<p begin="00:00:07.639" end="00:00:09.351" style="s2">- [Voiceover] A linear array transducer</p>
<p begin="00:00:09.351" end="00:00:11.510" style="s2">with a musculoskeletal exam type</p>
<p begin="00:00:11.510" end="00:00:14.415" style="s2">is used to perform an<br />ultrasound guided aspiration</p>
<p begin="00:00:14.415" end="00:00:16.039" style="s2">of a Baker's cyst.</p>
<p begin="00:00:16.039" end="00:00:18.528" style="s2">The patient is in a supine position.</p>
<p begin="00:00:18.528" end="00:00:20.870" style="s2">The transducer is placed transversely</p>
<p begin="00:00:20.870" end="00:00:22.752" style="s2">over the popliteal fossa,</p>
<p begin="00:00:22.752" end="00:00:26.088" style="s2">with the orientation marker<br />directed to the patient's right.</p>
<p begin="00:00:26.088" end="00:00:28.820" style="s2">The most common location<br />for a Baker's cyst</p>
<p begin="00:00:28.820" end="00:00:31.767" style="s2">is at the crossing of the<br />semimembranosus muscle</p>
<p begin="00:00:31.767" end="00:00:32.839" style="s2">and the medial head</p>
<p begin="00:00:32.839" end="00:00:36.367" style="s2">of the gastrocnemius muscle<br />above the femoral condyle.</p>
<p begin="00:00:36.367" end="00:00:38.343" style="s2">The femoral condyle is seen as a</p>
<p begin="00:00:38.343" end="00:00:41.719" style="s2">bright hyperechoic structure<br />on the left of the screen.</p>
<p begin="00:00:41.719" end="00:00:43.494" style="s2">The speckled pattern of the tendon</p>
<p begin="00:00:43.494" end="00:00:45.454" style="s2">of the semimembranosus muscle,</p>
<p begin="00:00:45.454" end="00:00:47.718" style="s2">and the starry night<br />appearance of the medial head</p>
<p begin="00:00:47.718" end="00:00:50.591" style="s2">of the gastrocnemius can<br />be seen as the transducer</p>
<p begin="00:00:50.591" end="00:00:52.535" style="s2">is moved more distally.</p>
<p begin="00:00:52.535" end="00:00:54.071" style="s2">A Baker's cyst appears as a</p>
<p begin="00:00:54.071" end="00:00:58.903" style="s2">C-shaped, darker hypoechoic<br />or anechoic cystic structure,</p>
<p begin="00:00:58.903" end="00:01:01.746" style="s2">with a superficial and deep component.</p>
<p begin="00:01:01.746" end="00:01:04.871" style="s2">The transducer is rotated<br />90-degrees clockwise,</p>
<p begin="00:01:04.871" end="00:01:06.143" style="s2">with the orientation marker</p>
<p begin="00:01:06.143" end="00:01:08.472" style="s2">directed toward the patient's head.</p>
<p begin="00:01:08.472" end="00:01:11.095" style="s2">The extent and depth of the Baker's cyst</p>
<p begin="00:01:11.095" end="00:01:12.946" style="s2">should be confirmed by scanning</p>
<p begin="00:01:12.946" end="00:01:15.839" style="s2">the cyst proximally and distally.</p>
<p begin="00:01:15.839" end="00:01:17.806" style="s2">The needle is inserted in the skin</p>
<p begin="00:01:17.806" end="00:01:20.287" style="s2">just proximal to the transducer.</p>
<p begin="00:01:20.287" end="00:01:22.913" style="s2">The needle is slowly<br />advanced to lie in plane</p>
<p begin="00:01:22.913" end="00:01:24.358" style="s2">to the transducer beam,</p>
<p begin="00:01:24.358" end="00:01:28.447" style="s2">and is seen as a bright,<br />hyperechoic linear structure.</p>
<p begin="00:01:28.447" end="00:01:30.041" style="s2">The needle is slowly advanced</p>
<p begin="00:01:30.041" end="00:01:32.262" style="s2">under direct ultrasound visualization,</p>
<p begin="00:01:32.262" end="00:01:33.623" style="s2">until the tip is seen to lie</p>
<p begin="00:01:33.623" end="00:01:35.022" style="s2">within the Baker's cyst,</p>
