RESUMO
SUMMARY: Some practitioners prefer the ninth costal cartilage for autogenous rhinoplasty, but few anatomical studies focus on tapering shape and harvesting safety regarding pneumothorax risk. Therefore, the authors studied the size and related anatomy of the ninth and tenth costal cartilages. Twelve fresh cadavers (24 ribs) were studied. The authors measured the length, width, and thickness of the ninth and tenth costal cartilages at the osteochondral junction (OCJ), midpoint, and tip. To evaluate safety during harvesting, the authors measured the thickness of the transversus abdominis muscle beneath the costal cartilage. The mean lengths of the ninth and tenth cartilages were 99.1 ± 25.0 and 60.6 ± 22.5 mm, respectively. The ninth cartilage was 11.8 ± 2.6, 9.0 ± 2.4, and 2.5 ± 0.5 mm wide, and the tenth cartilage was 9.9 ± 2.0, 7.1 ± 2.0, and 2.7 ± 0.5 mm wide at the OCJ, midpoint, and tip, respectively. The ninth cartilage was 8.4 ± 2.0, 6.4 ± 1.5, and 2.4 ± 0.6 mm thick, and the tenth cartilage was 7.0 ± 2.2, 5.1 ± 1.7, and 2.3 ± 0.5 mm thick at each point. For the transversus abdominis muscle, the thickness was 2.1 ± 0.9, 3.7 ± 1.0, and 4.5 ± 1.3 mm at the ninth cartilage and 1.9 ± 0.5, 2.9 ± 1.1, and 3.7 ± 1.4 mm at the tenth cartilage at each point. The size of the cartilage was sufficient for autogenous rhinoplasty. The transversus abdominis muscle provides thickness for safe harvesting. Furthermore, if this muscle is breached during cartilage harvest, the abdominal cavity is exposed, but the pleural cavity is not. Consequently, there is a very low risk of pneumothorax at this level.
