Dorsal Digital Expansion Of Thumb

作者：Joshi S S; Joshi S D; Athavale S A; Kishve P S; Jadhav S D

来源：Journal of the Anatomical Society of India, 2008, 57(2): 135-139.

• Thumb
• dorsal digital expansion
• extensor pollicis longus
• extensor pollicis brevis
• adductor pollicis
• abductor pollicis brevis

Human hands perform the complicated functions of gripping, pinching, feeling and expressing. All these activities depend on the coordinated actions of the thumb and the fingers. The functional importance and the complexity of movements of thumb are well reflected in an extensive representation of thumb in the brain. The extensor apparatus of thumb displays obvious structural variations in its proximo-distal expanse. There is no unanimity amongst various authors on the anatomy of dorsal digital expansion (DDE) of thumb. Some (Schafer et al, 1923; Sinnatamby, 1999) are of the view that there is no extensor expansion of the thumb. Variations are described in the contributions made by various elements which go into the formation of DDE. We have undertaken a detailed study of formation and attachment of DDE of thumb in 110 upper limbs (Rt-55, Lt-55) available in the department. DDE of thumb was present in all the limbs examined. It was triangular in shape. The anchoring fibers were well defined in the form of a hood over the dorsal surface of metacarpophalangeal (MP) joint. Medial margin of the expansion was well defined in all the cases; whereas, the lateral margin was variably developed. In 68% of thumbs the lateral margin of DDE was contributed by abductor pollicis brevis (APB) out of these in 60% this margin was well defined. In 98% cases the oblique head of adductor pollicis (AP) contributed fibres to medial margin of DDE. In 62.7% fibres of first palmar interosseous could also be traced to the medial margin.
The mechanism of DDE permits for greater variations in extension of various joints of thumb then would have been possible in its absence.

• 出版日期2008-12
• 单位河北医科大学