Eustachian tube–Tensor veli palatini muscle–cranial base relationships in children and adults: An osteological study

Abstract

Objective The vector relationships between the Eustachian tube, Tensor veli palatini muscle and cranial base constrain the efficiency of middle ear pressure-regulation and are required parameters for computational modeling of Eustachian tube function. Here, those relationships were reconstructed from skulls and compared between children and adults. Method Reconstructions were made using modifications of previously described techniques for 18 child skulls aged 3–4 years and 20 adult skulls (10 females, 10 males; >18 years). Measured and calculated variables were compared between groups using a Student's t-test. Results Consistent with previous reports, certain variables for adult skulls exhibited sexual dimorphism. Between children and adults, significant differences were documented for measures of cranial base length and width; hard palate width; nasopharyngeal height, width and depth; Eustachian tube length; the maximum and minimum Tensor veli palatini muscle lengths; the angles of deviation of the Tensor veli palatini muscle from the Eustachian tube, and the surface area of the Tensor veli palatini muscle. There were no between-group differences in the angle of Eustachian tube decent from the cranial base, Eustachian tube deviation from the parasagittal plane or the lateral component of the Tensor veli palatine muscle–Eustachian tube angle. Conclusions The differences between children and adults that could account for the observed poorer Eustachian tube function in children include their shorter Eustachian tube, lesser Tensor veli palatine muscle–Eustachian tube vectors, and the lesser Tensor veli palatine muscle surface area. Other observed differences are attributable to growth and development of the craniofacial complex.