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Flashcards in Hand anatomy Deck (19):

Drawing and name a transverse section through the finger?

See diagram but name

  • terminal slip
  • Lateral band
  • Central band
  • Sagital Band
  • Lumbricals
  • Flexor digitorium profundus
  • Flexor digitorium superificialis

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What causes MCP Flexion?

  • 70% Interosseous
    • 3 Palmar inerosseous- adductors
    • 4 Dorsal Interosseous-abduct
    • origin mc shaft to base of prox phalanx+ extensor expansion
    • supply deep branch of ulnar nerve
  • 30% Lumbricals- attach to FDP distal and extensor proximally
    • lumbricals 1/2 =2/3 rd digit= median nerve- unipennate, from radial side FDP2/FDP 3
    • lumbricals 3/4= 4/5 digit= ulna nerve- bipennate, from radial side fdp3/4 (lumbrical3 ) and fdp 4/5 (lumbrical 4)

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What causes PIPJ and DIPJ extension?


  • Lumbricals ( via lateral band)
  • EDC Central slip
  • Dorsal interossei


  • EDC terminal tendon
  • Lumbricals via lateral bands 

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What causes extension at MCPJ?

Extensor digitorium communis (sagittal band)

  • Origin- lat epicondyle of humerus
  • Inserts- extensor expansions 4 digits- index-ring
  • also extends hand at wrist joint + MCPJ extension
  • innervation: PIN ( radial N)
  • blood s= Interosseous arteries


What flexes the PIPJ and DIPJ?

Describe their origin/insertion/Nerve and blood supplyDI?


Flexor digitorium superificalis (FDS)

Flexor digitorium profundus (FDP)


Flexor digitorium profundus (FDP)



origin- ant 3/4 proximal ulna, interosseous membrane,deep fascia of forearm. Thru carpal tunnel with FDS 

Inserts: thru fds inserts distal phalanx

innervation: 4/5 th digitis ulna, 2/3rd AIN ( medial)

origin- medial epicondyle humerus(common flexor origin)

inserts:ant margins of base of middle phalanges 2-4 fingers

Innervation : Median Nerve

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What does the retinacular ligament do ?


  • Retain and position the extensor mechanism during DIPj adn PIPJ flexion
  • Similar to sagittal band function

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Describe the components of retinacular ligament and their function?

  • Oblique Band- links motion of DIPJ and PIPJ from lateral volar proximal phalanx->dorsal terminal phalanx. when PIPJ flexes-> DIPJ flexes vis versa
    • Contracture-> volar displacment of lateral band-> Bountonniere
  • Transverse Band- with pipj flexion pulls lateral bands volarly over pip
    • attenuation lead to dorsal translation of lateral bands-> swan neck deformity



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Name the digital cutaneous ligaments?

  • Cleland's- 'Ceiling'
    • Dorsal to digital nerves, NOT involved in Dupytren's
  • Grayson's- 'Ground'-
    • Volar to digital nerves, involved in Dupytrens

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What is the funciton of digitial cutaneous ligaments?

  • Tether skin to deeper layers of fascia and bone to prevent excess movement of skin and improve grip
  • It also stabilses the NV bundle during flexion and extension


What is the function of the extension hood?

Allow extension of the PIPJ and DIPJ


What are the components of the extension hood?


  • Central slip- extends PIPJ- inserts base of middle phalanx
  • Lateral band- extends DIPJ-inserts distal phalanx formed from deep head of dorsal interossei and volar interossei combining

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What inserts into the lateral band?

  • Interossei- dorsal /palmar
  • lumbricals
  • Extensor incidis



What is the function of MCPJ collaterals?

  • Stabilise MCPJ during motion
  • Collaterals tight in flexion, loose in extension- as MCP flexes PIPJ further away so tightening ligaments


Describe the MCPJ collaterals?

  • Radial Collateral ligaments more horizontal than Ulnar Collateral ligaments
  • Each collateral has an accessory and proper ligaments
  • Accessory - more volar, tight in extension- add/abduction stress in extension
  • Proper- more dorsal, tight in 30o of flexion- add/abduction stress in 30o flexion


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What is the function of deep transverse metacarpal ligaments?

Where does it insert?

  • Prevents MC heads from splaying apart


  • Connects 2-5th MC heads together at volar plate

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What is the role of the Natatory ligament?

  • Resists abduction
  • Most superifical MC ligaments
  • origin- MC/MCPJ
  • inserts- prox phalanx of all 5 fingers
  • Involved in Dupytrens

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What is the function of the sagittal bands?

What is its orgin/ insertions?

  • Keep extensor mechanism tracking in midline during flexion of MCPJ
  • Origin- Palmar plate
  • inserts- dorsal extensor mechanism

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What is the traingular ligament's function?

  • counteracts pull of oblique ligament-preventing lateral subluxation of common extensor mechanism
  • located on dorsal side of extensor mechanism, distal to PIPJ
  • Triangular in shape

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what is the functon of the volar plate?

  • Prevent hyperextension
  • thickening of joint caspule at MC head and inserts into proximal phlanax via checkrein ligaments
  • tight in extension, loose in flexion

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