Bilateral Tessier no. 7 cleft with an accessory maxilla and osseous choristoma: a case report.

Tessier no. 7 clefts are characterized by macrostomia, facial muscular diastasis and maxillary and zygomatic bone abnormalities. It is caused by a lack of ectomesenchyme formation or penetration of the maxillary and mandibular processes during the fourth and fifth weeks of development.