THE PATELLA. 



399 



diameter is usually rather larger than the vertical, especially in strong, and conse- 

 quently in male, bones. 



The base^ is above with a slightly curved outline, and the apex"^ below, usually 

 somewhat internal to the middle. The outer lower border is more oblique than the 



Fig. 414. 



Tendon of quadriceps extensor 



Internal 

 articular 



facets 



External 

 ariiculai 

 facets 



Ligamentum patellae 



Ligamentum patellae 



Right patella, anterior and posterior surfaces. 



inner. The posterior surface is divided into an upper articular part and a much 

 smaller non-articular one below, in which the bone is thinner at the expense of the 



Fig. 415 



Prepatellar bursa 



Alar ligament 



Cavity of joint 



Lateral part of capsule 



Cavity of joint 



Posterior crucial ligament 

 Horizontal frozen section through right knee-joint. . 



posterior surface and is covered by the fibres of the ligamentum patellae. The 

 upper part, covered with articular cartilage and forming a part of the knee-joint, is 



^ Basis patellae. ' Apex patellae. ^Facies articularis. 



