Krapina atlases suggest a high prevalence of anatomical variations in the first cervical vertebra of Neanderthals.

The first cervical vertebra, atlas, and its anatomical variants have been widely studied in Homo sapiens. However, in Neanderthals, the presence of anatomical variants of the atlas has been very little studied until very recently. Only the Neanderthal group from the El Sidrón site (Spain) has been analysed with regard to the anatomical variants of the atlas. A high prevalence of anatomical variants has been described in this sample, which points to low genetic diversity in this Neanderthal group. Even so, the high prevalence of anatomical variations detected in El Sidrón Neanderthal atlases needs to be confirmed by analysing more Neanderthal remains. In this context, we analysed the possible presence of anatomical variants in the three Neanderthal atlases recovered from the Krapina site (Croatia) within the Neanderthal lineage. Two of the three Krapina atlases presented anatomical variations. One atlas (Krapina 98) had an unclosed transverse foramen and the other (Krapina 99) presented a non-fused anterior atlas arch. Moreover, an extended review of the bibliography also showed these anatomical variations in other Middle and Upper Pleistocene hominins, leading us to hypothesise that anatomical variations of the atlas had a higher prevalence in extinct hominins than in modern humans.

Can the transverse foramen/vertebral artery ratio of double transverse foramen subjects be a risk for vertebrobasilar transient ischemic attacks?

The C6 is the cervical vertebra into which the vertebral artery enters the passage of the transverse foramen and it is the vertebra most affected by double transverse foramina. There is currently little information about the relation between the vertebral artery and the double transverse foramen in C6. We aimed to test whether subjects with a double transverse foramen in C6 have a reduced transverse foramen/vertebral artery ratio when compared with normal anatomy subjects who possess a single transverse foramen which may be a risk for transient vertebral artery stenosis. We measured the area of the transverse foramen and the vertebral artery in 27 double transverse and 56 normal anatomy subjects using computed tomography angiography. We found significant differences in the area of the transverse foramen between double transverse and normal subjects (P < 0.001) but not between the vertebral artery area of double transverse and normal subjects (P = 0.829). The subjects with double transverse foramina have a reduced transverse foramen/vertebral artery ratio, which may be a possible risk for transient vertebral artery stenosis.

Retrotransverse foramen of the atlas: prevalence and bony variations.

PURPOSE: To analyze the prevalence of the retrotransverse foramen (RTF) and its bony variations. METHODS: One hundred ten atlases of living adult subjects, 161 twentieth century dry adult cervical atlases and four dry adult cervical atlases from medieval skeletons were studied to detect the RTF and its abnormal bony variations. The 110 living adult subjects underwent a computed tomography study to detect the RTF. RESULTS: In the in vivo sample (n = 110; 100%), the RTF was found in four (3.6%) atlases. It was bilateral in all cases, but three (2.7%) patients showed complete RTF and the other patient presented a complete RTF in the left transverse process and an unclosed RTF in the right transverse process. In addition, the RTF was observed in combination with an unclosed transverse foramen in two cases (1.8%). In the twentieth century skeletal sample (n = 206; 100%) the RTF was found in 15 (7.3%) C1 vertebrae. It was bilateral in three (1.5%) vertebrae and unilateral in another 12 (5.8%) vertebrae. In the medieval skeletal sample (n = 4; 100%) one cadaveric atlas (25%) presented a bilateral RTF with special bony characteristics which presented an unexpected spicula in the left RTF. CONCLUSIONS: The RTF is a nonmetric variant of the atlas vertebra that can present non-degenerative and non-traumatic spiculae or it can be unclosed. In addition, it can be associated with the presence of unclosed transverse foramina.

Acute headache attributed to whiplash in arcuate foramen and non-arcuate foramen subjects.

PURPOSE: To test the association between arcuate foramen (AF) in the first cervical vertebra with acute headache attributed to whiplash. METHODS: Retrospective study of 128 patients that suffered a whiplash. The presence or absence of AF was recorded after a radiographic study, as well as the presence or absence of acute headache after the whiplash. RESULTS: The frequency of AF was 17.2%. Patients with bilateral AF presented a significant (p = 0.000, Fisher's test) increase in the frequency of acute headache (90.9%) in comparison with the non-AF group (5.7%). The ratio between the presence and absence of acute headache was 166.6 times higher (IC 95% 18.2-1526.22) in subjects with bilateral AF in comparison with non-AF subjects. CONCLUSIONS: The presence of bilateral AF is associated to an increased frequency of acute headache after suffering a whiplash, information of interest for the attention to these patients.

