Pars interarticularis

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Cervical vertebra.

The pars interarticularis, or pars for short, is the part of vertebra located between the inferior and superior articular processes of the facet joint.[1]

In the transverse plane, it lies between the lamina and pedicle. In other words, in the axial view, it is the bony mass between the facets that is anterior to the lamina and posterior to the pedicle. It is abnormal in spondylolysis, either due to fracture or congenitally.[2] Bilateral C2 pars fractures are known as the hangman's fracture.

On an anterior oblique radiograph of the lumbar spine, the pars is the neck of the imaginary Scottie dog; the Scottie dog's eye is the pedicle,[3] its hindlegs the spinous process, its nose the transverse process, its ear the superior articular facet and its forelegs the inferior articular facet.[4]

Stress fractures of the pars interarticularis are known to be associated with playing volleyball, although the mechanism is somewhat unclear.[5]

See also[edit]

References[edit]

  1. ^ Pars+interarticularis at eMedicine Dictionary
  2. ^ spondylolysis at eMedicine Dictionary
  3. ^ Macleod S, Hendry G (1982). "Congenital absence of a lumbar pedicle. A case report and a review of the literature". Pediatr Radiol 12 (4): 207–10. PMID 6752854. 
  4. ^ Capobianco JD. OMM Board Review. Available at: www.md-do.org. Accessed on April 9, 2007.
  5. ^ emedicine.medscape.com

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