THE STIFLE JOINT 233 
half an inch wide, and lies under the narrow articular area which connects the trochlea and medial 
condyle. The lateral communication occurs in 18 to 25 per cent. of cases, according to Baum; in 
rare cases it is larger than the inner one. It is instructive to distend this capsule and thus obtain 
an idea of its potential capacity and relations (Fig. 246). 
Ligaments.—The femoro-patellar ligaments, lateral and medial (Lig. femoro- 
patellare fibulare, tibiale), are two thin bands which reinforce the capsule on either 
Patella 
Femur 
Accessory cartilage of 
patella 
Medial ridge of trochlea 
Medial patellar ligament Biceps femoris 
Lateral patellar ligament 
Medial epicondyle 
Medial femoro-tibial 
: — Lateral femoro-tibial 
ligament 
ligament 
Medial meniscus : 
Lateral meniscus 
AEE tibi 
eee coraiyle of bia Lateral condyle of tibia 
Tuberosity of tibia 
Interosseous space 
Fibula 
—___ Interosseous ligament 
Fic. 245.—Lerr Stirte Joint or Horse; Front View. THe CapsuLes ARE REMOVED. 
1, Middle patellar ligament; 2, stump of fascia lata; 3, stump of common tendon of extensor longus and peroneus 
tertius. 
side. The lateral ligament is fairly distinct; it arises from the lateral epicondyle of 
the femur just above the lateral femoro-tibial ligament, and ends on the lateral 
border of the patella. The medial ligament is thinner and is not distinct from the 
capsule; it arises above the medial epicondyle, and ends on the patellar fibro-car- 
tilage. 
The patellar ligaments (Ligg. patellx)! are three very strong bands which at- 
_ 1} They are also termed the straight ligaments of the patella. This term seems objectionable 
since they are all oblique in direction. 
