What is the extensor retinaculum?

The extensor retinaculum is a thickened band of deep fascia on the posterior wrist that holds extensor tendons in place. It runs obliquely and attaches medially to the ulna and laterally to the radius.

What are the main functions of the extensor retinaculum?

Its primary functions are to maintain tendon alignment across the wrist, prevent bowstringing during wrist extension, and enable smooth movement via synovial sheaths.

How many compartments does the extensor retinaculum have, and what do they contain?

It has six compartments (I–VI) separated by septa. They contain extensor tendons and associated structures, such as APL and EPB in compartment I, and ED, EI, nerve, and artery in compartment IV.

Where does the extensor retinaculum attach?

It attaches medially to the ulna's styloid process, triquetral, and pisiform bones, and laterally to the anterior border of the radius.

What is the clinical significance of the extensor retinaculum's compartments?

The compartments organize tendons and neurovascular structures, helping prevent tendon displacement and reducing friction. This aids in diagnosing conditions like tendonitis or compartment syndromes.

How does the extensor retinaculum prevent bowstringing?

By holding tendons close to the wrist bones, it acts as a pulley system to keep them taut during extension, preventing them from pulling away and losing mechanical efficiency.

Extensor Retinaculum – Wrist Compartments Explained