Underexpression of Shh leads to facial clefting and malformations of other frontonasal
and maxillary process derived facial structures, while overexpression of Shh resulted in hypertelorism (Hu & Helms, 1999).
Anterior ethmoid cells pneumatize the lacrimal bone & the frontonasal
process of the maxilla.
A zone of frontonasal
ectoderm regulates patterning and growth in the face.
(8) When a facial hemangioma occurs in a segmental distribution (typically within the midline frontonasal
region or the dermatome of a trigeminal nerve branch), work-up to assess for potential underlying PHACE (posterior fossa malformations, hemangiomas, arterial anomalies, cardiovascular anomalies, eye anomalies) syndrome should be undertaken.
A clean sheet of tracing material is placed over the original tracing, copying (1) the frontonasal
area, both hard and soft tissues with the soft tissue nose carried down to near the point where the outline of the nose starts to change directions; (2) the S-N line; and (3) the nasion-point A line [Figure 14].
Its special role has motivated imagingbased study of its size and shape to investigate the morphological correlation with various disorders, such as spastic cerebral palsy , fetal alcohol syndrome and fetal alcohol spectrum disorders , autism [4, 5], Turner syndrome [6, 7], HIV/AIDS , frontonasal
dysplasia , dyslexia , attention-deficit hyperactivity disorder (ADHD) , and Alzheimer's disease [12,13].
The cleft lip and palate defect occurs due to defect in the fusion of frontonasal
, maxillary, and mandibular processes, while the proboscis lateralis occurs as a result of displacement of the nasal placode during the formation of the nose [1, 2].
Oral clefts are among congenital malformations, which may or may not be associated with other congenital anomalies, and result from the nonclosure of frontonasal
and maxillary processes of the individual in the first days as an embryo (2), presenting an opening or rupture in the normal mouth characteristics (3).
The ANB angle is formed with the vertex at point N (nasion, the most anterior aspect of the frontonasal
suture, located by visual inspection on the tracing) and two sides respectively extending to A point (the deepest point on the contour of the premaxilla) as well as B point (the deepest point on the contour of the mandible)5.
Briefly, for ANB angle, A point presents the most concave point of the anterior maxillar base; Nasion (N) presents the most anterior point of the frontonasal
suture, while B point presents the most concave point of the anterior contour of mandibular symphysis.