L6.3 Wrist and hand joints

Question 1

Wrist joint

Answer 1

• condyloid joint
• Ligaments:
  
  • Med/lat collateral
  • Palmar/dorsal radiocarpal
  • Palmar/dorsal ulnocarpal
  • Palmar/dorsal radioulnar
    
    • The palmar/dorsal ligaments → have an oblique formation
      
      • Radius is concave ∴ carpal bones more likely to slip towards ulna, lig oblique to hold them
• Triangular fibrocartilaginous disc → at styloid process of ulna (btw ulna & carpal bones ∴ no contact)
• Ulna deviation > Radial deviation

Question 2

Intercarpal joint

Answer 2

• Glides between carpals
• Btw carpals in prox and distal rows
• Joint capsule same as carpometacarpal joints
• Ligament: ANT/POS interosseous lig (holds bones together)

Question 3

Midcarpal joint

Answer 3

• Functional joint, condyloid (permitted by concave-convex nature of bones)
• Btw prox and distal row of carpals
• Prox & distal as a unit each
• Flex & extend palm
• Radial deviation > ulna deviation

Question 4

CMC & IMC joints

Answer 4

• CMC: Synovial joint
  
  • 1st: saddle
  • 2nd & 3rd: Plane (immobile)
  • 4th & 5th: Hinge (F/E)
• IMC: plane joint
• Ligaments: CMC, IMC, interosseous, collateral

Question 5

MCP & IP joints

Answer 5

• MCP: condyloid: F/E, Ab/Ad
• IP: Hinge, F/E
• Ligaments:
  
  • Deep transverse MC lig (holds 2-5 digits tgt)
  • Plamar/dorsal volar plates
    
    • Tendons sit in btw → allows gliding
    • Lumbricals in btw → creates a modified hinge joint → allows slight rotation

Question 6

Finger injury: Skier’s Thumb

Answer 6

Skier’s thumb

Thumb has no transverse ligament → susceptible to injury
Med collateral lig ruptures (forced ab & ex)

Question 7

Finger injury: Swan-neck deformity

Answer 7

Swan-neck deformity

Palmar volar plates ruptures → excessive movment
PROX IP joint hyperextend; DISTAL IP joint compensation flexion

Question 8

Finger injury: Boutonniere deformity

Answer 8

Dorsal volar plate rupture
Opposite of swan-neck
PROX IP joint hyperflex; DISTAL IP compensation extension

Question 9

Finger injury: ‘Mallet’ Finger

Answer 9

Distal IP injury (from ball hitting distal phalange directly

Question 10

Common flexor sheaths

Answer 10

• Enclose: tendons of FDS + FDP (ulnar bursae), FPL (separate flexor sheath)
• Flexor sheaths then become digital synovial sheaths
  
  • Continuous for little finger

Question 11

Fibrous digital sheath

Answer 11

• Fibrous digital sheaths
  
  • Wrap around digital syno sheaths
  • Has annular & cruciform fibres
    
    • Volar plates beneath fibres

Question 12

What is tenosynovitis and tenovaginitis

Answer 12

Tenosynovitis: syno sheath infection
Tenovaginitis: Fibrous sheath infected

Question 13

Effects from nerve compressions

Answer 13

*Uses Tinel’s test: → tap nerve to elicit tingling sensation*

• Median N → PROX → hand of benefiction (1,2&3 can’t bend)
• Radial N → wrist drop
  
  • Distal compression → no effect, no dorsal palm muscles
• Ulnar N
  
  • PROX → Claw hand
  • DISTAL → handlebar neuropathy (excessive clawing)