The A–P axis is defined by the combination of overlapping HOX(A–D) expression. Neural crest is divided into four main categories along the A–P axis based on HOX gene expression: cranial, vagal, trunk and sacral. Cranial neural crest (green) is divided into the anterior most HOX negative neural crest and the posterior cranial HOX positive neural crest, expressing HOX PG (1–3). Vagal neural crest (blue) express HOX PG (3–7) genes and are located parallel to the cervical region of the spinal cord. Trunk neural crest (purple) express HOX(6–9) genes are derived adjacent to the thoracic/lumbar region of the spinal cord. Sacral neural crest (orange), derived from the most posterior part of the A–P axis, express HOX (10–13 genes). The potential of NC cells to generate distinct cell types is determined by their position along the anteroposterior (A–P) axis and the major derivatives of each subpopulation is shown in the corresponding section.