132 CLINICAL APPLIED ANATOMY. 



rectus tendon. The patella also is raised on the surface of the 

 fluid and can be made, by a sharp tap on its anterior surface, to 

 pass backwards through the fluid and to strike the anterior sur- 

 face of the condyles of the femur. In order to obtain this latter 

 sign satisfactorily, it is well to have the quadriceps thoroughly 

 relaxed and to press the fluid from the upper part of the synovial 

 cavity into that portion which lies immediately behind the 

 patella. 



Suppurative synovitis is always an extremely serious matter, 

 particularly when depending upon staphylococcic infection, 

 because of the large absorbing surface bathed with purulent fluid. 

 The various recesses of the synovial cavity of this joint make it 

 an extremely difficult one from which to get efficient drainage ; 

 there are two condylar pouches which terminate above and 

 behind the condyles, beneath the heads of the gastrocnemius ; a 

 synovial prolongation of the outer pouch which lies along the 

 tendon of the popliteus; and the great subcrureus bursa. (Fig. 7.) 

 It is well to remember, in making lateral incisions for drainage, 

 that the one placed on the outer side will probably be the more 

 efficient, because the patient naturally tends to externally rotate 

 the limb hence the external surface becomes the most dependent 

 part and because fewer muscular fibres have to be cut through, 

 from the fact that the fibres of the external vastus do not descend 

 so low as those of the internal vastus. Opening the condylar 

 pouches of the joint on the posterior aspect needs great care on 

 account of the structures lying in the popliteal space. 



Ankle-joint. Inflammation of the ankle-joint is extremely com- 

 mon, generally as the outcome of traumatism, such as a sprain. 

 Again, all the natural depressions about the joint will become 

 obliterated, and a puffiness or swelling will appear on either side 

 of the tendo Achillis ari'el about the anterior surface of tfre joiiit 

 deep to the extensor tendons. 



Tuberculosis of Joints. Infection' of a ''synovial niembrahe 1 ' 

 with the tubercle bacillus is very frequent, and probably so 

 because it is well supplied with blood, its capillaries are some- 

 what smaller than in other tissues, and from movement and 



