NORMAL HISTOLOGY. 



Numerous fine hairs and large sebaceous glands occur in the cartilaginous 

 portion, but diminish in size and frequency towards the bony canal, in which 

 they are entirely wanting. Within the cartilaginous meatus and along the 

 roof of the bony tube, the skin is closely beset with the large coiled 

 ceruminous glands, which resemble in structure modified sweat-glands. 

 Like the latter, the ceruminous glands consist of a deeper and wider 

 coiled portion, the secretory segment, and a long narrow excretory duct, 

 which ends in most cases independently on the free surface of the skin. 



Sebaceous gland 



Cartilage 



Ceruminous 

 gland 



Cartilage 



Hair-follicle 



Corium 



FIG. 413. Section of skin lining cartilaginous part of external auditory canal. X 30. 



Sometimes, particularly in the very young child, it may open into the 

 duct of a sebaceous gland. The cuboidal secreting cells contain yellowish 

 brown pigment particles and granules resembling fat. The ear- wax or 

 cerumen is, as usually found, the more or less dried mixture of the secre- 

 tions derived from both varieties of glands, together with discarded squamous 

 epidermal cells. 



The blood-vessels distributed to the interior of the external auditory 

 canal pierce the membranous roof of the cartilaginous meatus and the associated 

 fibrous tissue and form capillary networks within the perichondrium and peri- 

 osteum and, within the skin, around the glands and the hair follicles. The 

 deeper veins of the meatus drain the bony and a small part of the cartilaginous 

 meatus. The lymphatics of the external auditory canal arise from a 

 cutaneous network, from which trunks pass in three general groups, as do 

 those of the auricle. The nerves supplied to the external auditory canal, 



