Chapter 1: Functional Anatomy and Biomechanics - Wrist and Hand Region

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Chapter 1: Functional Anatomy and Biomechanics - Wrist and Hand Region
2015-03-08 19:14:11
Wrist Hand Region
NPTE: Chapter 1
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  1. Radiocarpal Joint
    • Dorsal radiocarpal: limits flexion, pronation and possibly radial deviation
    • Convex scaphoid and lunate articulate ith concave radius
  2. Midcarpal Joint
    • Articulation between 4 proximal and 4 distal carpal bones
    • Functional rather than anatomical joint
    • Divided into middle pillar (lunate and triquetrum with capitate and hamate) and lateral pillar (scaphoid with trapezoid and trapezium)
  3. CMC Joint
    • 1st CMC (thumb) = saddle articulation with trapezium being convex in medial/lateral direction and concave in ant/post directio
    • 1st met opposite in shape to trapezium
    • 2nd-5th CMC are essentially flat between bases of mets and distal row of carpals 
  4. MCP Joint
    Convex MCP with concave prox phalanges
  5. IP Joints
    • (PIP and DIP)
    • Convex distal aspects prox phalanges with concave proximal aspects of middle phalanges 
  6. Finger Ligaments: Collaterals
    • Run separately from lateral condyle --> distal phalanx and lateral volar plate at each MP, PIP, and DIP joint
    • Tighten with flexion (all fibers)
    • Volar fibers tighten with extension
  7. Finger Ligaments: Accessory 
    Run from condylar head to volar plate
  8. Finger Ligaments: Transverse 
    • Present at MCP joints
    • Provide stability linking MCP joints and provide reinforcement to ant capsule 
  9. Wrist Ligaments
    • Radial Collateral = limits ulnar deviation
    • Ulnar Collateral = limits radial deviation
    • Palmar Ulnocarpal = limits ext and supinatin
    • Palmar Radiocarpal = limits ext and supinatio through knuckles
  10. Extensor Hood
    • Fibrous mechanism on the dorsum of each finger
    • Fibrous expansion of extensor digitorum tendon
    • Assists with extension of PIP and DIP joints
  11. Volar Plate
    • On palmar aspect of MCP, PIP, and DIP joits
    • Thickening of capsule
    • Increases articular surface during extension and protects joint volarly
    • More mobile @ MCP than at IPs
  12. 1st CMC Biomechanics
    • Flex/Ext = concave on convex
    • Abd/Add = convex on concave
    • Flex and abd = 1st met rotates ulnarly
    • Ext and add = 1st met rotates radially
  13. PIPs, DIPs, and MCPs Biomechanics
    During flexion, digits rotate radially to enhance grasp and opposition
  14. Wrist Biomechanics
    • Flexion: prox aspect of scaphoid/lunate glide dorsally relative to radius
    • Extension: prox aspect of scaphoid/lunate glide ventrally relative to radius
    • Radial Deviation: prox row glides ulnarly, prox surface of scaphoid rotates palmarly
    • Ulnar Deviation: prox row glies radially as a unit