There is a soft tissue cleft medial to the inner canthus with a cleft of the root of the eyebrow. The frontal process of the maxilla is flat and broadened, and the ethmoid labyrinth is increased in tranverse dimension, thereby producing orbital hypertelorism. The cribriform plate is of normal width. The frontal sinus is enlarged. Even though the frontal bone is flattened, bony clefts with encephalocele have not been observed. There is a lateral displacement of the inner canthus with a mild thinning, aplasia, or irregularity of the medial end of the eyebrow. There are no eyelid clefts. The soft tissue contour of the forehead is normal, with only a short downward prolongation of the paramedian frontal hairline to mark the superior extent of the soft tissue cleft. Flattening of the frontal process of the maxilla, an increase in the transverse dimension of the ethmoid sinus, and a laterally convex bowing of the medial orbital wall produce orbital hypertelorism. Superiorly there is a minor flattening of the frontal bone medially, and the nasofrontal angle is somewhat obtuse. The extensive pneumatization of the sinuses on the cleft side extends backward through the frontal and ethmoid sinuses and into the sphenoid sinus. The anatomy of the sphenoid, including the pterygoid processes, is otherwise normal. The anterior and middle cranial fossae floors are both broadened on the cleft side with minor widening of the cribriform plate. [from
HPO]