BackgroundBoth the advancement of visual techniques and intensive progress in perinatal medicine result in performing airway management in the fetus and neonate affected by life-threatening malformations. This study aimed to examine the 3 tracheo-bronchial angles, including the right and left bronchial angles, and the interbronchial angle, in the fetus at various gestational ages.Material/MethodsUsing methods of anatomical dissection, digital image analysis with an adequate program (NIS-Elements BR 3.0, Nikon), and statistics, values of the two bronchial angles and their sum as the interbronchial angle were semi-automatically measured in 73 human fetuses at the age of 14–25 weeks, derived from spontaneous abortions and stillbirths.ResultsNo male-female differences between the parameters studied were found. The 3 fetal tracheo-bronchial angles were found to be independent of age. The right bronchial angle ranged from 11.4° to 41.8°, and averaged 26.9±7.0° for the whole analyzed sample. The values of left bronchial angle varied from 24.8° to 64.8°, with the overall mean of 46.2±8.0°. As a consequence, the interbronchial angle totalled 36.2–96.6°, and averaged 73.1±12.7°.ConclusionsThe tracheo-bronchial angles change independently of sex and fetal age. The left bronchial angle is wider than the right one. Values of the 3 tracheo-bronchial angles are unpredictable since their regression curves of best fit with relation to fetal age cannot be modelled. Both of the 2 bronchial angles and the interbronchial angle are of great relevance in the location of inhaled foreign bodies, and in the diagnosis cardiac diseases and mediastinal abnormalities.

IntroductionTracheal wall thickness is a substantial indicator in various pathological changes. The present study was performed to compile normative data and formulae for the tracheal wall thickness and volume at varying gestational age.Material and methodsUsing anatomical dissection, digital image analysis and statistics a range of the wall thickness, proximal internal-to-external cross-sectional area ratio, and wall volume for the trachea in 73 spontaneously aborted human fetuses aged 14-25 weeks was examined.ResultsNo significant male-female differences were found. The values of tracheal wall thickness ranged from 0.36 ±0.01 mm for the 14-week group to 1.23 ±0.17 mm for the 25-week group of gestation, according to the linear function y = –0.823 + 0.083 × age ± 0.087. The tracheal lumen rate, expressed as the proximal internal-to-external cross-sectional area ratio, decreased from 42.61 ±1.11% to 26.78 ±4.95%, according to the function y = 62.239 – 1.487 × age ±3.119. The tracheal wall volume rose from 16.28 ±4.18 mm3 in fetuses aged 14 weeks to 269.22 ±29.26 mm3 in fetuses aged 25 weeks, according to the quintic function y = 0.000052 × age4.894.ConclusionsThe tracheal wall parameters show no sexual dimorphism. The tracheal wall grows linearly in its length, and according to a quintic function in its volume. A relative decrease in the tracheal lumen at the expense of an increase in both the wall thickness and wall volume of the trachea is found during gestation.

PurposeIntensive progress in prenatal medicine results in performing airway management in the fetus affected by life-threatening congenital malformations. This study aimed to examine age-specific reference intervals and growth dynamics for length, proximal and distal external transverse diameters, and projection surface areas of the two main bronchi at varying gestational ages, including their relative growth in length and projection surface area.Materials and methodsUsing anatomical dissection, digital image analysis and statistics, length, proximal and distal external transverse diameters, and projection surface areas of the right and left main bronchi were examined in 73 human fetuses (39 males, 34 females) aged 14–25 weeks, derived from spontaneous abortions and stillbirths.ResultsStatistical analysis showed no sex differences. Between the 14 and 25th week of gestation, the lengths of the right and left main bronchi increased from 1.43 ± 0.18 to 3.18 ± 0.39 mm, and from 2.97 ± 0.16 to 7.58 ± 1.95 mm, in accordance with the functions: , respectively. The proximal external transverse diameters of the right and left main bronchi varied from 2.13 ± 0.41 to 4.24 ± 0.20 mm, and from 1.84 ± 0.06 to 3.67 ± 0.66 mm, following the logarithmic models: , respectively. The distal external transverse diameter rose from 2.09 ± 0.47 to 4.24 ± 0.20 mm, as for the right main bronchus, and from 1.85 ± 0.04 to 3.67 ± 0.66 mm, like for the left one. On either side, there were no statistically significant differences between values of the proximal and distal transverse diameters of the main bronchus. The projection surface areas of the right and left main bronchi ranged from 2.95 ± 0.19 to 13.34 ± 2.12 mm2, and from 5.57 ± 0.21 to 28.52 ± 5.24 mm2, as and . The two main bronchi revealed a proportionate increase in both length and projection surface area, since the right-to-left bronchial length ratio and the right-to-left bronchial projection surface area ratio were stable, 0.41 ± 0.07 and 0.47 ± 0.08, respectively, throughout the analyzed period.ConclusionsThe main bronchi show no sex differences. The right and left main bronchi grow logarithmically in length and external transverse diameter, and linearly in projection surface area. The right and left main bronchi evolve proportionately, with the right-to-left bronchial ratios of 0.41 ± 0.07 for length, and 0.47 ± 0.08 for projection surface area.

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PurposesKnowledge of dimensions of fetal long bones is useful in both the assessment of fetal growth and early detection of inherited defects. Measurements of the fetal clavicle may facilitate detection of numerous defects, e.g., cleidocranial dysplasia, Holt–Oram syndrome, Goltz syndrome, and Melnick–Needles syndrome.MethodsUsing the methods of CT, digital image analysis, and statistics, the size of the growing clavicle in 42 spontaneously aborted human fetuses (21 males and 21 females) at ages of 18–30 weeks was studied.ResultsWithout any male–female and right–left significant differences, the best fit growth models for the growing clavicle with relation to age in weeks were as follows: y = −54.439 + 24.673 × ln(age) ± 0.237 (R 2 = 0.86) for length, y = −12.042 + 4.906 × ln(age) ± 0.362 (R 2 = 0.82) for width of acromial end, y = −4.210 + 2.028 × ln(age) ± 0.177 (R 2 = 0.77) for width of central part, y = −4.687 + 2.364 × ln(age) ± 0.242 (R 2 = 0.70) for width of sternal end, y = −51.078 + 4.174 × ln(age) ± 6.943 (R 2 = 0.82) for cross-sectional area, and y = −766.948 + 281.774 × ln(age) ± 19.610 (R 2 = 0.84) for volume.ConclusionsWith no sex and laterality differences, the clavicle grows logarithmically with respect to its length, width, and volume, and linearly with respect to its projection surface area. The obtained morphometric data of the growing clavicle are considered normative for their respective weeks of gestation and may be of relevance in the diagnosis of congenital defects.

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