| Namespace | MPheno.ontology | Obsolete | false |
| description | any structural anomaly of the transient lens-shaped thickening of surface ectoderm that will give rise to the mammary bud proper; in mouse, five pairs of symmetrically positioned mammary placodes (three thoracic and two inguinal) form at reproducible locations along the mammary line at E11.5; the individual pairs develop asynchronously and in a distinct order; pair 3 is first, followed by pair 4, then by pairs 1 and 5 (which develop together), and finally by pair 2; the orientation of placodal cells is not uniform, suggesting that placodes are formed by migration of cells from the mammary line; between E11.5 and E12.5, each mammary placode expands and invaginates into the underlying mesenchyme to form an early bulb-shaped mammary bud |
