There is plenty of general material to be found on the racial policies of Nazi Germany in education, such as in Facing History and Ourselves
Schooling for the National Community
History and science were the subjects most influenced by Nazi ideology. Soon after Hitler took power, a new course in “race science” was added to the curriculum in every German school. The Nazi minister of education outlined the objectives of the course...
Racial instruction was not limited to a single course. It was included in all classes, even arithmetic.
More specific to phrenology are these references:
Spartacus Educational states in
Education in Nazi Germany
Changes to the School Curriculum
Hitler immediately made changes to the school curriculum. Education in "racial awareness" began at school and children were constantly reminded of their racial duties to the "national community". Biology, along with political education, became compulsory. Children learnt about "worthy" and "unworthy" races, about breeding and hereditary disease. "They measured their heads with tape measures, checked the colour of their eyes and texture of their hair against charts of Aryan or Nordic types, and constructed their own family trees to establish their biological, not historical, ancestry.... They also expanded on the racial inferiority of the Jews".
This is footnoted to the book Nazi Women by By Cate Haste page 101.
In his autobiography, A Childhood under the Nazis (1998), Tomi Ungerer commented that one of the textbooks that he was forced to use was the anti-Semitic book, The Jewish Question in Education, which contained guidelines for the "identification" of Jews (13). Written by Fritz Fink, with an introduction by Julius Streicher it included passages such as the "Jews have different noses, ears, lips, chins and different faces than Germans" and "they walk differently, have flat feet... their arms are longer and they speak differently."