Analysis of the relationship between the double transverse foramen and the possibility of developing clinical symptoms after whiplash.

Currently, there is no information about the possibility of developing clinical symptoms after whiplash in double transverse foramen subjects. Our aim was to test whether subjects with double transverse foramen have an increased risk of presenting with an acute headache, dizziness, vertebral artery dissection, and vomiting after whiplash.We recorded the absence/presence of double transverse foramen, and the absence/presence of neck pain, acute headache, dizziness, vertebral artery dissection, and vomiting in 85 patients who had suffered whiplash injuries in car rear-end impacts in road traffic accidents. We used the odds ratio test to determine whether double transverse foramen subjects are at a higher risk of developing an acute headache, dizziness, and vomiting than non-double transverse foramen subjects.Although double transverse foramen subjects presented with more clinical symptoms after whiplash, the odds ratio test revealed that their risks of developing acute headache (P = 0.30), dizziness (P = 0.09), or vomiting (P = 0.18) were not significantly greater than in the control group.Double transverse foramen subjects are not at a higher risk of presenting acute headache, dizziness, vertebral artery dissection, and vomiting after whiplash. Clin. Anat. 30:761-766, 2017. © 2017Wiley Periodicals, Inc.

Association between ribs shape and pulmonary function in patients with Osteogenesis Imperfecta.

The aim of the present study was to test the hypothesis that ribs shape changes in patients with OI are more relevant for respiratory function than thoracic spine shape. We used 3D geometric morphometrics to quantify rib cage morphology in OI patients and controls, and to investigate its relationship with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), expressed as absolute value and as percentage of predicted value (% pred). Regression analyses on the full sample showed a significant relation between rib shape and FEV1, FVC and FVC % pred whereas thoracic spine shape was not related to any parameter. Subsequent regression analyses on OI patients confirmed significant relations between dynamic lung volumes and rib shape changes. Lower FVC and FEV1 values are identified in OI patients that present more horizontally aligned ribs, a greater antero-posterior depth due to extreme transverse curve at rib angles and a strong spine invagination, greater asymmetry, and a vertically short, thoraco-lumbar spine, which is relatively straight in at levels 1-8 and shows a marked kyphosis in the thoraco-lumbar transition. Our research seems to support that ribs shape is more relevant for ventilator mechanics in OI patients than the spine shape.

The Retrotransverse Foramen of the Atlas Is not a Modern Anatomic Variation.

BACKGROUND: The retrotransverse foramen (RTF) is a nonmetric variant of the atlas vertebra that consists of an abnormal accessory foramen located on the posterior root of the transverse process and it extends from the posterior root of the transverse process to the root of the posterior arch. Its presence has been related to regional variations of the venous circulation. It is currently unknown whether the RTF is a modern or an ancient anatomic variation. CASE DESCRIPTION: We analyzed the skeletal remains from the late-ancient Roman necropolis (II-VI centuries ad) of La Boatella (Valencia, Spain) and we found a well-preserved individual skeleton that presented with a left retrotransverse foramen in C1. CONCLUSIONS: The RTF is not a modern anatomic variation. As a result, ancient individuals had the same modifications in the regional circulation as modern subjects present today.

Double Retrotransverse Foramen of Atlas (C1).

BACKGROUND: The retrotransverse foramen is a nonmetric variant of C1 that consists of an abnormal accessory foramen on the posterior root of the transverse process. CASE DESCRIPTION: During a study on the prevalence of the retrotransverse foramen in 150 dry C1 vertebrae, we observed an exceptional C1 (0.67%) with a right double retrotransverse foramen of the 14 C1 vertebrae (9.3%). This has not been reported previously in the literature. No osteogenic reaction and no degenerative signs were observed in this C1 with the double retrotransverse foramen. CONCLUSIONS: Neurosurgeons should be aware of the possible presence of the "conventional" retrotransverse foramen and the "exceptional" double retrotransverse foramen so that they can safely plan to prevent surgical complications. This will thus ensure better patient management by neurosurgeons.

