Agenesis of the posterior arch of the atlas

Torriani, Martin; Lourenço, José Leonardo Goes

doi:10.1590/s0041-87812002000200005

Cited by 42 publications

(58 citation statements)

References 10 publications

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“…However, the exact mechanism remains obscure. Congenital aplasia of posterior arch of atlas may be associated with several disorders including Down's syndrome, Turner syndrome, Gonadal dysgenesis, Arnold chiari malformation, Klippel-Feil syndrome, leading to atlantoaxial instability 2,3 . Hereditary factors may contribute to these anomalies, but the frequency is not known.…”

Section: Discussionmentioning

confidence: 99%

“…Complete fusion of posterior arch is expected to occur between 3 and 5 yrs of age. About 2% of fetuses presents fourth ossification center during development leads to i) median clefts of posterior arch, ii) Varying degrees of posterior arch dysplasia 2,3 . Defect of posterior arch of atlas is believed to occur due to failure of local chondrogenesis rather than disturbance of ossification 4 .…”

Section: Introductionmentioning

confidence: 99%

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Total aplasia of posterior arch of the atlas

Krupanidhi¹,

R²,

Mallikarjun³

et al. 2013

Int Jour of Biomed Res

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Total aplasia of posterior arch of the atlas

Krupanidhi¹,

R²,

Mallikarjun³

et al. 2013

Int Jour of Biomed Res

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“…Other abnormalities, including clefts of the anterior arch, atlantoaxial rotatory subluxation or hypertrophic downward projection of the posterior border of the foramen magnum, have been also described in the literature [5,9]. Flexion/extension views can demonstrate anterior displacement of the persistent tubercle and exclude atlantoaxial instability.…”

Section: Imaging Studiesmentioning

confidence: 97%

“…In other cases, such anomalies may be presented with transient neck pain or even different degrees of cord compression, including myelopathy [1,6]. Congenital aplasia or hypoplasia of the posterior arch of the atlas may be associated with several diseases, such as the Arnold-Chiari malformation, gonadal dysgenesis, Klippel-Feil syndrome, and Down and Turner syndromes [9].…”

Section: Clinical Presentationmentioning

confidence: 99%

Aplasia of the posterior arc of the atlas with persistent posterior tubercle: a case report

et al. 2004

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A 24-year-old man was admitted after a road traffic accident. He was a motorbike helmet-protected driver, riding at 50 km/h on a wet road, when the bike was hit by a car and skidded off the road. He was ejected from the bike and landed on the ground. When he arrived in the emergency department, he complained of pain at the back of his neck, but he had no neurological symptoms from the limbs. On physical examination, he had generalized tenderness over his cervical spine in the midline and slight restriction of flexion, without evidence of neurological signs. He had no other injuries to the locomotor system, the chest or to the viscera.Plain X-rays of his cervical spine revealed a free bony fragment in the lateral aspect of the posterior arc of the atlas that was initially interpreted as a fracture (Fig. 1). On detailed examination, the lesion was found to have smooth edges, whereas the posterior arc of the atlas could not be clearly visualized. A computed tomography scan of the C1/C2 region was therefore obtained, to further delineate the pathology. This confirmed the presence of posterior arch aplasia, a butterfly-shaped atlas and a persistent posterior tubercle. A helical-CT reconstruction with 1.5-mm-thick sections of the cervico-occipital region provided an additional perspective of this anomaly (Fig. 2). No evidence of involvement of neural structures was found. The patient was admitted for observation and reassessment. A Philadelphia collar was applied and nonsteroidal anti-inflammatory drugs (NSAIDs) were administered. The patient was asymptomatic the day after, and dynamic plain radiographs of his cervical spine, both in flexion and extension, were performed to assess the potential mobility of the bony fragment (Fig. 3). As the fragment was stable both in flexion and extension, and the patient did not develop neurological symptoms at any stage during follow-up (1 year), magnetic resonance imaging was not performed. Anatomic featuresThe atlas (C1) is anatomically divided into three parts; the anterior arch, the lateral masses and the posterior arch. Ossification begins from the two lateral masses at Abstract An unusual case of partial aplasia of the posterior arc of the atlas, with persistent posterior tubercle, is presented in a previously healthy individual who sustained a neck trauma. Both plain X-rays and CT findings specified the lesion. Dynamic X-rays in flexion and extension showed an immobile posterior tubercle. The patient did not develop neurological symptoms at any stage during follow-up (1 year).

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“…Other spine abnormalities have also been described to coexist with posterior arch defects: anterior arch clefts, atlantoaxial instability, cervical myelopathy or downward projections of the foramen magnum [3,4].…”

Section: Introductionmentioning

confidence: 99%

Posterior Arch Defects of the Atlas - A Report of Two Cases and Literature Review

Grazina¹

2017

MOJOR

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Agenesis of the posterior arch of the atlas

Cited by 42 publications

References 10 publications

Total aplasia of posterior arch of the atlas

Total aplasia of posterior arch of the atlas

Aplasia of the posterior arc of the atlas with persistent posterior tubercle: a case report

Posterior Arch Defects of the Atlas - A Report of Two Cases and Literature Review

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