Annular ligaments of fingers
| Annular ligaments of fingers | |
|---|---|
Phalanx | |
| To | Phalanx |
| Identifiers | |
| Latin | ligamentum anulare digitorum pars anularis vaginae fibrosae digitorum manus |
| Anatomical terminology] | |
In
human anatomy, the annular ligaments of the fingers, often referred to as A pulleys, are the annular part of the fibrous sheathes of the fingers
.
Four or five such annular pulleys, together with three deep and superficial flexor tendons. The annular and cruciate ligaments serve to govern the flexor mechanism of the hand and wrist, providing critical constraints to the flexor tendons to prevent bowstringing upon contraction and excursion of extrinsic flexor musculo-tendinous units.[1]
The first annular pulley (A1 pulley), near the head of the
metacarpal bone, lies in the flexor groove in the deep transverse metacarpal ligament.[2]
In the thumb there are two annular pulleys and a single oblique pulley.
[2]
Together, the A pulleys form a continuous tunnel and, because each A pulley's attachments on the bone is wider than its roof, its shape prevents the pulley from pinching its neighbours at extremes of flexion. The short roof also minimises pressure on the tendon under tension, instead distributing pressure throughout the tunnel. [2]
Notes
- ^ S2CID 22056119.
- ^ a b c Austin 2005, pp. 326–8 ("Mechanisms of Finger Flexion")
References
- Austin, Noelle M. (2005). "Chapter 9: The Wrist and Hand Complex". In Levangie, Pamela K.; Norkin, Cynthia C. (eds.). Joint Structure and Function: A Comprehensive Analysis (4th ed.). Philadelphia: F. A. Davis Company. ISBN 0-8036-1191-9.
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