62 OSTEOLOGY OF THE HORSE. 



thicker, the internal the more projecting, of the two. They ex- 

 hibit bold, convex, rounded articulatory surfaces, presenting infe- 

 riorly and posteriorly, which rest upon the tibia ; on their sides 

 are rough eminences for the attachment of the lateral ligaments ; 

 and between them is a deep asperous fossa, into which are implant- 

 ed the inter-articular or crucial ligaments. At the base of the ex- 

 ternal condyle, below and in front of it, is a pit from which springs 

 the tendon of the extensor pedis. From the condyles, posteriorly, 

 proceed epicondyloid ridges, uniting them with the body of the 

 bone. 



Connexiou. — With the pelvis, above ; with the patella and 

 tibia, below. 



Development — The extremities in the growing animal are 

 epiphyses : prior to the adult period, however, they become con- 

 solidated with the body ; and the inferior extremity earlier than 

 the superior. 



STIFLE liONE. (PATELLA.) 



Situation — Upon the trocheal surface of the inferior extremity 

 of the round bone. 



Outline — Quadrangular : convex externally ; irregularly con- 

 cave internally. 



Division — Into three surfaces and four angles. 



The anterior surface is convex, most prominent towards 

 the middle, and in places porous and roughened by tendinous 

 and ligamentous attachments. 



The posterior surface is entirely articulatory, and un- 

 equally divided by an eminence running across it into two shallow 

 concavities, which are adapted to the condyles of the round bone, 

 the inner being the larger one. 



The superior surface, the space bounded by the superior 

 and lateral angles, is uneven and roughened by the implantation 

 of the tendons of the rectus and vasti muscles. 



The angles are all blunt or rounded off. To the superior is 

 fixed the tendon of the rectus ; to the inferior and lateral, the li- 

 gamenta patellae : between the superior and external lateral one is 

 an eminence looking like a fifth angle : it gives attachment to the 

 vastus externus. 



Connexio)i—By muscles and its capsular ligament, with the 

 round bone; by its own four proper ligaments, with the tibia. 



OF THE THIGH. 



The bone correspondent to the bone of the thigh— the veritable 

 osfemoris of a man, in the horse enters into the formation of the 

 part we call the haunch; while the tibia and fibula, the human 



