- Transverse Retinacular Ligaments:
- anatomy:
- origin: edge of flexor tendon sheath at PIP;
- insetion: lateral edges of conjoined lateral bands
- function:
- prevents excessive dorsal shift of the lateral bands when the PIP extends;
- in flexion, they pull the lateral bands volarly over the PIP joint;
- pathology:
- attenuation of transverse retinacular ligament by laceration, rupture, synovitis, ect., leads to excessive dorsal position of lateral bands & secondary "Swan Neck Deformity"
- tightening of transverse retinacular ligaments along with attenuation or disruption of a triangular ligament leads to a positioning of the lateral bands volar to axis of PIP joint resulting in a boutonnere deformity;
- Oblique Retinacular Ligament:
- cord that runs from flexor tendon sheath at the proximal phalanx to the terminal extensor tendon;
- anatomy - oblique retinacular ligament
- origin - volar lateral crest of proximal phalanx;
- course - volar to axis of PIP joint
- insertion - lateral terminal extensor tendon;
- function:
- functional importance questioned;
- links motion of DIP and PIP joints;
- when PIP joint is flexed, ligament relaxes allowing DIP flexion;
- PIP extension tightens ligament facilitating DIP extension, thus theoretically linking motion of PIP and DIP joints;
- pathophysiology:
- may be involved with Dupuytren's contracture causing flexion of PIP joint and extension of the DIP joint;
- may be reconstructed, (SORL reconstruction) to facilitate DIP extension and prevent PIP hyperextension;
- contracture of oblique retinacular ligaments along w/ volar displacement of lateral bands cause boutonniere injury;
- test for ORL tightness:
- extend the PIP joint (which tightens the ligament) and then note resistance to passive DIP flexion (relative to when the PIP is flexed)
Anatomy of the oblique retinacular ligament of the index finger.
The spiral oblique retinacular ligament (SORL).
A systemic study of the oblique retinacular ligament of the human finger: its structure and function.