ARTICULATIONS 37 



B. AMPHIARTHROSES, slightly movable articulations 



(a) Symphysis, connected by broad flattened discs of com- 

 plex fibrocartilage, e.g., bodies of vertebrae, pubic bones, rami 

 of mandible. 



(b) Syndesmosis, connected by interosseous ligaments, 

 e.g., inferior tibiofibular articulation. 



C. DIARTHROSES, freely movable articulations 



(a) Ball-and-Socket Joint, a globular head fits into a 

 cup-like cavity, free movement, e.g., hip and shoulder joints. 



(b) Condyloid Joint, a condyle fits into an eliptical cavity, 

 free movement except rotation, e.g., articulation of head and 

 neck, mandible, wrist. 



(c) Gliding Joint, two plane surfaces, or one slightly con- 

 vex and the other slightly concave, movement considerably 

 restricted by bony extension or by ligaments, e.g., articular 

 processes of vertebrae. 



(d) Saddle Joint, reciprocal concavoconvex surfaces, free 

 movement, except axial rotation, e.g., carpometacarpal joint of 

 the thumb in man. 



(e) Pivot Joint, a pivot within a ring of bone and ligament, 

 e.g., atlanto-axial articulation in neck, and radius-ulnar 

 articulation in man. 



(J) Hinge Joint, essentially concavoconvex surfaces having 

 in addition a median projection which fits into a shallow groove, 

 or other osseous projections, which allow only flexion and 

 extension. The interphalangeal joints are the true type, the 

 humeroulnar-, knee-, and ankle joints are typical in the rabbit, 

 but not in man, because in man they permit a certain amount 

 of rotation or of side-to-side movement. 



