Abstract:

The ankle joint radiograph of children and adults were taken from antero-posterior and lateral aspect before and after water ingection, respectively.Then we can find the imaging change in the joint capsule and peripheral soft tissues when joint is normal or with hydrops by comparing the radiography with general anatomy.It's obvious that: ①The antero-posterior and lateral radiograph to normal ankle joint reveals the width of articular cavity which have no difference in children and adults.②When there are 10 mL hydrops in ankle joint of adults,we can find the watery dense shadow of joint capsule extend forward on the trochlear of talus at the anterior region of the lateral radiograph.As the injection dose increasing the shadow will be more apparent.③When there are 10 mL hydrops in children's ankle joint,the enlarged joint capsule will protrude posteriorly because of the nondeveloped fat pad.So we can find the watery dense shadow on the posterior region of the lateral rediograph.④Both of the width of the articular cavity will broader as the dose close increasing.When the hydrops come to be 25 mL,we can find the shadow of the joint capsule on the inferior of the medial malleolus on medial region,as well as the inferior of the lateral malleolus on lateral region of the antero-posterior radiograph.

Key words: artificial hydrops in ankle joint, X-ray signs, articular capsule, applied anatomy