178 THE ARTICILATIONS 



examples of this form of joint are the ellww and ankk'. The knee is a miuh 

 less perfect instance. 



4. Trochoides, or wheel-like joints, where one bone rotates upon another. This 

 name is given to an articulation in which either a pivot revolves in a ring, as in the 

 sui)erior radio-ulnar; or the ring revolves about a pivot, as in the atlanto-odontoid, 

 and in a nuich less i)erfect form in the inferior radio-ulnar joint. Rotation is the 

 only movement. 



o. Arthrodia, a more or less simple gliding joint formed l)y the apposition of 

 two plane, or nearly ])lane, or concavo-convex surfaces. The amount of movement 

 is very varial)le in the different joints. Whilst in some, as the intermetacarpal, it 

 is so slight that the joints have, by some writers, !)een descril)ed as amphiarthrosis, 

 others are capal:)le of all the movements of a Imll-and-socket joint except rotation. 



The articular processes of the vertebrae and the carpal and tarsal joints are good 

 examples of the ordinary arthrodia, but under this head are also included the 

 ' ' saddle-shaped ' ' articulations, such as the sterno-costo-clavicUlar and the carpo- 

 metacarpal of the thuml:), which permit the four angular movements and circum- 

 duction, l)ut not rotation. 



Table of the Various Classes of Joints 



Class. Examples. 



I. Synarthrosis 



(a) True sutures Lambcloid, sagittal, coronal. 



(J)) False suturt'S Internasal. Intermaxillary. Costo-chon- 



dral. 

 (c) Grooved sutui'es Vomer and rostrum of sphenoid. 



II. Amphiarthrosis Bodies of vertebrae. Symphysis pubis, 



sacro-iliac, sacro-coccygeal. 

 III. Diarthrosis 



(.a) Enarthrosis Shoulder. Hip. Astragalo-scaphoid. 



(ft) Condylartln-osis Temijoro-mandibular. Occipito-atlantal. 



Radio-carpal. Metacarpo-phalangeal. 

 Metatarso-phalangeal. 

 (c) Ginglynuis or Trochlearthrosis . Elbow. Ankle. Knee. Interphalangeal 



of fingers and toes. 

 {(1) Troehoides or Lateral Gingly- 



mus Atlanto-odontoid. Superior Radio-ulnar. 



Inferior Radio-ulnar. 

 (e) Arthrodia: 



(1) Simple Lateral atlanto-axoidean. The joints be- 



tween the articular processes of the 

 vertebra3, costo-transverse and inter- 

 chondral. Acromio-clavicular. Carpal. 

 Carpo-metacarpal of four fingers. Inter- 

 metacarpal. Tarsal. Tarso-metatarsal. 

 Intermetatarsal. Calcaneo-astragaloid. 

 Superior and inferior tibio- fibular. 



(2) Saddle-shaped Sterno-costo-clavicular. Carpo-metacar- 



I)al of thumb. Calcaneo-cuboid. 



