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PubMed2005

[Upper cervical spine injuries and their diagnostic features].

The upper cervical spine includes the articulations of the occiput with atlas and the atlas with the axis, as well as the bony structures of the base of the skull, axis, and atlas. The unique anatomy of the upper cervical spine and the typical mechanisms of injury yield a predictable variety of injury patterns. Injuries to this area include occipital condyle fractures, occipitoatlantal dislocations, subluxations and dislocations of the atlantoaxial articulation, atlas fractures, odontoid fractures, and fractures of the arch of the axis. Injuries to this region are relatively common and can be easily overlooked because patients with the upper cervical injury may have an associated head injury, which can alter their level of consciousness and complicate obtaining an accurate history and physical examination. The complex regional anatomy and overlying structures make plain radiographic images difficult to interpret. Delayed recognition can result in significant disability. A thorough understanding of the clinical presentation, radiographic assessment, and mechanisms of injury can minimize morbidity and enhance treatment effectiveness for the more common upper cervical ligamentous and bony injuries.

Atlanto-Axial Joint↗
PubMed1979

The rotational component in the dynamics of the C2-3 spinal segment.

The technique of the PA axial projection of the arches of the upper cervical vertebrae into the occipital foramen and the normal findings, are described. The influence of maximum forced anteflexion at the craniocervical junction and rotation of the head on the relations of atlas and axis is demonstrated. It seems that in this position rotation at atlas-axis level is restricted and partly transmitted to the C2-3 segment. Thus, selective clinical examination of the rotational component of the dynamics at C2-3 can be achieved and the pathological restrictions of movement can be assessed.

Axis, Cervical Vertebra↗
PubMed2003

Relationship between alignment of upper and lower cervical spine in asymptomatic individuals.

OBJECT: The aim of this study was to establish standard values for the normal alignment of the upper cervical spine and to clarify its relationship with the lower cervical spine in terms of alignment METHODS: Three hundred thirteen asymptomatic volunteers (155 men and 158 women) participated in this study. Lateral radiographs were obtained with the neck in neutral position, and the angles formed by the occiput (Oc) and the axis, the atlas and the axis, and C-2 to C-7 were measured. The mean Oc-C2 angle was 14.5 +/- 8 degrees in men and 16 +/- 8.5 degrees in women; the mean C1-2 angle was 26.5 +/- 7 degrees and 28.9 +/- 6.7 degrees, respectively; and the mean C2-7 angle was 16.2 +/- 12.9 degrees and 10.5 +/- 10.3 degrees, respectively. Although weak, statistically significant negative correlation was observed between Oc-C2 and C2-7 angles (r = -0.31 in men and -0.37 in women), and between C1-2 and C2-7 angles (r = -0.22 in men and -0.22 in women). The correlation coefficient between the Oc-C2 and C2-7 angles was greater than that between the C1-2 and C2-7angles. CONCLUSIONS: Such relationships between alignment of the upper and lower cervical spines should be taken into consideration when performing occipitocervical fusion.

Adolescent↗
PubMed1983

Traumatic neuropathy of second cervical spinal nerves.

The second cervical spinal nerves are unduly vulnerable to forcible approximation of the arches of the atlas and axis and to excessive rotation of the atlas on the axis. Sequelae of such injury include sensory aberrations ranging from loss of feeling to severe neuralgia and disorders of balance. Diagnosis of second cervical neuropathy may be difficult when there are multiple injuries to the cervical spine, but most cases clear up spontaneously within one to three years.

Accidents, Traffic↗
PubMed1998

The effect of atlas anterior translation and rotation on axis canal size. A computer-assisted anatomic study.

Eighteen adult paired atlas and axis specimens were used in conjunction with computer analysis to determine the average transverse canal area of the axis after different degrees of anterior translation and three types of rotation of the atlas. After each displacement, the remaining transverse canal area of the axis was calculated. The data showed that the mean transverse canal area of the axis was 351.5 +/- 8.8 mm2 for males and 276.9 +/- 8.6 mm2 for females, respectively. After a 3-, 4-, and 5-mm anterior translation of the atlas, the mean transverse canal area of the axis decreased to 300.4 +/- 5.1 mm2 (85.5%) for males and 238.0 +/- 2.1 mm2 (85.9%) for females, 283.9 +/- 5.9 mm2 (80.8%) for males and 228.5 +/- 3.1 mm2 (82.5%) for females, and 260.4 +/- 4.2 mm2 (74.1%) for males and 216.4 +/- 2.8 mm2 (78.2%) for females, respectively. After a 40 degree rotation, 40 degree rotation with 4-mm anterior translation, and 40 degree rotation with 8-mm anterior translation of the atlas, the mean transverse canal area of the axis for both sexes decreased approximately to 58%, 42%, and 23%, respectively. This study confirmed that the size of the transverse canal area of the axis was consistently correlated with the degrees of the anterior translation and rotation of the atlas.

