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18 Cards in this Set
- Front
- Back
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The Distal Radioulnar Joint involves the radius, ulna, and
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the interosseus membrane
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fiber types of IOM
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Oblique A & Oblique B
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OA Fibers are important in
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WB and supination
distal ulna to proximal radius increase tension in WB & supination |
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OB Fibers are important in
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Radial Txn
proximal ulna to distal radius increase tension with radial traction & pronation |
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WBing F goes through what
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2 bones: ulna & radius
not the IOM |
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IOM is maximally tensioned at
--most relaxed at |
0-5 dd supination
most relaxed in full pronation/full supination bc UH pushes radius away - distal & radial rotation helps to clear biceps T for pronation |
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functions
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almost no nociceptors - no pain
optimize ability to carry transfer of load system: valgus elbow = min load transfer most tense in varus |
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plane of Rx is always
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perpendicular to dorsum of hand & wrist
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DRUJ
arthrokinematics |
distal radius = concave
distal ulna = convex |
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DRUJ
2ry osteokinematic motions |
pronation = volar radius translation
supination = dorsal radius translation |
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DRUJ Capsule
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lax / loose + synovial membrane
high level of mobility there not directly controlled by MM CP: Pain @ end ROM |
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TFCC at DRUJ
1ry source of stability to DRUJ |
radioulnar disc and continuation of the articular cartilage of the distal radius
extension of distal radius bt radius and ulna, radius & prox wrist, bt ulna & triquetrum --transmits load through ulna --if radius fx=>TFC tension=>TFC lesion (ulnar side of wrist) |
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TFCC vascular / nerve supply
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outer - type 1 collagen for tension loading - more vascular/innervation, better chance of healing
inner - type 2 for compression - less vascularized/innervated think: compression on inside expands to create tension on outside |
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TFCC complex
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more specific on ulnar side -- more so to ulna than radius
-TFC acts as keystone -acts in concert with UCL for stability -ulnocarpal LL enhance support -ECU sheath is an additional contributor to support |
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UCL and the TFCC
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UCL has 2 divisions - originated from styloid process
trauma affects/irritates only one part of it UCL is not a true collateral 2ry to increased motion: needs dynamization 1) dorsal carpus w/ ECU + disc 2) palmar carpus w/ FCU |
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other functions of TFCC
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controls pronation & supination
controls both rotation & translation of R on U increases congruency bt carpus & distal ulna increases stability of DRUJ & UCL to produce smooth motion |
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TFCC Load Transmission
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normal case:
--83% load transmitted through radius (most F through R) --17% through TFCC or ulna with discectomy - post-op: --95% trasmitted through radius --increased likelihood for degeneration in R & C columns --more likely to fail when add 12% to other side |
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TFCC Complex
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Dorsal branch taut in Supination
orientation allows LL to relax in Neutral Palmar branch taut in Pronation |
