Examining age, sex, and race characteristics of velopharyngeal structures in 4- to 9-year old children using magnetic resonance imaging

Abstract

Objective: The purpose of this study was to quantify the growth of the various craniofacial and velopharyngeal structures and examine sex and race effects.

Methods: Eight-five healthy children (53 White and 32 Black) with normal velopharyngeal anatomy between 4 and 9 years of age who met the inclusion criteria and successfully completed the MRI scans were included in the study.

Results: Developmental normative mean values for selected craniometric and velopharyngeal variables by race and sex are reported. Cranial variables (face height, nasion to sella, sella to basion, palate height, palate width) and velopharyngeal variables (levator muscle length, angle of origin, sagittal angle, velar length, velar thickness, velar knee to posterior pharyngeal wall, and posterior nasal spine to levator muscle) demonstrated a trend toward a decrease in angle measures and increase in linear measures as age increased (with the exception of PNS to levator muscle). Only hard palate width and levator muscle length showed a significant sex effect. However, two cranial and six velopharyngeal variables showed a significant race effect. The interactions between sex, race, and age were not statistically significant across all variables, with the exception of posterior nasal spine to posterior pharyngeal wall.

Conclusion: Findings established a large age and race-specific normative reference for craniometiric and velopharyngeal variables. Data reveal minimal sexual dimorphism variables used in the present study; however, significant racial effects were observed.

Keywords: MRI; craniometrics; levator veli palatine; sex differences; velopharyngeal.

Figure 1.

Visual display of the variables measured from midsagittal (a), oblique coronal (b), and coronal (c) planes. Abbreviations: nasion (N), menton (M), sella (S), basion (B), origin to origin (O-O), and NSB angle (left image) and oblique coronal angle of origin (middle image) noted by a degree symbol.

Figure 2.

Visual display of the measure of adenoid size measured as the distance (mm) between the nasopharyngeal margin of the adenoid tissue to the intersection of two reference lines-vertical line along posterior pharyngeal wall and horizontal line through palatal plane as seen on the sagittal image plane. The left image represents a 5-year-old with noticeable adenoids compared to the 9-year-old with absent adenoid mass.

Figure 3.

Visual display of the variables measured demonstrating the lack of change in the PNS to levator muscle insertion distance (noted by arrow) between a 5-year-old (left image) and 9-year-old (right image) despite the change in the sagittal angle and velar lengthening with growth.