MedGen

The temporozygomatic Number 7 cleft is found in both Treacher Collins syndrome and hemifacial microsomia. Soft tissue manifestations include macrostomia, malformations of the external and middle ear, temporalis muscle, variable involvement of the seventh cranial nerve (in hemifacial microsomia), and abnormalities of the preauricular hair in Treacher Collins syndrome. The skeletal cleft is through the pterygomaxillary junction, and vertical maxillary hypoplasia is present. In addition, abnormality of the mandibular ramus, coronoid, and condyle and absence of the zygomatic arch are typically present. A soft tissue furrow extends from the macrostomia laterally and superiorly across the cheek toward the preauricular hairline. The lower eyelids are intact. The anatomy of the external ear is normal, and there are no preauricular tags. Bony clefting is through the pterygomaxillary junction with hypoplasia of the alveolar process in the molar region, thereby producing a posterior open bite. The maxilla is hypoplastic, although the maxillary sinuses are symmetrically pneumatized. The hypoplastic zygomatic body arches upward, but then it takes a downward course and is severely malformed and displaced. The zygoma is continuous posteriorly with an apparently normal zygomatic process of the temporal bone. The mandibular condyle and coronoid process are hypoplastic and asymmetric. There is no antegonial notching of the mandible. Marked cranial base asymmetry, with tilting and asymmetric positioning of the temporomandibular articulations, is present. The anatomy of the sphenoid is abnormal, especially on the right where there is no recognizable medial or lateral pterygoid plate. [from HPO]

In a Number 10 Tessier cleft there is an upper central orbital cleft with a cleft of the middle one-third of the upper eyelid, which often results in total ablepharia. The eyebrow is disrupted, being virtually absent medially, whereas the lateral portion angles upward toward the frontal hairline. There may be ocular anomalies, including colobomata of the iris. The skeletal cleft is through the midportion of the supraorbital rim, the adjacent frontal bone, and the orbital roof lateral to the supraorbital nerve. A frontal encephalocele frequently occupies the frontal bony cleft. The palpebral fissure is grossly elongated with an amblyopic eye displaced inferiorly and laterally. There is also a divergent squint of the right eye. The eyebrow is deficient medially and becomes thinned out laterally , where it is contiguous with a broad downward and forward projection of the frontotemporal hairline (this may be seen in both the Number 9 and 10 clefts.) A broad frontal encephalocele bulges forward from the middle one-third of the right forehead, supraorbital ridge, and orbital roof. The bony cleft, through which the frontal encephalocele presents, involves the anterior half of the orbital roof, the supraorbital rim, and two-thirds of the vertical height of the frontal bone lateral to the supraorbital nerve. The bony orbit is inferiorly displaced and widened with the lateral orbital wall shortened and laterally deviated. Similar distortion of the anterior cranial fossa is evident, being broader and more flattened on the affected side. The calvarium above the level of the cleft and the cranial base below is symmetric. [from HPO]