EXTREMITIES. 21 



Sesamoids. — Two in number, three faces ; anterior 

 face : articular, concave facettes ; external face : for 

 implantation; posterior face : covered by fibro-cartilage. 

 Base for ligamentous insertion and looking down. 

 Apex looks upwards. 



Development : one nucleus of ossification. 



Navicular. — Anterior face : articular, two concave 

 facettes, median eminence ; posterior face : covered 

 with iibro cartilage ; anterior border : flat facette ; 

 posterior border and two extremities for ligamentous 

 attachments. 



Development : one nucleus of ossification. 



SYNDESMOLOGY. 



ScAPULo-HUMERAL JOINT. — Eiiartlirosis. Glenoid 

 cavity of scapula and articular head of humerus. 

 Capsular ligament with two re-enforcing bands. One 

 synovial capsula. All motions. 



HuMERO - RADIAL JOINT. — Augular ginglymus or 

 perfect hinge. Condyle and double trochlea of 

 humerus, glenoid cavity and double groove of radius 

 with sigmoid notch of cubitus. One anterior capsular 

 ligament and two funicular lateral, the internal the 

 longest, the external the thickest. One synovial 

 capsula with three culs de sac. Flexion and exten- 

 sion. 



