Am.J.Dis.Child.118:454, 1969 K.I. Kramer, Advancement of dermal icterus in
the jaundiced newborn.  This is the graph I've seen, I'm not sure of
validity or current up-dates.
                                        Full term               LBW
Dermal zone 1: Head and neck            4-7

Dermal zone 2: Trunk to umbilicus       5-12                    5-12

Dermal zone 3: Groin inc. upper thigh   8-16                    7-14

Dermal zone 4: Knees and elbows to
               ankles and wrists        11-18                   9-18

Dermal zone 5: Feet & hands inc.
               palms and soles          >15                     >10

FYI: I've used this in talks and have it on a "yellow" overhead!  Pat in SNJ