Fig. 18
From: A practical guide for performing arthrography under fluoroscopic or ultrasound guidance
a, b This example of knee arthrography illustrates minimal pooling of contrast medium around the needle tip (arrow) reflecting mixed injection (intra-articular and extra-articular). c Mixed injection may occur when a shallow recess is approached perpendicularly with a long-bevelled needle. Better to use a short-bevelled needle (d) or to direct the needle tangentially to the cartilage (e)