lower limb, which is supplied successively down the pre-axial border and then up the postaxial border. Note that the first toe is supplied by the fifth nerve and that the fifth toe is supplied by the first nerve. 8, An embryo of 7 weeks (measuring 17 mm between the small arrows) showing the longitudinal axes (A) of the upper and lower limbs. The parts of the limbs rostral to the axes are termed postaxial. The sequence of dermatomes from pre-axial to postaxial is shown on each limb. Cf. fig. 8-10. Click for high resolution image.