Table 2.

Total number of ring types identified and the distribution based on their location on the trachea

Ring type	Absolute # of rings (% of the total # of rings)	% of specific ring type found
		Upper 1/3 of trachea	Middle 1/3 of trachea	Lower 1/3 of trachea
A	86 (58)	34	49	17
B	13 (9)	31	31	38
C	8 (5)	38	12	50
D	4 (3)	25	50	25
E	2 (1)	50	50	0
F	1 (1)	0	100	0
G	6 (4)	83	17	0
H	3 (2)	100	0	0
I	6 (4)	0	0	100
J	3 (2)	67	33	0
K	1 (1)	0	0	100
L	14 (10)	50	36	14
Total	147 (100)