The Hand

Phalanges | Metacarpals | Thumb | Paediatric fractures | Enchondroma

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Learning outcomes
  • Assess skeletal radiographs using a systematic approach
  • Understand the importance of obtaining the correct radiographic projections to demonstrate the thumb, metacarpals and phalanges
  • Describe metacarpal and phalangeal anatomy
  • Understand mechanisms of injury and the likely fractures/dislocations which may result
  • Search for subtle injuries and understand their clinical significance
  • Accurately describe dislocations and associated fractures
  • Understand common eponyms
  • Know the common avulsion sites and ligament injuries
  • Understand the paediatric Salter-Harris classification
  • Recognise and understand the relevance of common lytic lesions
Avulsion fracture at insertion of collateral ligament
  1. On the lateral view: anterior aspect - at the head or base of the phalanges or adjacent metacarpal (most commonly at the base of the middle phalanx). This is at the insertion of the volar plate (which refers to the joint capsule). This injury is caused by hyperextension:

Avulsion fracture at insertion of volar plate
  1. Again on the lateral, but on the dorsal aspect, at the insertion of the extensor tendon:

Avulsion fracture at insertion of extensor tendon
This tendon may rupture without an attached bone fragment and the resulting flexion deformity at the distal interphalangeal joint is called a mallet finger:

Mallet deformity
It is impotant to obtain a lateral view of the affected finger when injury to the phalanges is suspected, as an oblique does not demonstrate small avulsions or the extent of displacement of larger avulsion fractures:

Volar plate avulsion fracture of index finger ... no lateral
Dorsal dislocation PIPJ with avulsed fragment
Fracture distal shaft 5th metacarpal
Fracture base 5th metacarpal
Fractured 4th metacarpal, dislocation 5th carpo-metacarpal joint
Fracture-dislocation 4th/5th plus fractured hamate
Mechanism of injury is similar to the 5th metacarpal neck fracture so, when index of suspicion is high and a fracture to the head or neck isn't present, scrutinise the base of the 4th and 5th metacarpals, and the adjacent hamate.

Bennett's fracture-dislocation
Rolando's fracture-dislocation
Avulsion fracture at insertion of ulnar collateral ligament
Paediatric Fractures
Salter-Harris II
Salter-Harris III
Torus fractures
Enchondroma with pathological fracture

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