synovial bursa synovial bursa a synovial bursa (plural bursae or bursas) is a small fluid-filled sac lined by synovial membrane with an inner capillary layer of viscous synovial fluid (similar in consistency to that of a raw egg white). it provides a cushion between bones and tendons and/or muscles around a joint. this helps to reduce friction between the bones and allows free movement. bursae are found around most major joints of the body. synovial bursatypical jointwithin the knee joint: bursae visible top right, middle right and bottom rightdetailsidentifierslatinbursa synovialismeshd002061ta98a03.0.00.039 a04.8.01.004ta22028thh3.03.00.0.00039 fma9692anatomical terminology structure there are four types of bursa: adventitious, subcutaneous, synovial, and sub-muscular. among these, only adventitious is non-native. when any surface of the body is subjected to repeated stress, an adventitious bursa develops under it. examples are students' elbow and bunion. clinical significance infection or irritation of a bursa leads to bursitis (inflammation of a bursa). the general term for disease of bursae is "bursopathy." history etymology bursa is medieval latin for "purse", so named for the resemblance of an anatomical bursa to a purse. bursae or bursas is its plural form.