48 EQUINE ANATOMY. 



external is articular and has a facet on the outside for 

 articulation with the fibula — it is separated from the 

 anterior by a groove ; the internal tuberosity is also 

 articular and has posteriorly a small tubercle for liga- 

 mentous attachment. On the middle of the superior 

 extremity is the tibial spine. The inferior extremity 

 lias a double articular pulley, outwards a tuberosity 

 with a vertical groove, and inwards another tuberosity 

 wdth an oblique groove posteriorly. Development : 

 four nuclei of ossification. 



Fibula. — Division: Middle part and two extremities. 

 Middle part forms the tibial arch. Extremities : the 

 superior, or head, is wide and has inwards a facet for 

 articulation, outwards it shows muscular imprints ; the 

 inferior ends in a blunt point. Development : one 

 nucleus of ossification. 



Patella. — Division : Three faces and a circumfer- 

 ence. The anterior face is convex and irregular ; the 

 superior roughened for muscular attachments ; the 

 posterior is moulded on the" femoral trochlea. The 

 circumference unites with the three faces. Develop- 

 ment : one nucleus of ossification. 



Digital Region.— Tarsus. — Division: Six or seven 

 bones arranged in two rows. The superior row has 

 the astragalus with its six faces ; the superior, anterior, 

 inferior and posterior are articular ; the external and 



