SEBACEOUS, CERUMINOUS AND MEIBOMIAN GLANDS 



28 S 



and their appearance is quite distinctive. The larger glands are sur- 

 rounded with capillary bloodvessels. 



The ceruminous glands produce a secretion resembling the sebaceous 

 matter in many regards ; but in their anatomy they are almost identical 

 with the sudoriparous glands. They belong to the variety of glands called 

 tubular, and they consist of a nearly straight tube which penetrates the 

 skin, and a rounded or ovoid coil situated in the subcutaneous structure. 

 These glands are found only in the 

 cartilaginous portion of the external 

 auditory meatus, where they exist in 

 great number. 



The ducts of the ceruminous 

 glands are short and nearly straight, 

 simply penetrating the different layers 

 of the skin, and are y-J-Q- to g^ of an 

 inch (36 to 50 p} in diameter. Their 

 openings are rounded and about %^-Q 

 of an inch (93 p) in diameter. They 

 sometimes terminate in the upper part 

 of one of the hair-follicles. They 

 present an external coat of fibrous 

 tissue and are lined with several 

 layers of small, pale, nucleated epi- 

 thelial cells. 



The glandular coil is an ovoid or 

 rounded, brownish mass, - to 



Or -^g- Of an inch (O.2I tO O.5I Or 1.6 Fig. 62. Meibomian glands of the upper lid, 



millimeter) in diameter. It is simply x 7 



a convoluted tube continuous with the ^ 



excretory duct and terminating in a with the openings of the Meibomian glands; 4, a 



i 1-1 j. j , j . gland passing obliquely at the summit; 5, an- 



Somewhat dilated rounded extremity, other gland bent upon itself; 6, 6, two glands in 



It Occasionally presents Small lateral the form of racemose glands at their origin ; 7 , a 



_, very small gland ; 8, a medium-sized gland. 



protrusions. The diameter of the 



tube is 3^0 to 2 rib" f an mcri (^3 to IO A 6 )- ^ rias a fibrous coat, with 

 a longitudinal layer of non-striated muscular fibres, and externally a few 

 elastic fibres. It is lined by a single layer of irregularly-polygonal cells, 

 which are 2oVo to T2T7 ^ an mc ^ ( I2 to 2O /*) * n diameter. These cells 

 contain a number of brownish or yellowish pigmentary granules. The 

 glandular portion of the tube contains a clear liquid mixed with a granu- 

 lar substance containing cells. In addition to the ceruminous glands, 

 sebaceous follicles are found connected with the hair-follicles. 



The Meibomian glands have essentially the same structure as the 



