<prompt> All of the following are true about fracture of the atlas veebra, except:Jefferson fracture is the most common typeQuadriplegia is seen in 80 casesAtlantooccipital fusion may sometimes be neededCT scans should be done for diagnosis  <response>: B i.e. Quadriplegia is seen in 80 cases Jafferson fracture is burst fracture of ring of atlas Cl veebraeQ. In most cases it doesnt leads to neurological deficitQ. With the exception of pain or loss of sensation in the greater occipital nerve distribution neurological sequelae are uncommon and more likely to be related to associated injuries. It is most common type of atlas fractureQ. It is cause by axial compression forceQ with or with out extension force, resulting from a fall on the head from a height or mass falling on head. This mechanism of injury results in a burst fracture of ring of atlas C1 veebraeQ, that occurs secondary to the occipital condyles being driven into the interior poions of the ring of atlas and driving the lateral masses outwards. Lateral displacement of C1 lateral mass lateral the outer coex of the C2 lateral mass raises concerns for the structural integrity of the transverse atlantal ligament TAL. The stability of atlas depends on TAL. Due to outward movement of lateral masses, there is no encroachment on the neural canal and, usually, no neurological damageQ. Classical Jaffersons fracture as described by Jafferson in 1920 was four pa fracture of ring of atlasQ 2 pa of anterior ring 2 pa of posterior ring. However more common are two pa or three pa fractures. It is tyically diagnosed on plain radiographs - pen mouth odontoid view may show asymmetry of the lateral masses of C1 on C2 with overhang. - A bilateral overhang 6.9 mm suggest disruption of transverse ligament and potential late instability. - On lateral radiograph presumptive evidence of transverse ligament disruption is 4mm atlanto-dens interval. Coronal C T reformation provides the best method of evaluating impoant atlas fracture characteristicsQ. The treatment for isolated atlas injuries is typically nonoperative - Undisplaced stable injuries are managed by semi rigid cervical collar or halo- vest until fracture unites. - Unstable injury wit transverse ligament rupture 7mm displacement of lateral mass is managed by halo traction fb halovest immobilization for a total of 3 - 4 months. - If a late instability or nonunion is present, atlanto - axial C1 - C2 ahodesis and atlanto - occipital cervico- occipital fusionQ. is done Fracture of atlas are associated with injury elsewhere in cervical spine in upto 50 of cases; odontoid fractures and hangmans fractures in paicular should be excluded. 