J Korean Soc Med Ultrasound.  1997 Dec;16(4):401-405.

Normal Sonographic Appearance of Synovial Fluid in the Ankle

• Jung HJ
• Lee HK
• Youk DJ
• Rho TS
• Lee MJ
• Lee SC

Abstract

PURPOSE: To evaluated synovial fluid in ankle joint in asymptomatic volunteers with ultrasonography, We described its existence and amount.
MATERIALS and METHODS
Eighty ankles in forty asymptomatic volunteers were imaged by using a 5-10 MHz linear array US transducer in both supine and prone positions. Fluid was measured in the ankle joint recesses, in the retrocalcaneal bursa and around the tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus, peroneus brevis, and tibialis anterior tendons.
RESULTS
Fluid was detected in the anterior recess of the ankle joint in 65% (52 ankles in 80 ankles). The mean AP diameter is 0.27cm and mean longitudinal diameter is 0.46cm. Retrocalcaneal bursa fluid was found in 80% (64 in 80 ankles). The mean AP diameter is 0.12 cm and mean longitudinal diameter is 0.53 cm. There is no fluid in posterior recess and around the tendon sheath.
CONCLUSION
US of the ankle commonly depicts articular and bursal fluid in asymptomatic volunteers. The presence of fluid in these location does not necessarily imply underlying abnormality.

MeSH Terms

Ankle Joint
Ankle*
Joints
Prone Position
Synovial Fluid*
Tendons
Transducers
Ultrasonography*
Volunteers