Orbitofacial cleft number 5: radiographic, anatomical, and histologic study of a 24-week-old fetus.

Background: Orbitofacial clefts are caused by a congenital absence of midfacial tissues between the eye and the upper lip just medial to the corner of the mouth. As a whole, facial clefts occur with an incidence of 1.43 to 4.85 per 100,000 births. The exact incidence of these unusual orbital facial clefts is unknown. Only a few clinical cases and their treatment have been reported in the world literature, and no anatomical or histologic study has been presented.

Methods: The authors present a detailed anatomical and histologic study in a 24-week-old fetus with a right-side no. 5 orbitofacial cleft (according to Tessier's classification).

Results: During the anatomical dissection, it was observed that in the trigeminal Gasser ganglion on the right side there was no infraorbital branch of this nerve. Both the foramen rotundum and the infraorbital groove, where the nerve exits, were hypotrophic.

Conclusion: After embryologic analysis of their observation, the authors propose that the orbitofacial no. 5 cleft should be considered as a tissular disruption of the face secondary to damage of the terminal branches of the maxillary nerve.