ABSTRACT
Objective To explore the morphology and the tissue structure of acromioclavicular joint. Methods Anatomical analysis was performed on 27 fresh adult cadavers and the morphology of the acromioclavicular joint was observed. The relevant bone structure and ligament parameters were measured, and the specimens were randomly divided into group A and group B. Group A reserved the acromioclavicular ligament and coracoclavicular ligament, and group B reserved only the acromioclavicular ligament. The difference in tension between the two groups was compared. Results The distance from the midpoint of the conical ligament to the distal end of the clavicle was (42.68 ± 6.34) mm, the width of the end point was (16.97 ± 4.28) mm, and the thickness of the center point was (5.39 ± 0.34) mm; the distance from the midpoint of the trapezoidal ligament to the clavicle was (20.35 mm ± 4.18) mm, the width of the end point was (10.35± 1.31) mm, the thickness of the center point was (5.19 ± 0.342) mm; the average vertical distance from the base of the coracoid process to the surface of the clavicle was 30.75 mm, and the mean coracoclavicular gap was 12.02 mm; the length of the central axis of the conical ligament was (15.68 ± 3.30) mm and the angle was (117.25 ± 10.80) °, while the length of the central axis of the trapezoidal ligament was (9.67 ± 2.25) mm, and the angle was (75.42± 11.37) °. The distance between the start joint of the trapezoidal ligament and the trapezium was (8.96± 3.00) mm, and the distance between the end points (13.09± 3.50) mm. The average tensile force of group A was higher than that of group B [(610.04 ± 51.24) N vs (560.41 ± 44.63) N, P < 0.05]. Conclusion During distal clavicular resection, the resection of the distal clavicle shall be within 10-30 mm. The depth shall not exceed 42 mm when drilling under the coracoid process. The reconstruction of the coracoclavicular ligament during acromioclavicular joint dislocation has an anatomical and biomechanical basis.
ABSTRACT
Trisomy 11 mosaicism is clinically rare, for which making diagnostic and treatment decisions can be challenging. In this study, we used noninvasive prenatal testing, chromosome karyotype analysis, chromosome microarray analysis, copy number variation sequencing and fluorescence in situ hybridization for detecting trisomy 11 mosaicism in two cases and provided them with genetic counseling. In one of the cases, the fetus with confined placental mosaicism trisomy 11 presented with severe growth restriction and a placental mosaic level of 44%, and pregnancy was terminated at 25+3 weeks of gestation. In the other case with true low-level fetal mosaicism of trisomy 11, the pregnancy continued after exclusion of the possibility of uniparental disomy and structural abnormalities and careful prenatal counseling. The newborn was followed up for more than one year, and no abnormality was found. Noninvasive prenatal testing is capable of detecting chromosomal mosaicism but may cause missed diagnosis of true fetal mosaicism. For cases with positive noninvasive prenatal testing but a normal karyotype of the fetus, care should be taken in prenatal counseling and pregnancy management.