Adult↗
PubMed1989

[The measurements of the clivus, the foramina on the external base of the skull and the superior vertebrae].

Anatomical measurements are made on the clivus and the upper cervical column. These values are important for transoral, transpalatinal approaches to the clivus and to atlas and axis. The mean-values of the length of clivus in adults were 45 mm on the internal cranial base, on the external the length between the basion and the vomer was estimated with 27.9 mm, the tuberculum pharyngeum is situated on our material 11.2 mm rostral of the basion. The anterior part of clivus in the external cranial base has a width of 22.5 mm, the posterior part has one of 42.8 mm. Included are measurements of the hypoglossal canal and measurements of foramen lacerum externum. The postnasal enlargement of the most portals of the cranial base is given in Fig. 5. The occipital condyles are 22.9 mm in length, the angle between the condyles was 51.4 degrees. The thickness of clivus was 18.3 mm in a level 28 mm rostral of basion and 9.3, 11 mm rostral of basion. Given are also the thickness of substantia corticalis of clivus and the area of posterior wall of sphenoid sinus. Measured are also the distances between dens axis and anterior arch of atlas and basion. The height of anterior arch was found larger than by other researchers. Included are length and width values of the upper cervical column and the insertion areas of the longus capitis and rectus capitis anterior muscles.

Cervical Vertebrae↗
PubMed1983

Pseudospread of the atlas: false sign of Jefferson fracture in young children.

Jefferson fractures are rare prior to teen-age. Three young children examined after trauma exhibited the characteristic spread appearance of the atlas, but fractures were excluded radiographically and clinically. A retrospective study demonstrated a similar appearance, termed "pseudospread," in most children aged 3 months to 4 years, including over 90% during the second year. Pseudospread results from a discrepancy between the "neural" growth pattern of the atlas and the "somatic" pattern of the axis. An "atlas spread index" is defined and a normal range presented. When an atlas fracture is suggested by apparent lateral spread of the lateral atlas masses, computed tomography is useful to demonstrate an intact atlas ring.

Axis, Cervical Vertebra↗
PubMed2005

Management of acute traumatic atlas fractures.

OBJECTIVE: A prospective review of a clinical series was performed. The treatment features of atlas fractures with and without associated axis injuries were investigated. METHODS: Twenty-nine patients were investigated. RESULTS: No displaced fractures were treated with a cervical orthosis. Patients with displaced fractures were managed with a halo vest immobilization; 96.4% patients had a solid fusion at their last follow-up evaluations. CONCLUSIONS: Isolated not displaced or combined with not displaced axis fractures atlas fractures can be treated effectively with a rigid cervical collar alone. Isolated displaced fractures or not displaced but with concurrent displaced axis fractures require immobilization by the halo vest.

Adolescent↗
PubMed1988

Laminectomy for relief of atlantoaxial subluxation in four horses.

Malalignment of the atlas and axis was seen in 4 horses with an idiopathic form of atlantoaxial subluxation characterized by spinal cord compression on extension. The bone structure and density of the atlas and axis were radiographically normal in 3 of the 4 horses. Clinical signs appeared when the horses were 6 to 30 months old, and 3 of the 4 horses had a history of trauma. Although a congenital anomaly could not be ruled out, the cause was thought to be trauma. The horses were moderately to severely ataxic at the time of examination. Myelography revealed compression of the spinal cord at the atlantoaxial junction on extension. Flexion completely relieved the compression. In each horse, subtotal laminectomy of the caudal two thirds of the dorsal arch of the atlas was used to relieve the spinal cord compression. Two horses recovered fully, one had residual grade-1 neurologic deficits, and a fourth was euthanatized after it fractured a limb 6 weeks after surgery.

Animals↗
PubMed1999

[Anterior screw fixation combined with posterior interlaminar fusion for fracture of axis: report of two cases].

