Acupuncture to Gaohuang carries a risk of causing pneumothorax because it reaches the lungs at deep portion. This study was designed to consider a safe depth for acupuncture to Gaohuang.
1) We inserted a needle to Gaohuang on both sides of a cadaver to examine the location of the needle tip and measure the distance from the body surface of the left Gaohuang to the pleura. The tip was located at the fifth intercostal region on both sides, and the distance was 44 mm with a rib thickness of 10 mm. 2) Using 104 students, we inserted a needle to the left Gaohuang until the tip reached the rib, and measured the distance between the bodysurface and rib. The minimal distance was 14 mm. 3) We inserted a needle to Gaohuang on both sides of two males and took CT-radiographs to examine the location of the needle tip and measure the distance from the body surface of Gaohuang to the pleura. In a man of standard body size, the needle reached the rib on the left and the intercostal region on the right. The thickness of the left rib was 10.9 mm, and the distance from body surface to pleura was 33.6 mm on the left and 28.4 mm on the right. In a man of thin body size, the needle reached the rib on both sides, with the rib thickness was 9.8 mm on the left and 8.8 mm on the right. The distance from body surface to pleura was 29.4 mm on the left and 31.8 mm on the right. The above results showed that needle insertion within 19 mm (the minimal value of the measured distance between the body surface and rib + the half thickness of the rib) is safe.

The projection region of the dome of the pleura to the surface of the anterior neck was investigated in 31 domes of 17 cadavers. The point “Tentotsu”, and a line connecting that point and the most lateral edge of the acromion were adopted for a basis of measurement of the projection region. The mean length of the Tentotsu-Acromion line was 185mm on either side of the body. Its upward angle to the horizontal plane was 22° and 23° in average on the right and left sides, respectively, while its backward angle to the frontal plane was 23° on the right and 25° on the left. The right pleural domes (17 cases) were included within a range 0-58mm lateral to the Tentotsu and lower than 44mm above, and on the left side (14 cases), these values were 5-58mm and 49mm, respectively. On the other hand, when adopting the Tentotsu-Acromion line as the basis, the pleural domes were located within the medial one-third of the line. Their summits lay on the point of its medial one-fourth in medio-lateral direction, and were situated at levels lower than about 35 (on the right) or 32mm (on the left) above the line.

Twenty-six domes of the pleura of thirteen cadavers were investigated. The summits of all domes protruded above the clavicle. Mediolateral positions of the summits were located between the lateral edge of the origin of the sternal head of the sternocleidomastoid muscle (CL3) and the lateral edge of the origin of its clavicular head (CL5), and their craniocaudal positions were located between the Point “Suitotsu” (S₁₀) and the medial edge of the origin of the clavicular head (CL4). The lateral edges of the domes did not reach the level of the clavicle. Their mediolateral positions were located between CL4 and the Point “Ketsubon” (S₁₂), and their craniocaudal positions were located between CL5 and the sternal extremity of the clavicle (CL2). The medial edges of the domes were both mediolaterally and craniocaudally located between CL2 and the suprasternal point. Projection regions of the domes of the pleura to the surface of the anterior neck were included, in all cases, within the quadrate region connecting the following four points: the Point “Suitotsu” (S₁₀), a point of intersection between the median line and a line drawn vertically from the Point “Suitotsu” (S₁₀) toward the median line, the suprasternal point, and a point on the clavicle corresponding to the medial one-third of the half shoulder width.