MECHANISM AND FUNCTIONS OF THE JOINTS. 165 



obliquely across the intercostal spaces, and hold the ribs and 

 their cartilage firmly together. 



Sternal ligaments. — These several pieces of the breast 

 bone are united to each other by intervening cartilaginous 

 substance j in addition to which they are connected by liga- 

 mentary bands, both inwardly and outwardly. The fore part 

 of it is surmounted by a broad portion of cartilage, which 

 runs along its under part. 



ARTICULATIONS OF THE FORE EXTREMITY. 



Shoulder joint. — The capsular ligament around this joint 

 is strengthened in many places by additional fibres dispersed 

 upon its exterior. It is fixed to the rough margin of the glenoid 

 cavity, and to the neck of the os humeri. A synovial mem- 

 brane lines it, which may be followed upon the cartilagi- 

 nous surfaces of the bones. Externally, this ligamentous cap- 

 sule is clothed on every side by muscle ; and to them is 

 attributed the main strength of the joint. 



Elbow joint. — The ligaments of it are two lateral and a 

 capsular. 



Knee joint. — In the knee there are five distinct articula- 

 tions ; one between the radius and the three small bones of 

 the upper row ; a second between the small bones, above 

 and below ; a third between those of the lower row and the 

 metacarpal bones ; a fourth between the os trapezium and 

 the os cuneiforme ; and a fifth between the os pisiforme and 

 os trapezoides : they have all separate capsular ligaments and 

 synovial linings. 



The ligaments of the knee, and the tendons passing over it, 

 are girt by broad, glistening, ligamentous bands, which retain 

 the latter in their places, and render the joint stronger and 

 more compact. Between these ligaments, fascia, and the ex- 

 tensor tendons, are some small bursas. 



External lateral ligament runs from a tubercle upon the 

 radius to the head of the external metacarpal bone. 



Internal lateral ligament consists o f two parts, which 