Two cases of axis fracture are reported. Traffic accidents were the cause of injury in both cases. The odontoid process was dislocated anterolaterally with fracture of the lateral mass of the axis in both cases. In Case 1 good alignment of the atlas and axis could not be maintained even with a Halo-vest. The case 2 patient with spinal cord compression caused by dislocation of the axis was referred to our hospital 8 weeks after the accident. Both cases were surgically treated in a similar fashion. Because of the lateral mass fracture and lateral displacement of the atlas relative to the axis, posterior screw fixation with interlaminar fixation (Magerl) was thought to carry a risk of causing damage to the vertebral artery. Because of this, anterior screw fixation combined with posterior wiring was conducted. First, the odontoid process was fixed anteriorly by a screw because it was able to be placed back in good alignment while the patient was in the supine position. Then, the posterior C1-2 interlaminar wiring with iliac bone graft was added. Rigid fixation was obtained without any complication. Various kinds of fixation, such as posterior interlaminar wiring, odontoid screw fixation and Magerl's fixation, have been reported for the treatment of unstable axis fracture. Among them Magerl's method has been regarded as the most stable. When it is not applicable, combination of the first two methods can be an alternative way of treatment for this odontoid process fracture.

Accidents, Traffic↗
PubMed1994

Magnetic resonance imaging of C2 segmental type of vertebral artery.

Two cases with C2 segmental type of vertebral artery (VA) were reported. One case was a 64-year-old man, who was referred to our hospital suffering from vertigo, ataxia, and right facial palsy. Computed tomography (CT) scan showed multiple lacunae in the basal ganglia bilaterally. Another case was a 47-year-old man, complaining of left hemiparesthesia. A small high density area with a little enhancement was seen in the right parietal region in CT scan, and the lesion was diagnosed as cavernous angioma. Angiography of both cases depicted the vertebral artery not passing through the transverse foramen of the Atlas, but running medioposterior to it, and magnetic resonance imaging (MRI) and CT findings showed the vertebral artery running between the Atlas and Axis, and entering into the spinal canal. In our experience of 1669 sides in 1436 cases, such anomaly of the vertebral artery was found in ten cases including the two abovementioned. Six cases of such anomaly have previously been reported, but demonstration of the VA coursing between Atlas and Axis by MRI has not been published in the literature. During surgical therapy on the upper cervical spine, especially when using a posterior approach, or C1-C2 lateral puncture, the possibility of an anomalous vertebral artery, as in our cases, should be taken into consideration.

Cervical Vertebrae↗
PubMed1996

Occipitoatlantal and occipitoaxial hypermobility in Down syndrome.

STUDY DESIGN: In this study, the authors evaluated upper cervical spine in 75 children and adolescents with Down syndrome on the basis of lateral flexion-extension radiographs. OBJECTIVE: To assess occipitoatlantal motion and occipitoaxial motion in children and adolescents with Down syndrome compared with age-matched control subjects. SUMMARY OF BACKGROUND DATA: Although previous studies have described a high prevalence of occipitoatlantal hypermobility in Down syndrome, there have been no comparisons with age-matched control subjects. Only a few reports have mentioned the physiologic relation between the occiput and axis other than basilar impression. Moreover, there have been no reports examining anteroposterior mobility in abnormal conditions. METHODS: Seventy-five children and adolescents with Down syndrome and 30 age-matched control subjects were examined. Lateral radiographs of the upper cervical spine in flexion and extension were taken, and anteroposterior translation of the occiput in relation to the atlas and axis was measured. RESULTS: Anteroposterior occipitoatlantal hypermobility was found to be present in children and adolescents with Down syndrome even when compared with age-matched control subjects. Occipitoaxial hypermobility was observed only when atlantoaxial instability was present. CONCLUSION: In evaluating the upper cervical spine in Down syndrome, it is necessary to pay attention to the relation between the occiput, atlas, and axis.

Adolescent↗
PubMed1978

Congenital occipitoatlantoaxial malformations in the horse.

