PELVIC LIMBS 693 



point at which the anterior border of the condyle leaves the straight 

 line is the top of the trochlea. 



The upper anterior part of the condyle is smooth and concave from 

 before backward, and separated from the trochlea in front by a distinct 

 crest. The lower posterior part is rough and elevated, and its highest 

 point is called the epicondyle or outer tuberosity ; the border is 

 rounded and passes into the articular surface below. Near the border 

 are two pits, whereof the anterior marks the origin of the extensor 

 longus digitorum, and the posterior the origin of the popliteus muscle. 

 Almost at the centre of the tuberosity is a circular, flattened space 

 for the insertion of the external lateral ligament of the knee-joint. 

 Above this space, just at the beginning of the supracondyloid ridge, 

 is a well-marked oval depression where the outer head of the gastroc- 

 nemius muscle arises. 



The part of the condyle seen on the posterior aspect (Fig. 532) 

 and included between the roughened lower part of the outer surface 

 and the notch which separates it from the other condyle is occupied 

 by the articular surface. This surface begins at the distal end of the 

 external half of the trochlea, curves slightly outward and downward, 

 then backward and upward, and then forward. A ridge more or less 

 plainly marked and running from without obliquely backward and 

 inward separates the trochlea from the articular surface. Its arcuate 

 outer border is the lower and posterior border already described ; its 

 inner emarginate border forms the outer margin of the intercondyloid 

 notch and is nearly parallel with the outer border ; both of these 

 borders are directed outward and backward. 



The articular surface is, of course, strongly convex from above 

 downward and convex from side to side ; the greater part of the con- 

 vexity faces inward and backward. It slopes from the outer edge 

 toward the intercondyloid notch. At the superior part of the surface 

 is a flat, smooth space whereon the sesamoid bone in the tendon of the 

 outer head of the gastrocnemius muscle glides. 



The inner condyle is not so wide transversely as the outer, and its 

 tuberosity is not so distinctly marked. On its inner or tibial surface 

 (Fig. 531) the depression above the posterior termination of the artic- 

 ular surface, for the attachment of the tendon of the inner head of the 

 gastrocnemius muscle, is shallower and smaller than the corresponding 

 depression on the external condyle. The inner supracondyloid ridge 



