Radial extrinsic ligaments Radioscaphocapitate
arises from the volar lip of the radius and inserts on the waist of the lateral scaphoid, the waist of the capitate, and coalesces ulnarly with the ulnocapitate ligament to form the arcuate or deltoid ligament.
forms a sling over which the scaphoid bows into flexion during radial deviation;
radiocapitate ligament is the primary stabilizer of capitolunate joint, and is the primary stabilizer of the distal carpal row on proximal carpal row.
Long radiolunate (radiolunatotriquetral) ligament lies ulnar to the RSC ligament
arises from the volar lip of the radius and courses across the proximal pole of the scaphoid to attach to the volar lip of the lunate and then terminates on the triquetrum
Radioscapholunate: (ligament of Testut);
orignates from volar aspect of the interfossa ridge between scaphoid & lunate fossae & inserts into scapholunate interosseous ligament
is not a true extrinsic ligament of wrist
vascular structure devoid of any true collagen fibers and lacking structural integrity.
acts as neurovascular supply to scapholunate interosseous membrane and
Short radiolunate (SRL) ligament
arises from the radius adjacent to the lunate fossa and inserts on the volar lip of the lunate, coalescing with the LRL, ulnolunate, and volar lunotriquetral ligaments
believed to be one of the more important stabilizers of the lunate as it is the ligament that maintains the position of the lunate adjacent to the radius after a perilunate dislocation
Ulnar extrinsic ligaments ulnolunate
insert on the waist of the capitate and to join the RSC, forming an inverted V (arcuate ligament)
this is a key ligament along with the TFC;
- on occassion, may avulse from its insertion on the lunate, and this injury will allow dye extension both into the distal RU joint and into the mid-carpal joint;
Proximal row Intrinsic ligaments scapholunate interosseous ligament
C-shaped ligament attaching proximally from volar to dorsal
divided into 3 separate components
dorsal portion of this ligament supplies the majority of stabilizing strength to the scapholunate articulation.
central portion of the interosseous ligament is relatively thin and termed the intramembranous portion
lunotriquetral interosseous ligament
secures the articulation of the lunate and the triquetrum.
Like the SLIL, the LTIL is C shape and has 3 components – volar, intramembranous and dorsal
Unlike the SLIL, the volar portion is stronger
Distal row Intrinsic ligaments capitohamate ligament
composed of dorsal, deep, palmar, and longitudinal components.
The scaphotrapeziotrapezoidal (STT) joints are stabilized by a ligamentous complex that is both intrinsic and extrinsic in nature. These ligaments include the scaphotrapezial ligament, a scaphocapitate capsular ligament, and the dorsal and palmar STT capsular ligaments.
Space of Poirier
volar part of capsule of wrist has area of weakness, called space of Poirier;
lies between 2 ligamentous arcs
proximally – radiolunotriquetral
distally by radioscaphocapitate/ulnotriquetral (arcuate ligament) and triquetrohamatocapitate
area expands when wrist is dorsiflexed & disappears in palmar flexion;
rent develops during dorsal dislocations, & it is thru this defect that lunate displaces into the carpal canal in perilunar dislocations;
importance is dorsal radiocarpal ligament in rheumatoid arthritis
dorsal radiocarpal ligament
originates from the distal radius at Lister's tubercle.
deep fibers attach to the dorsal horn of the lunate and its superficial component courses to attach to the dorsum of the triquetrum.
dorsal intercarpal ligament
originates on the triquetrum
courses radially as it fans out to insert on the dorsal ridge of the scaphoid, the trapezium, and the trapezoid
deep portion of the DIC also augments the scapholunate and lunotriquetral interosseous ligaments.
Together, these two ligaments form a V, with the base of the V on the triquetrum. Between the limbs of the V is the less substantial dorsal wrist capsule which is useful for surgical exposures of the radiocarpal joint