Normal CT Manifestations Of Hypopharynx In Adults

Objective To approach the normal manifestations of the hypopharynges of the adults as seen on computed tomographic (CT) images, and to evaluate their clinical value. Methods Eighty-four CT images of the normal hypopharynges were reviewed. The hypopharynx was divided into three regions:①the piriform sinus,②the retropharynx area,③the postcricoid region .The postcricoid region of hypopharynx was subdivided into three levels as follows:①the upper margin slice of the cricoid cartilage at the cricoarytenoid joint level,②the middle portion slice of the cricoid cartilage, and③the inferior margin slice of the cricoid cartilage. The anteroposterior and transverse diameters, and anterior and posterior wall thicknesses in the postcricoid region were measured. Depiction of The layers of the musculature and adjacent fat planes was evaluated. The piriform sinuses were observed in 7 cases who performed Valsalva breath. Results At the upper cricoid slice level, the anteroposterior and transverse diameters, and the anterior and posterior wall thicknesses ((?)±S) in the postcricoid region were 4.92±0.98mm, 36.95±3.66mm, 1.99±0.49mm, 2.89±0.56mm respectively; at the middle portion slice of the cricoid cartilage, they were 5.43±0.98mm, 31.77±4.04mm, 2.23±0.50mm, 3.15±0.54mm respectively and at the lower cricoid slice level, they were 5.84±0.98mm, 26.78±3.60mm, 2.43±0.48mm, 3.36±0.53mm respectively. The posterior wall tended to be 1mm thicker than the anterior wall. There were no statistically significant differences related to sex or age. The transverse extension of the postcricoid musculature was an average of 4.5mm shorter in female than in male at CT images. The transverse diameter tended to taper about 10mm from the upper cricoid slice level to the lower cricoid slice level. Demonstration of the intramural fat planes of the postcricoid region decreased from the upper(80.95%) to the lower region(23.80%) of the cricoid cartilage. In fat planes around the postcricoid region at all levels, the posterior fat plane was seen least frequently, and the left-sided fat plane was seen most frequently. The piriform sinus are similar to circular. The sizes are similar bilaterally and the appearances are symmetry bilaterally on the whole. Valsalva breath can display the appearance of the piriform sinus well. Conclusion Knowledge of the normal appearances and variations of the hypopharynx is essential in detecting abnormalities in this area.