The arrows on the adult's foot photographed here point to the anterior tibial tendon. In most patients, this may not be as easy to see as in this photo, however, locating this tendon by palpation is usually not difficult when asking the patient to DORSI flex against force. The anterior margin of the medial malleolus is also easy to locate. These landmarks are shown on our 2-year old patient's ankle as two vertical marks (right image). The lateral mark (lighter) is drawn over the anterior tibial tendon and the medial mark (darker) is drawn over the anterior margin of his medial malleolus. Have the patient supine with the foot in slight PLANTAR flexion. Plantar flexion opens the ankle joint space wider.

 

 

Notice how the joint space is relatively closed in dorsiflexion and more open in plantar flexion. Plantar flexion optimizes needle entry into the joint space.The puncture site is between the two landmarks. Prep the area with povidone-iodine solution, and anesthetize the skin with 1% lidocaine. To aspirate, have an 18 or 20 gauge needle with a 10 ml syringe. Insert the needle medial to the anterior tibial tendon and aim toward the anterior edge of the medial malleolus. Aspirate the fluid in the joint space.