202 



THE ARTICULATIONS OF THE HORSE 



(1) The tibial and fibular tarsal bones are united by four bands (astragalo-calcaneal liga- 

 ments). The internal ligamentjextcnds from the sustentaculum tali to the adjacent part of the 

 tibia tarsal, blending with the short lateral ligament. The external ligament extends from the 

 anterior process of the fibular tarsal to the adjacent part of the external ridge of the trochlea. 

 The superior ligament extends from the posterior margin of the trochlea to the fibular tarsal. 

 The interosseous ligament is deeply placed in the sinus tarsi between the two bones, and is attached 

 in the rough areas of the opposed surfaces. 



(2) The smaller bones are attached to each other as follows: The central and third tarsal are 

 united by an interosseous and an oblique anterior ligament (scaphoido-cunean ligaments). 

 The central and fourth tarsal are united by an interosseous and a transverse external ligament 

 (cuboido-scaphoid ligament). The third and fourth tarsals are similarly connected (cuboido- 

 cunean ligaments). The third tarsal is joined by an interosseous (intercunean) ligament to the 



Superficial flexor tendon 



Gastrocnemius tendon 



Tarsal tendon of 

 biceps femoris 



Calcanean bursa 



Gastrocnemius 

 bursa 



Tuber calcis 



Upper pouch of 

 joint capsule 



Tibial tarsal bone 



Interosseous ligament 



Plantar ligament 



Fourth tarsal bone 



Interosseous ligament 

 Large metatarsal bone 



Suspensory ligament 

 Check ligament 



Deep flexor 

 Tibia 



Tibialis anterior 

 P crone us tertius 



Tibio-tarsal joint cavity 

 Joint capsule 

 Central tarsal bone 

 Third tarsal bone 



Distal annular ligament 



Fig. 166. — Sagittal Section of Hock of Horse. 



(fused) first and second tarsals; the latter are connected with the fourth tarsal by a transverse 

 posterior ligament. 



(3) The smaller bones are connected with the upper row as follows: The central is attached 

 to the tibial tarsal by posterior and interosseous (astragalo-scaphoid) ligaments, and to the fibular 

 tarsal by a short ol)licjue (calcaneo-scaphoid) liand. The fourth is attached to the fibular tarsal 

 by interosseous and posterior (calcaneo-cuboid) ligaments. The (fused) first and second tarsals 

 are connected with the fibular tarsal by a posterior (calcaneo-cunean) ligament. 



(4) The lower tarsal bones are connected with the metatarsus by tarso-metatarsal ligaments, 

 which are not distinct from the common ligaments, except in the case of the interosseous ligament 

 between the third tarsal and metatarsal l)ones. 



Movements. — These are flexion and extension, which take place at the til^io- 

 tarsal joint. The movements between the tarsal bones, and between the latter 

 and the metatarsus, are so limited as to be negligible so far as the action of the joint 

 as a whole is concerned. In the standing position the articular angle (in front) 

 is about 150° to 160°. Complete extension is prevented by tension of the lateral 

 ligaments. Flexion is checked only by contact of the metatarsus with the leg, 



