THE REGION OF THE KNEE 449 



When enlarged, this bursa projects beyond the margins of 

 the ligamentum patellae,, and so is brought into close relationship 

 with the capsule of the joint. In acute suppurative conditions,, 

 therefore, it is important that the bursa should be incised and 

 drained at an early stage to prevent the joint from becoming 

 infected. An incision is made on each side of the middle line 

 so that the bursa may be thoroughly drained. 



(3) A small subcutaneous bursa is sometimes present in front 

 of the tibial tuberosity and the distal part of the ligamentum 

 patellae. 



(4) The infra-patellar bursa is placed between the proximal 

 extremity of the tibia and the deep surface of the ligamentum 

 patellae. It is only separated from the synovial lining of the 

 joint by the infra-patellar pad of fat. When effusion takes 

 place into this bursa, there is slight fulness on each side of the 

 ligament near the tibial tuberosity, and full flexion causes pain 

 in this region. 



Postero- Lateral. (i) A bursa is situated between the 

 lateral head of the gastrocnemius and the capsule covering the 

 lateral femoral condyle ; it sometimes communicates with the 

 cavity of the knee-joint. 



(2) A small bursa is usually interposed between the biceps 

 tendon and the fibular collateral (external lateral) ligament of 

 the knee. 



(3) A protrusion of the synovial lining of the knee-joint 

 separates the tendon of the popliteus from the lateral condyle. It 

 varies in extent, sometimes forming a complete sheath for the 

 tendon and communicating distally with the cavity of the 

 proximal tibio-fibular joint (p. 460). 



(4) A small bursa separates the popliteus tendon from the 

 fibular collateral ligament. It may be incorporated with the 

 preceding bursa, when the latter is of large size. 



Postero-Medial. (i) A bursa is placed between the medial 

 head of the gastrocnemius and the capsule covering the medial 

 femoral condyle. It is frequently in communication with the 

 knee-joint. 



(2) A bursa, which frequently communicates with the 

 preceding, is situated between the medial head of the gastrocnemius 

 and the semimembranosus tendon. 



Gradual enlargement of these bursse, accompanied by pain 

 and limitation of movement at the knee-joint, is sometimes met 

 with in gamekeepers and shepherds. This is said to be due 



29 



