HAND/WRIST
The use of musculoskeletal ultrasound (MSK-US) has rapidly expanded in the field of hand and upper extremity surgery. The ability to visualize soft tissue structures dynamically and in real time has made it an invaluable tool for both diagnosis and procedural guidance.
Ultrasound provides detailed imaging of the tendons, pulleys, ligaments, nerves, and small joints of the hand and wrist, all at the bedside. It has become particularly valuable for evaluating:
• Flexor tendon injuries – identifying partial vs. complete tears, flexor tendon adhesions
• Pulley injuries – assessing A2/A4 pulley integrity in athletes and climbers
• Nerve entrapments – including carpal tunnel syndrome (CTS) and ulnar neuropathy
• Soft-tissue masses – differentiating ganglion cysts, giant cell tumors, and lipomas.
One of ultrasound’s greatest advantages is the ability to evaluate pathology during movement:
• Snapping tricep tendon or ulnar nerve subluxation at the elbow
• Trigger fingers demonstrating A1 pulley catching
• ECU tendon subluxation at the wrist
This real-time evaluation provides diagnostic clarity that static imaging modalities often cannot.
Carpal Tunnel Syndrome
Carpal tunnel syndrome remains one of the most common compressive neuropathies of the upper extremity. Ultrasound offers a noninvasive, dynamic, and radiation-free way to both confirm the diagnosis and assess severity in replacement or conjunction with EMG/NCV studies.
Diagnostic Parameters
1. Median Nerve Cross-Sectional Area (CSA):
- Measured at the level of the pisiform (proximal carpal tunnel).
- A CSA ≥10 mm² is generally considered diagnostic of CTS in most populations.
- Sensitivity and specificity improve when comparing the CSA at the carpal tunnel to the forearm level, using a wrist-to-forearm ratio ≥1.4 as a diagnostic threshold. - (Reference: Fowler et al., J Hand Surg Am, 2014)
Procedural Guidance
Ultrasound-guided interventions have improved precision and outcomes in many common hand procedures:
• Carpal tunnel injections
Several randomized trials have shown that ultrasound-guided carpal tunnel injections yield superior short-term symptom relief compared to blind injections (Ustun et al., Am J Phys Med Rehabil, 2013).
• Trigger finger injections
• Small joint or tendon sheath aspirations/injections.
For hand surgeons, ultrasound has become an extension of the physical exam. Its dynamic, real-time capabilities allow for accurate diagnosis, guided intervention, and improved patient communication. As the technology continues to evolve, ultrasound will remain an essential component of modern hand surgery.
