536 



APPLIED ANATOMY. 



of 10 cases communicates with the joint, and effusions readily distend it. The patella 

 normally lies in contact with the femur but when there is effusion in the joint it is 

 pushed or raised up and is called a floating patella. Pressure on it causes it to strike 

 on the femur beneath, which is readily felt and enables one to diagnose effusions 

 within the joint. Posteriorly the capsule is thick, being strengthened by an expan- 

 sion, called the posterior ligament or ligamentum Winslowii, which goes upward 

 and outward from the tendon of the semimembranosus muscle at the upper edge 



of the tibia. It is pierced by the branches 

 of the azygos articular artery. The cap- 

 sular ligament is weak below at the margin 

 of the tibia and here pus may find an exit. 

 It is less liable to come out above, but 

 the bursa under the inner head of the gas- 

 trocnemius frequently (17 per cent., Mac- 



Tendon of 



adductor 

 magnus 



Tibial tubercle 



Cut edge of 

 capsule 



Biceps 



Long external 

 lateral ligament 

 Outer head of 

 gastrocnemius 

 Short external 

 lateral ligament 



External semi- 

 lunar cartilage 



FIG. 546. View of the inner side of the knee- 

 joint; the capsule has been cut away from the edge 

 of the patella to the internal lateral ligament, ex- 

 posing the interior of the joint. 



FIG. 547. View of the outer side of the knee-joint. 

 The capsule has been cut away from the edge of the 

 patella to the external lateral ligament. 



alister) communicates with the joint and is usually the origin of the ganglion so often 

 seen in the popliteal region. When the joint becomes subluxated by disease the tibia 

 is drawn backward and this posterior capsular ligament may shorten and prevent 

 reposition forward. So strong is it that forcible attempts are liable to cause fracture. 

 Internally the capsular ligament is strengthened by the lateral expansion from 

 the side of the patella and from the fascia lata over the vastus internus; these 

 go to the inner tuberosity of the tibia and strengthen the lower part of the joint, 



