Anatomic study of the first extensor compartment and the relationship between the extensor tendon width and its...

Area of Science:

• Anatomy
• Orthopedics
• Surgical Anatomy

Background:

• The extensor pollicis brevis (EPB) tendon typically inserts at the base of the thumb's proximal phalanx.
• A distal EPB tendon insertion near the interphalangeal joint is observed in some de Quervain's disease cases.
• Anatomical variations in EPB tendon insertion may contribute to thumb pain and dysfunction.

Purpose of the Study:

• To investigate the relationship between extensor pollicis brevis (EPB) tendon width and its insertion point.
• To test the hypothesis that EPB tendons are wider in individuals with an extended EPB.
• To evaluate anatomical variations of the EPB tendon in relation to de Quervain's disease.

Main Methods:

• Dissection of the first extensor compartment in 45 adult cadaveric hands.
• Assessment of the intertendinous septum and EPB tendon insertion point.
• Measurement of extensor tendon width at the proximal phalanx midpoint.

Main Results:

• An extended EPB tendon was found in 51.1% of cases.
• The mean extensor tendon width was significantly greater in the extended EPB group (cut-off 7.12 mm).
• No significant sex-based differences were noted for extended EPB or intertendinous septum presence.

Conclusions:

• Wider extensor pollicis brevis (EPB) tendons are associated with extended EPB variations.
• EPB tendon width differences can aid in identifying anatomical variations.
• These findings contribute to understanding thumb tendon anatomy relevant to de Quervain's disease.