THE LIMBS OF THE HOESE 



69 



freedom. Adduction and abduction are restricted by the sub- 

 scapular and infraspinous insertions, and rotation and circumduction 

 are limited by the other muscular attachments about the joint. 



The elbow .ioint (articulatio cubiti). — The term "elbow joint," 

 strictly speaking, includes three joints, namely, the Mimero-radicd 



Lis. collaterale laterale. 



-Humerus. 



Radius . - 



M. biceps^brachii. 



M. brachialis. 



Lig. collaterale mediale 



(long). 



Fig, 48. — Anterior Aspect of the Elbow Joint. 

 The red line indicates the line of attachment of the synovial lining of the joint capsule. 



articulation (articulatio humeroradialis), the hitmero-nlnar articula- 

 tion (articulatio humeroulnaris), and the proxi^iial radio-nlnar articula- 

 tion (articulatio radioulnaris proximalis). In describing the joint of the 

 horse it is convenient to include tlie union between the shafts of the 

 radius and ulna as well. 



The opposed bony surfaces of the humerus and the radius and ulna 

 are so moulded and adapted to each other as to convince the dissector 

 that movement in the joint can take place in one plane only. The 

 presence of strong collateral ligaments contributes to the limitation 

 of movement to flexion and extension. 



The joint capsule (capsula articularis), attached to the articular 

 margins of all three bones, is strongest on the extensor (anterior) 



