- See:
CMC arthritis
- Discussion:
- base of thumb metacarpal articulates w/ saddle shaped trapezium;
- saddle shaped articulation provides inherent stability;
- radial lateral ligament, which is covered by APL tendon, inserts into the thumb metacarpal;
-
deep anterior oblique ligament (palmar beak ligament);
- originates on the tuberosity of the trapezium & insertes on ulnar and volar edge of metacarpal base;
- anterior oblique ligament provides mobility but prevents dislocation;
- ligament maintains volar stability of saddle joint;
- anchors volar lip of first metacarpal to trapezium and second metacarpal;
- maximum tension occurs in this ligament with the metacarpal in flexion, abduction, and supination;
- traditionally, it is thought that insufficiency of this ligament leads to basal joint arthritis;
- ligament may help function as a pivot for the first metacarpal during palmar abduction to allow pronation;
-
dorsal radial capsular ligament
- is covered by EPB & EPL;
- some consider this ligament to be more important than the volar ligament;
- sectioning of this ligament produces dorsoradial subluxation of the thumb metacarpal;
-
ulnar ligament;
- limits range of abduction & extension of thumb;
- if this ligament is torn unopposed pull of APL & EPL & EPB muscles dislocates metacarpal shaft radially and proximally;
Functional anatomy of the CMC joint of the thumb.
JM Kauer. CORR Vol 220. 1987. p 220.
Osteoligamentous guidance of the movements of the human thumb.
BM Finn.
Am J. Anatomy. Vol 147. 1976. p 71.
Ligamentous stability of the base of the thumb.
T Pagalidis, K Kuczynshi, D Lamb.
Hand Vol 13. 1981. p. 29.
An anatomic study of the stabilizing ligaments of the trapezium and trapeziometacarpal joint.
PC Bettinger MD.
J. Hand Surgery. Vol 24-A. No 4. Jul 1999. p 786.
