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The frontozygomatic or Number 8 cleft is found in both Treacher Collins syndrome and the Goldenhar variant of hemifacial microsomia. Skeletal defects are more prominent in Treacher Collins syndrome, whereas the soft tissue clefting is more typical in cases of \'\'Goldenhar syndrome\'\'. Soft tissue clefting presents as a dermatocele, a true lateral eyelid coloboma with absence of the outer canthus, and anomalies of the globe itself, especially epibulbar cysts in patients with Goldenhar syndrome. The frontozygomatic bony cleft produces absence of the lateral orbital rim; this border now is formed by the hypoplastic greater wing of the sphenoid. The absence of bony support for the outer canthus produces lateral canthal dystopia and the characteristic antimongoloid slant of the palpebral fissures. Secondary to the bony deficiency in the lateral orbital wall and floor, there is soft tissue continuity between the orbit, temporal fossa, and infratemporal region. Preauricular hairline indicators delineate the Number 8 cleft as the first of the northbound clefts. Complete absence of the bony lateral orbital wall and rim constitute the skeletal element of the Number 8 cleft. The lateral border of the orbit is formed by the greater wing of the sphenoid from which small spicules of bone, which represent the rudimentary zygoma, may be found in Treacher Collins syndrome. The symmetry of the facial anomalies is reflected in the apparently normal symmetric anterior and middle cranial fossae. [PMID:2503273]
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