No, 3rd Dorsal Compartment Discomfort Does Not Cause De Quervain's Tenosynovitis
De Quervain's tenosynovitis is a distinct pathology of the first dorsal compartment of the wrist, not the third dorsal compartment, and these are separate anatomical entities that do not cause one another.
Anatomical Distinction
De Quervain's tenosynovitis specifically involves stenosing tenosynovitis of the first dorsal compartment, which contains the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons 1, 2. The third dorsal compartment contains the extensor pollicis longus tendon and is anatomically separate from the first compartment 3.
Understanding the Pathophysiology
- De Quervain's disease results from non-inflammatory thickening of the tendinous sheath in the first dorsal compartment, leading to entrapment and increased friction of the APL and EPB tendons 1
- The condition is characterized by pain and tenderness specifically over the radial styloid at the first extensor compartment 2
- Anatomical variations within the first compartment itself—such as subcompartmentalization (present in 62.2% of De Quervain patients) and variations in tendon slip numbers—are relevant to the pathophysiology, not involvement of other compartments 4, 5
Important Differential Diagnosis Consideration
While the third dorsal compartment does not cause De Quervain's, you should be aware of intersection syndrome (also called distal intersection tenosynovitis), which can present with wrist pain and involves the crossing point where the first dorsal compartment tendons (APL and EPB) cross over the second dorsal compartment tendons 3. This is a distinct entity from De Quervain's and should be included in your differential diagnosis 4.
Clinical Pitfall to Avoid
Do not confuse anatomical proximity with causation. The dorsal compartments of the wrist are separate anatomical structures, and pathology in one compartment does not cause pathology in another. If a patient has pain in both the first and third dorsal compartments, consider these as separate pathologies requiring individual assessment rather than one causing the other 3, 4.