Ultrasound of Ganglion Cyst & Wrist Anatomy Review

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