A MORPHOLOGICAL STUDY OF THE TBACHEAL AND 

 BRONCHIAL CARTILAGES, 



BY WILLIAM SNOW MILLER. 



Horner, writing in 1839, said that "at the orifice of each branch of the bronchia 

 there is a semi-lunar cartilage, forming rather more than one-half of its circum- 

 ference and having its concave edge upwards. The whole arrangement resembles 

 somewhat the pasteboard of an eared bonnet, and is evidently to keep the orifice 

 open." Passing over his reference to the feminine fashions of his day, we find in 

 the above quotation the earliest description of the form of the cartilages found at 

 the place where bronchi divide; moreover, a reason is assigned for the particular 

 form of the cartilage. 



In 1840 Jonas King published a short article "On the forms of the cartilages 

 which keep open the principal divisions of the bronchial tubes." In a footnote 

 he frankly gives the priority of description to Professor Horner and intimates that 

 his paper was inspired by a demonstration Professor Horner made in Philadelphia 

 to Mr. T. Wilkinson King "some months previous to the last edition of his work." 

 Mr. King must have, on his return to London, imparted the information thus 

 acquired to his namesake, who at once made it the subject of a special study. King 

 found, however, that not all the cartilages present at the place where a bronchus 

 divides had the characteristic saddle shape described by Horner but, "that a con- 

 siderable number of varieties will be met with." His paper is illustrated with 

 several small and unsatisfactory drawings of the cartilages. 



An extended search of the literature fails to bring to light any other investiga- 

 tion of the form of the tracheal or bronchial cartilages; in no place has the author 

 been able to find the cartilages illustrated in plastic form, and such illustrations as 

 are found show the cartilages as irregular plates and are evidently schematic. 



Henle's illustrations are poor, but his description is fairly good. He describes 

 the cartilages as having the plates or strips sometimes with short prolongations, 

 arranged, as a rule, transverse to the long axis of the bronchi; they may also have 

 a longitudinal or oblique direction 



" Je tiefer hinab, um so mehr reduciren sie sich und um so welter riicken sie aus einander, 

 bis sie endlich nur noch als platte Ringe oder Halbringe um die Miindungen der Seitenzweige 

 und als Stiitzen der die beiden Aeste einer gabligen Theilung trennenden Scheidewand 

 vorkommen." 



The description of Waters is inexact and his illustrations still more so. He 



states that the cartilages 



" In the largest bronchial tubes are elongated transversely and placed more as 

 they are in the bronchi, but in the secondary and subsequent divisions they are placed 



very irregularly, and are elongated longitudinally In the larger tubes, wherever 



a branch arises, a cartilage is always placed, and in the largest vessels the cartilage 



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