The lengths and diameters of the trachea and bronchi, the angle formed at the bi-furcation of the trachea were measured in 141 Chinese adult cadavers. The length of the trachea measured in 141 specimens was 71--134 mm with110.77?9.94 mm as an average. The internal transverse diameter of the trachea was9.5--22.0 mm, having an average of 16.17?2.61 mm. The internal sagittal diametervaried from 8 to 22.5 mm, with 14.73?2.68 mm as the average. The transverse dia-meter is greater than sagittal. The angle formed at the bifurcation of the trachea variedfrom 35?--92?, averaged 68.09??11.82?. The angle is greater in female than in the malefor about 5?. The left bronchus had a length of 42--63 mm (average, 51.89?4.18 mm),doubled that of the right one (15--36 mm average, 26.18?4.05 mm).

The pattern of branching and distribution of the blood vessels in the right lowerlobe of 50 adult Chinese lungs were studied and the following results were obtained. 1. In 68% of the specimens, the A~6 arose as a single branch, which bifurcated intotwo (50%) or three rami (18%). In 30% of the cases there were two separate A~6arteries and in 2% there were three. 2. The subsuperior bronchus (B~*) might be supplied with 1--3 arteries. Twenty-seven arteries to 22 subsuperior bronchi were found in 19 cases whereas fifty nine arteriesto 57 accessory subsuperior bronchi (BX_(10)~*) occurred in 43 cases. 3. A~7 occurred in 78% as a single branch, among which 34% were branched offfrom the basal artery and the remaining arose in combination with other arteries. A~7occurred in two branches in 22%. A~8 arose as a single branch in 22% and in com-bination with other arteries in 44%. 34% of A~8 was present in two branches, thereforethe variations of A~8 are far greater than that of B~8. The arteries to the lateral basalsegment (A~9) arose as a single branch of the basal artery in 44% of the specimens. Inanother 38% A~9 was of two branches. In the remaining 16%, it was associated withbranches to the neighboring segments. In 98% of the specimens, the artery to the pos-terior basal (A~(10)) divided into A~(10) a and A~(10)b. 4. The veins from the different segments of the right lower lobe were drained intotwo principal pulmonary veins. A superior vein (V~6), which is usually a single branch,occasionally two branches (18%), drained the vein from the superior segment, and alower vein (common basal vein) draining the veins from the basal segments. The com-mon basal vein formed by the union of a superior and an inferior basal veins was foundin 90% of the specimens. The basal veins may be classified into three types; the un-complicated type is the prevailing pattern which occurs in 52%.

The pattern of branching and distribution of the segmental bronchi in the rightlower lobe of 50 adult Chinese lungs were studied and the following results were ob-tained. 1. In 98% of the cases the superior segmental bronchus (B~6) arises as a single stem,which is either divided into 2 branches (86%) or 3 branches (12%). In the formercase, the prevailing pattern (68%) has the formula B_(a+b)~6 and B_6c. In 22% of the cases, the superior segment is obliquely fitted to the basal segmentsof the lower lobe, and in the remaining 76% it caps the basal segments horizontally. Only in one instance (2%), B~6 arises as two separate stems. In 38% of the cases the subsuperior bronchus proper (B~*) is present. In some cases(6%) of this group there are two B~* in the same lobe. The accessory subsuperior bronchus (BX_(10)~*) is found in 86% of the cases. It maybe represented by 1--3 stems. The B~x or BX_(10)~* almost always distributes to at least the posterior section of thelung but it may spread medially to the paravertebral area or laterally to the postero-lateral zone. 2. The percentages of occurrence of types Ⅰ, Ⅱ, Ⅲ and Ⅳ of the medial basal bron-chus (B~7) are 38%, 30%, 16% and 16% respectively. The anterior basal bronchus (B~8) is remarkably constant in occurrence and pattern,80% of B~8 bifurcated into B_a~8 and B_b~8, 18% is expanded by the inclusion of the sub-segmental bronchus of adjoining segments, and 2% is defective. The lateral basal bronchus (B~9) divides typically into B_a~9 and B_b~9 in 82% of thecases. Only 2% of B~9 is expanded, this is due to the inclusion of the displaced B_b~8. Inthe remaining 16%, B~9 is defective. In such instances its two subsegmental bronchiarise independently, one has developed at the usual site of B~9, the other arises as a dis-placed branch usually from main trunk of B~(10). In all specimens, the posterior basal bronchi (B~(10)) divides into B_a~(10) and B_b~(10). Onlyin two specimens, B_b~(10). is expanded by inclusion of the displaced B_b~7. 3. The lengths and the relative levels of the segmental bronchi of the right lowerlobes were measured.