From a clinical, radiological and morphological study of 9 horses with congenital malformations of the occiput, atlas and axis, and from a study of 2 reported cases, 3 diseases were defined: A. Familial occipitalisation of the atlas with atlantalisation of the axis in Arabian horses (7 cases in this report and the case reported by Leipold, et al., 1974). These horses had congenital atlantooccipital fusion, hypoplasia of the atlas and dens, malformation of the axis and modification of the atlantoaxial joint. B. Congenital asymmetrical occipitoatlantoaxial malformation (2 cases in this report). A Standardbred and a Morgan horse had atlantooccipital fusion, a wedge shaped vertebral piece attached to the caudal end of the axis and sigmoid scoliosis of the cervical vertebrae. C. Asymmetrical atlantooccipital fusion (the case reported by Schmaltz, 1915). This horse of an unknown breed had asymmetrical fusion between the atlas and occiput and cervical scoliosis. The clinical syndromes shown by horses with these malformations were variable but were broadly classified as: 1. Foal dead at birth, seen in one foal with A. 2. Tetraparesis at birth, seen in 5 foals with A. These foals were born with signs varying from tetraparesis to tetraplegia. 3. Progressive ataxia, seen in 2 foals with A. Clinical signs were due to a progressive focal cervical compressive myelopathy. 4. Congenital cervical scoliosis/deviated head, seen in the 2 horses with B and the horse with C. These horses had no signs of spinal cord or brain disease. The diagnoses were made clinically by palpation of the occipitoatlantoaxial region and were confirmed radiographically and/or by post mortem examination in all except one case. Pedigree analysis showed the familial nature of the particular occipitoatlantoaxial malformation seen in horses of only the Arabian breed.

Animals↗
PubMed2001

Selective paralysis of the upper extremities after odontoid fracture: acute central cord syndrome or cruciate paralysis?

A patient presented with selective paralysis of the arms after having sustained a fall. X-ray of the cervical spine showed a type II odontoid fracture with posterior atlantoaxial dislocation. The diagnosis in the emergency room was cruciate paralysis, which is frequently associated with fractures of axis and/or atlas. However, magnetic resonance imaging (MRI) of the cervical spine revealed a lesion consistent with the acute central cord syndrome (CCS) at the C2-C6 level. The patient underwent posterior atlantoaxial arthrodesis to correct instability and was discharged, without much neurological improvement. Cruciate paralysis has been reported to be associated with fractures of axis and/or atlas, and acute CCS has rarely been associated with the fractures. However, this case illustrates that the lesion responsible for selective paralysis of the upper extremities is not as specific as it had been thought to be, and that it is difficult to accurately identify the level of the cervical cord injury by neurological diagnosis and X-rays alone. Supplementary diagnostic modalities, particularly MRI, are required to make a correct diagnosis and develop a therapeutic strategy.

Acute Disease↗
PubMed2005

Extreme tadpoles: the morphology of the fossorial megophryid larva, Leptobrachella mjobergi.

The bizarre larvae of Leptobrachella mjobergi are fossorial and live in the gravel beds of small streams. These tadpoles are vermiform in body shape. Here we present details on their skeleton and musculature, particularly of the head. The entire cranium and its associated musculature are reconstructed in three dimensions from serial histological sections. The hyobranchial apparatus is highly reduced. The head of the L. mjobergi larva is more mobile than in other anuran species. This mobility can largely be ascribed to the exclusion of the notochord from the cranial base and an articulation of the foramen magnum floor with the atlas of the tadpole. The articulation is unique among anuran species, but design parallels can be drawn to salamanders and the articulation between atlas and axis in mammals. In L. mjobergi, the atlas forms an anterior dens that articulates with the basal plate in an accessory, third occipital articular face. The muscle arrangements deviate from the patterns found in other tadpoles: For instance, epaxial and ventral trunk muscles reach far forward onto the skull. The post-cranial skeleton of L. mjobergi is considerably longer than that of other anurans: it comprises a total of 35 vertebrae, including more than 20 post-sacral perichordal centra. Despite a number of features in cranial and axial morphology of L. mjobergi, which appear to be adaptations to its fossorial mode of life, the species clearly shares other features with its megophryid and pelobatid relatives.

Animals↗
PubMed2005

Techniques in the treatment of craniovertebral instability.

The techniques of craniovertebral region stabilization introduced and used by the senior author over the last 20 years are summarized. The lateral masses of atlas and axis are strong and largely cancellous in nature and can be used for direct implantation of screws. Opening up of the joint and placement of bone graft within the joint stabilizes the region and provides a large area for bone fusion. Distraction of the facets provides an opportunity to treat a range of congenital craniovertebral anomalies. The technique of exposure of the lateral mass of the atlas and axis and the atlantoaxial joint is technically relatively complex and needs precise understanding of anatomy of the vertebral artery and training with cadavers.

Adult↗