Research progress in evaluating velopharyngeal structures and functions by magnetic resonance imaging / 口腔疾病防治

@#Normal development of the velopharyngeal structures is key to obtaining good velopharyngeal closure. In the assessment of velopharyngeal closure and normal pronunciation, a variety of instruments can be used to detect and assist in the diagnosis of velopharyngeal dysfunction. In the past, the assessment of velopharyngeal closure often used two-dimensional imaging or relied solely on the subjective assessment of the phonetician. With the development of science and technology, magnetic resonance imaging (MRI) has become widely used in the evaluation of velopharyngeal structures and functions as an ideal examination method. This article reviews the current capabilities and limitations in evaluating velopharyngeal closure, as well as recent research on the structures and functions of the velopharyngeal using static MRI, dynamic MRI, three-dimensional MRI reconstructions and diffusion tensor imaging (DTI) techniques; in addition, this work explores the role and significance of MRI technology in evaluating the structures and functions of the velopharyngeal. A review of the literature shows that static MRI is simple in terms of the scanning mode, has easily adjustable parameters, and clearly shows the anatomical structures of palatopharyngeal in resting or transient vocal states. Dynamic MRI can capture the anatomical changes of the palatopharyngeal in a more complex pronunciation state and obtain accurate dynamic images of the velopharyngeal closure process for the study of speech pathology. Three-dimensional MRI reconstructions are usually used in fine scanning of the velopharyngeal structures in a resting state; although this method takes a long time, the images obtained are clear and reliable. This approach can be used for three-dimensional reconstruction analysis and three-dimensional finite element analysis, and it can be used to help plan an operation and evaluate the effect of the surgery. DTI is a new method for observing the contractile function of muscles by observing the locus of water molecules in muscles. DTI can be used to analyze and study many muscles involved in velopharyngeal closure.

Fetal anatomy of the upper pharyngeal muscles with special reference to the nerve supply: is it an enteric plexus or simply an intramuscular nerve? / 대한해부학회지

We examined pharyngeal nerve courses in paraffin-embedded sagittal sections from 10 human fetuses, at 25-35 weeks of gestation, by using S100 protein immunohistochemical analysis. After diverging from the glossopharyngeal and vagus nerves at the level of the hyoid bone, the pharyngeal nerves entered the constrictor pharyngis medius muscle, then turned upward and ran superiorly and medially through the constrictor pharyngis superior muscle, to reach either the levator veli palatini muscle or the palatopharyngeus muscle. None of the nerves showed a tendency to run along the posterior surface of the pharyngeal muscles. Therefore, the pharyngeal nerve plexus in adults may become established by exposure of the fetal intramuscular nerves to the posterior aspect of the pharyngeal wall because of muscle degeneration and the subsequent rearrangement of the topographical relationship between the muscles that occurs after birth.

Initial stage of fetal development of the pharyngotympanic tube cartilage with special reference to muscle attachments to the tube / 대한해부학회지

Fetal development of the cartilage of the pharyngotympanic tube (PTT) is characterized by its late start. We examined semiserial histological sections of 20 human fetuses at 14-18 weeks of gestation. As controls, we also observed sections of 5 large fetuses at around 30 weeks. At and around 14 weeks, the tubal cartilage first appeared in the posterior side of the pharyngeal opening of the PTT. The levator veli palatini muscle used a mucosal fold containing the initial cartilage for its downward path to the palate. Moreover, the cartilage is a limited hard attachment for the muscle. Therefore, the PTT and its cartilage seemed to play a critical role in early development of levator veli muscle. In contrast, the cartilage developed so that it extended laterally, along a fascia-like structure that connected with the tensor tympani muscle. This muscle appeared to exert mechanical stress on the initial cartilage. The internal carotid artery was exposed to a loose tissue facing the tubal cartilage. In large fetuses, this loose tissue was occupied by an inferior extension of the temporal bone to cover the artery. This later-developing anterior wall of the carotid canal provided the final bony origin of the levator veli palatini muscle. The tubal cartilage seemed to determine the anterior and inferior margins of the canal. Consequently, the tubal cartilage development seemed to be accelerated by a surrounding muscle, and conversely, the cartilage was likely to determine the other muscular and bony structures.

Ultrastructural study of the levator veli palatint muscle in cleft palate patients