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At least 163 records · Page 9Linked to original sources
PubMed1979

Management of chronic atlantoaxial dislocation.

Twenty-two patients with chronic atlantoaxial dislocation have been treated. Of 13 patients with a reducible dislocation by skeletal traction, 12 underwent successful posterior infusion of the first, second and third cervical vertebrae. Of nine patients with irreducible dislocation, eight underwent surgical reduction and fusion through the transoral approach. The reduction was successful in all eight, but fusion was accomplished in four.

Adolescent↗
PubMed1998

Fracture of the axis after dome-like cervical laminoplasty.

We describe a case of fracture of the axial neural arch that occurred after a dome-like cervical laminoplasty and caused dural compression. Cervical laminoplasty with dome-like laminoplasty of the axis was performed on a patient with cervical myelopathy due to ossification of the posterior longitudinal ligament extending from C2 to C6. After temporary neurological remission, the patient experienced unanticipated neurological deterioration with posterior cervical pain. Radiographs, magnetic resonance imaging and computed tomography of the cervical vertebrae showed a fractured axial lamina that was compressing the cervical cord. After total axial laminectomy, permanent neurological improvement was obtained. Our experience suggests that care should be taken to avoid an excessive dome-like laminoplasty and that the possibility of axial fracture should be borne in mind.

Aged↗
PubMed1979

Morphological and functional studies on the odontoid process of the human axis.

Studies on the morphology of the odontoid process by various methods strongly suggest a functional adaption of this bony element. With regard to the inclination of the dens axis and the varying position of its articular facets, a modified trabecular system can be observed. Photoelastic experiments confirm that these modifications are correlated with two specific kinds of mechanical stress. The straight odontoid process is only subjected to stress due to compression, but the dorsally inclined dens to bending stress. Based on the morphological and experimental findings, flexion and extension between the first and second vertebrae (in addition to rotation as the principle movement) are discussed.

Adaptation, Biological↗
PubMed1995

Quantitative anatomy of the second cervical vertebra.

STUDY DESIGN: While the gross anatomy of the second cervical vertebra has been well described qualitatively, our evolving understanding of spinal pathology makes it necessary for the modern surgeon to have more quantitative information. OBJECTIVES: The authors' goal was to directly measure clinically relevant dimensions of the second cervical vertebra, using a collection of anatomic specimens. SUMMARY OF BACKGROUND DATA: Many existing studies have been based on analysis of radiographic images, which are subject to errors of magnification, rotation, and projection. Several recent studies of dens morphology have been based on direct measurements. These studies in general did not extend to the lateral masses or posterior ring, however. METHODS: Direct measurements using digital calipers and goniometer were taken from 51 dried human second cervical vertebrae. The maximum and minimum anteroposterior and lateral diameters of the dens, and the anteroposterior and lateral diameters of the end-plate and foramen and were measured. The heights of the dens and superior facet surfaces were measured relative to a plane defined by the anterior-most point of the inferior endplate and the inferior-most points of the inferior facet surfaces. RESULTS: The greatest variation was found in the dens angle, with specimen dens angles ranging from -2 degrees to 42 degrees. The most significant correlations were between the total height of the vertebra and the height to the base of the dens (r2 = 0.81), between the total height of the vertebra and the maximum lateral diameter of the dens (r2 = 0.77), and between the minimum lateral diameter of the dens and the maximum lateral diameter of the dens (r2 = 0.63). CONCLUSIONS: The dimensions measured in this study confirm a significant degree of anatomic variation in the second cervical vertebra, and show no important correlations among the various measured dimensions. In particular, no significant correlation was found between dens height and canal diameter. Dens angle in the sagittal plane was the most variable measurement.

Axis, Cervical Vertebra↗
PubMed1993

Hoxb-4 (Hox-2.6) mutant mice show homeotic transformation of a cervical vertebra and defects in the closure of the sternal rudiments.

Two Hoxb-4 (Hox-2.6) mutations were introduced into the mouse germline. The overt phenotype caused by one of the mutations was assayed on two different genetic backgrounds, an inbred 129SvEv and a hybrid 129SvEv-C57BL/6J. The allele hoxb-4' is a disruption of the first exon and causes two obvious skeletal changes: a partial homeotic transformation of the second cervical vertebra from axis to atlas and a defective morphogenesis of the sternum. Both phenotypes have incomplete penetrance and variable expressivity when assayed in the hybrid genetic background, but the sternum defect is completely penetrant in the inbred background. The mutant allele hoxb-4s has a premature stop codon, introduced by the "hit and run" method in the second exon, that disrupts the third helix of the homeodomain. This allele also causes the partial homeotic transformation of axis to atlas, but it does not affect the sternum.

Animals↗
PubMed1990

Os odontoideum detected on a lateral cephalogram of a 9-year-old orthodontic patient.

A 9-year-old girl was seen for routine orthodontic care. The lateral cephalogram revealed an irregularity, os odontoideum, of the second cervical vertebra. The patient was referred to a pediatric orthopedist, and subsequent surgical correction was accomplished without complications. This condition has significant implications for the spinal cord at the level of C1 and C2. Phase I orthodontic care proceeded normally.

Axis, Cervical Vertebra↗
PubMed2002

Hangman's fracture caused by suspected child abuse. A case report.

This report highlights the difficulties associated with diagnosing cervical spine injuries in children especially as the history and mechanism of injury may often be unclear and the normal variations in roentgenographic appearance may be confusing. As far as we are aware this is only the second case of traumatic Hangman's fracture in a child under the age of 3 years and the only case where there is a strong probability of child abuse. A female child aged 23 months was admitted with a 5-day history of irritability and general malaise. Her father reported noticing that she was reluctant to move her neck. He denied any possibility of trauma. On admission she had neck stiffness with a temperature of 37 degrees C and supported her neck with her hands. There was evidence of otitis media of her right ear. Her physical examination was otherwise normal. A full blood count and lumbar puncture were within normal limits. Cervical spine x rays suggested a Hangman's fracture of C2 with slight anterior subluxation of C2 on C3 and a kyphus at that level. Computerized Tomography demonstrated no significant canal encroachment. An isotope bone scan was non-diagnostic. She was treated in a moulded cervical collar with neck held in slight extension. Her symptoms resolved and further radiographs showed improved alignment. Repeat CT scans seven weeks post admission showed callus formation. At follow-up at one year she remains asymptomatic. Hangman's fracture is very rare in children under 3 years and the considerable normal variations further complicate diagnosis. Swischuk described the posterior cervical line connecting the spinous process of C1-C3 vertebrae on the lateral projection to differentiate a true fracture dislocation from physiological anterior displacement. A detailed history, roentgenograms, bone scans, CT scans and MRI scans are often required for accurate diagnosis.

Axis, Cervical Vertebra↗