In this radiology lecture, we review the ultrasound appearance of ganglion cysts while highlighting relevant wrist ultrasound anatomy! Key teaching points include: * Ganglion cysts are viscous, mucin-filled collections lacking a synovial lining * Most commonly occur at hand/wrist = Most common wrist mass * Location: Dorsum of wrist (60%), frequently adjacent to scapholunate ligament; volar wrist (20%), often between radial artery and flexor carpi radialis tendon; flexor tendon sheath (10%); associated with DIP joint (10%) * Grows out of tissues surrounding joint like a balloon on a stalk. May see a pedicle connecting to joint * Usually well-defined and multilocular, can be unilocular * Hypoechoic to anechoic with posterior acoustic enhancement * Noncompressible: Dorsal joint recess and bursal collections will typically collapse with transducer pressure or wrist movement * Typically no vascular flow, but septations may have vascularity. May see pulsation artifact from adjacent radial artery * Volar cysts can extend towards median nerve and may cause carpal tunnel syndrome * May displace or envelop radial artery * Tx: Watchful waiting, percutaneous US-guided aspiration and steroid injection, excision * Lister’s tubercle is a useful landmark for dorsal wrist anatomy * Relevant dorsal extensor tendons (from radial side to ulnar): Compartment 2 = Extensor carpi radialis longus, extensor carpi radialis brevis, Compartment 3 = Extensor pollicis longus (on ulnar side of Lister’s tubercle), Compartment 4 = Extensor digitorum and extensor indicis * Flexor carpi radialis overlies the ventral aspect of the scaphoid bone * Pisiform and scaphoid bone form the proximal “twin peaks” of the carpal tunnel at the ventral wrist crease * Median nerve diameter increase of 2 mm2 or more = Significant compression To learn more about the Samsung RS85 Prestige ultrasound system, please visit: https://www.bostonimaging.com/rs85-prestige-ultrasound-system-4 Click the YouTube Community tab or follow on social media for bonus teaching material posted throughout the week! Spotify: https://spoti.fi/462r0F2 Instagram: https://www.instagram.com/Radquarters/ Facebook: https://www.facebook.com/Radquarters/ Twitter: https://twitter.com/Radquarters Reddit: https://www.reddit.com/user/radiologistHQ/