LIGAMENTS AND MUSCLES OF THE HORSE. 15 



2. Arciform. — These pass from the lateral surfaces of the ulna 

 to blend with the lateral ligaments. 

 Synovial Membrane. 



There is a single synovial membrane. It is supported in front 

 by the anterior ligament, and laterally by the lateral liga- 

 ments, but posteriorly it is in relation to the anconeus 

 muscle. It sends a process upwards into the olecranon 

 fossa, and two downwards to lubricate the small facets be- 

 tween the radius and ulna. 



Movements. 



Flexion and extension. 



(Movement between the radius and ulna is inappreciable.) 

 In flexion, the forearm deviates a little outwards. Exten- 

 sion is limited by the beak of the olecranon and by the 

 tension of the lateral ligaments. 



KNEE JOINT. 



1. Anterior Co/?i»>ton.— Membranous.— Attached above to the 



radius, below, to the metacarpal, blending laterally with 

 the lateral ligaments. 



2. Posterior Common.— yinch thicker than preceding. At- 



tached in a similar way, its anterior surface being intim- 

 ately united to the carpal bones. 



3. Internal Za^em^.— Attached above to the internal eminence 



of the radius, below, to the large and small metacarpals, 

 giving slips to the bones over which it passes 



4. External Lat^.ral. — Attached above to the external eminence, 



of the radius, below, to the external small metacarpal, giv 

 ing slips to the cuneiform and unciform. 

 {Check Liyunent.— This is a strong fibrous band, and is a con- 

 tinuation of the posterior common ligament of the carpus. 

 It joins the tendon of the flexor pedis perforans near the 

 middle of the metacarpus.) 



