THE STERNOCLAVICULAR ARTICULATION 129 



cartilage is a thin articular disk, smaller than the ones between 

 the vertebrae. It is placed between the adjoining articular 

 facets of the sacrum and coccyx. 



4. The Articulation of the Pubic Bones 



It is an amphiarthrodial joint formed by the junction of 

 the two pubic bones to form the symphysis. The ligaments 

 are the anterior, posterior, superior, and inferior pubic. 



Interpubic disk. The ligaments pass from the contiguous 

 surfaces of the bones. The interpubic disk consists of fibro- 

 cartilage placed between the two articulating surfaces. Each 

 surface is covered by hyaline cartilage, attached to the bony 

 surfaces. 



ARTICULATIONS OF THE UPPER EXTREMITY 



The Sternoclavicular Articulation 



The ligaments are capsular, anterior and posterior sterno- 

 clavicular, inter articular fibrocartilage; inter clavicular and costo- 

 damcular. 



The capsule for this joint is made up mostly of strengthening 

 bands; it is weakest at the lower anterior angle. It completely 

 surrounds the joint. In front a band called the anterior Sterno- 

 clavicular ligament passes from the inner extremity of the 

 clavicle obliquely down and into the upper part of the manu- 

 brium; the posterior Sternoclavicular ligament passes in a similar 

 direction, and is related behind with the sternothyroid and 

 sternohyoid muscles. 



The interarticular cartilage is attached above to the upper 

 and posterior border of the inner extremity of the clavicle, 

 and below to the junction of the first costal cartilage with the 

 sternum, and by its circumference to the capsule; thus the 

 cartilage of the first rib is partly within this joint. Its cir- 

 cumference is thicker than its centre, which may be perforated ; 

 in size and shape it varies greatly. It lessens the inequalities 

 of the two bony surfaces, and divides the joint into two parts, 

 each provided with a synovial membrane. In young bones 

 the interclavicular notch on the sternum* is ^covered by hyaline 

 cartilage. 

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