FIBRO-CARTILAGINOUS TISSUE. 159 



and thyroid gland. Cartilage is also frequently completely 

 transformed into bone, as the costal, connecting the ribs 

 with the sternum. The relations of the cartilaginous system 

 are very important and extensive. In the young state it 

 represents the entire osseous system, and without it the 

 skeleton could have no proper existence or motion. It also 

 enters into the organs- of voice and respiration. Hence 

 the utility of this tissue, the close relationship and de- 

 pendence of other tissues upon it, and, consequently, the 

 well-being of the whole ceconomy on its integrity and 

 preservation. 



CHAPTER X. 



FIBRO-CARTILAGINOUS TISSUE. 



THIS tissue, as its name implies, consists of both fibre 

 and cartilage, uniting the tenacity of the former with the 

 density and elasticity of the latter. It presents three 

 varieties. 



1. The membraniform as seen in the external ear, alee of 

 the nose, cartilages of the eyelids and the trachea. 



2. The inter-articular, found between the bodies of the 

 different vertebrae, at the clavicle, inferior maxillary, and 

 knee-joints. 



3. The trochlea for the gliding of tendons. 



The cotyloid and glenoid ligaments, which deepen the 

 articular cavities of the thigh and shoulder joints, belong 

 also to this class. 



The fibres of this tissue are said to run in every direction, 

 some parallel, others interlaced and crossed, others concen- 

 tric, and all having their spaces filled with cartilage. Desic- 

 cation makes it yellow and transparent like the ligaments. 

 Boiling reduces it to gelatin. The first variety only has 

 perichondrium, the others adhering to the bone or being 

 covered by synovial membrane. 



The functions of this system vary in different parts. We 