<p begin="00:01:35.022" end="00:01:37.647" style="s2">where an aspiration can be done.</p>
<p begin="00:01:37.647" end="00:01:39.415" style="s2">After the procedure is finished,</p>
<p begin="00:01:39.415" end="00:01:40.700" style="s2">the area should be scanned</p>
<p begin="00:01:40.700" end="00:01:42.782" style="s2">to ensure that there is<br />no evidence of bleeding</p>
<p begin="00:01:42.782" end="00:01:43.865" style="s2">in this area.</p>

<p begin="00:00:07.889" end="00:00:09.349" style="s2">- [Voiceover] A linear array transducer</p>
<p begin="00:00:09.349" end="00:00:12.631" style="s2">with a nerve exam type is used<br />to perform ultrasound guided</p>
<p begin="00:00:12.631" end="00:00:14.687" style="s2">popliteal nerve block.</p>
<p begin="00:00:14.687" end="00:00:17.850" style="s2">The target depth is<br />approximately 2 to 4 centimeters</p>
<p begin="00:00:17.850" end="00:00:20.373" style="s2">in an 80 kilogram adult.</p>
<p begin="00:00:20.373" end="00:00:23.568" style="s2">The patient is positioned in<br />a lateral decubitus position</p>
<p begin="00:00:23.568" end="00:00:26.091" style="s2">with the hip and knee slightly flexed.</p>
<p begin="00:00:26.091" end="00:00:28.135" style="s2">The transducer is placed transversely</p>
<p begin="00:00:28.135" end="00:00:31.135" style="s2">on the popliteal skin<br />crease with the orientation</p>
<p begin="00:00:31.135" end="00:00:33.388" style="s2">marker directed laterally.</p>
<p begin="00:00:33.388" end="00:00:36.393" style="s2">The transducer should be<br />moved medially and laterally</p>
<p begin="00:00:36.393" end="00:00:40.222" style="s2">to identify the dark round<br />pulsatile popliteal artery.</p>
<p begin="00:00:40.222" end="00:00:43.492" style="s2">The compressible poplital<br />vein can be seen superior</p>
<p begin="00:00:43.492" end="00:00:45.695" style="s2">to the popliteal artery.</p>
<p begin="00:00:45.695" end="00:00:49.145" style="s2">The tibial nerve lies<br />superficial to the popliteal vein</p>
<p begin="00:00:49.145" end="00:00:52.668" style="s2">and appears as a bright<br />hyperechoic oval structure.</p>
<p begin="00:00:52.668" end="00:00:55.331" style="s2">The transducer should be slowly translated</p>
<p begin="00:00:55.331" end="00:00:57.926" style="s2">up the posterior thigh<br />to identify the point</p>
<p begin="00:00:57.926" end="00:01:00.976" style="s2">where the peroneal and tibial nerves join.</p>
<p begin="00:01:00.976" end="00:01:04.783" style="s2">The ideal point for needle<br />insertion is at or just below</p>
<p begin="00:01:04.783" end="00:01:07.763" style="s2">the split of the tibial<br />and peroneal nerves.</p>
<p begin="00:01:07.763" end="00:01:11.138" style="s2">The needles is advanced<br />using an in-plane technique.</p>
<p begin="00:01:11.138" end="00:01:14.455" style="s2">The needle is positioned<br />1 to 2 centimeters lateral</p>
<p begin="00:01:14.455" end="00:01:18.534" style="s2">to the transducer and<br />advanced under the transducer.</p>
<p begin="00:01:18.534" end="00:01:20.831" style="s2">The initial end point for<br />the needle is immediately</p>
<p begin="00:01:20.831" end="00:01:22.906" style="s2">beside the tibial nerve.</p>
<p begin="00:01:22.906" end="00:01:25.326" style="s2">Local anesthetic should<br />be principally injected</p>
<p begin="00:01:25.326" end="00:01:27.880" style="s2">around the tibial nerve,<br />as it is responsible</p>
<p begin="00:01:27.880" end="00:01:31.963" style="s2">for the majority of the<br />innervation of the foot.</p>