Lamellar Sectional Anatomy Of The Eustachian Tube And Its Surgical Significance

Objective:To provide lamellar sectional anatomy data for surgery of the eustachian tube and its adjacent structures, by using the continuous horizontal lamellar sectional anatomy images of pars nasalis pharyngis and lateral cranial base.Method:The digital freezing milling technique was used to obtain continuous sectional data in order to observe and measure the crosssectional images of the eustachian tube and other structures around it.15 cadaver heads (30 sides) in cornal without organic lesion were screened, then fixed, deepfreezed and embeded. They were cut as thin as 0.1 mm to obtain continuous images to measure.Results:There were totally 197 to 254 cross-sections from eustachian tube's appearance to disappearance, including 63 to 89 sections showing bony part.1. The maximal longitude of the tubal torus was (4.92+2.68)mm, which was the width of the pharyngeal opeaning of the eustachian tube. On the plane of the pharyngeal opeaning, inferior nasal concha were observed in 19 of 30 subjects and the distance between then was (11.65+3.42)mm.2. On the plane of midpiece of the eustachian tube, lateropharyngeal space was an inverted cone with big bottom and small top. Infratemporal fossa carried to formate pterygopalatine fossa upwords.3. The wall thickness between the bony part of auditory tube and carotid canal was (28±0.31)mm. Conclusion:1. The digital freezing milling technique was used to obtain continuous sectional data in order to observe and measure the crosssectional images of the eustachian tube and other structures around it, whose advantages were more accurate and clearer.2. The measure of pharyngeal opening of auditory tube demonstrated that there was individual differences in size and shape, which was usefull for disease diagnosis, such as secretory otitis media and allergic rhinitis.3. Pharyngeal recess and lateropharyngeal space both had complicated anatomic structures. There was lots of mutiple tumors here. Discerning significant anatomic structures was extremely important.4. The wall thickness between the bony part of auditory tube and carotid canal was (28±0.31)mm, which is helpful for surgery in auris media and middle cranial fossa.