Prevalence of anatomic variations of the atlas vertebra.

BACKGROUND CONTEXT: The retrotransverse foramen (RTF), arcuate foramen (AF), unclosed transverse foramen (UTF) and posterior atlas arch defects (PAAD) are anatomic variations of the atlas vertebra that surgeons must be aware of before spine surgery is performed. PURPOSE: To analyze the prevalence of the AF, RTF, UTF, and PAAD. STUDY DESIGN: Ex-vivo anatomical study. PATIENT SAMPLE: Two hundred eighteen atlas vertebrae obtained from 100 Caucasian subjects and 118 sub-Saharan African subjects (48 Sotho subjects, 35 Xhosa subjects and 35 Zulu subjects). METHODS: We studied 218 atlas vertebrae from skeletons of the Raymond A. Dart Collection in order to analyze the prevalence of AF, RTF, UTF, and PAAD in both Caucasian and sub-Saharan African subjects. OUTCOME MEASURES: Not applicable. RESULTS: Sixty-nine (31.2%) atlases presented anatomical variants: 64 (29.3%) presented one anatomical variant, 4 (1.8%) presented two, and 1 (0.5%) presented three. AF, RTF, UTF, Type A and Type E defects were present in 35 (16.1%), 17 (7.8%), 17 (7.8%), 5 (2.3%), and 1 (0.5%) vertebrae, respectively. The vertebrae with two anatomical variants presented a bilateral UTF and a Type A defect, a bilateral AF and a Type A defect, a right UTF and a left AF, and a right UTF and a Type E defect. The vertebra with three anatomical variants presented a bilateral RTF, a left UTF, and a left AF. No sex differences in prevalence of the RTF (p=.775), AF (p=.605), UTF (p=.408) and Type A defects (p=1.000) were found in the sub-Saharan African and Caucasian groups (RTF, p=.306; AF, p=.346; UTF, p=.121; Type A defects, p=.561). Comparison between the sub-Saharan African (all subjects) and the Caucasian group revealed no differences in the UTF (p=.105), AF (p=.144), RTF (p=.542) and Type A defects (p=.521) prevalence. Also, no differences in the prevalence of the UTF (p=.515), AF (p=.278), and RTF (p=.857) between Zulu, Xhosa and Sotho subjects were found. Neither were found sex differences in the prevalence of UTF, RTF and AF in Zulu (p=.805, p=.234, p=.129), Xhosa (p=.269, p=.181, p=.309), and Sotho subjects (p=.062, p=.590, p=.106). CONCLUSIONS: The present study has revealed no sex differences in the prevalence of AF, UTF, RTF or PAAD in both Caucasian and sub-Saharan African subjects. This research has also indicated no differences in the prevalence of the UTF, AF and RTF between Zulu, Xhosa and Sotho subjects. In addition, this study has revealed no differences in the Type A, UTF, AF, and RTF prevalence between the sub-Saharan African (all subjects) and the Caucasian subjects. These variations may be known by surgeons before spine surgery for better planning.

Unexpected Persistent Dentocentral Synchondrosis of C2.

BACKGROUND: The persistence of synchondrosis in adulthood can confound diagnostic decisions made during patient management. CASE DESCRIPTION: A 59-year-old woman who presented neck pain, acute headache, and acute cervical myelopathy symptoms after suffering whiplash grade 3 in a car rear-end impact underwent a conventional radiologic study that revealed no fracture and no anatomic spine variations. The magnetic resonance imaging study revealed no spinal cord intensity signal changes, but it showed a persistent (remnant) dentocentral synchondrosis that was undetected in a previous conventional radiographic evaluation. CONCLUSIONS: The localization and level of the remnant of the dentocentral synchondrosis are extremely important from the clinical viewpoint because of odontoid and C2 fractures. Neurosurgeons should thus be aware of the possible presence of a persistent (remnant) C2 dentocentral synchondrosis in adult subjects in order to avoid misdiagnosis with C2 fracture.

Atlases with Arcuate Foramen Present Cortical Bone Thickening That May Contribute to Lower Fracture Risk.

BACKGROUND: To date, no information about the cortical bone microstructural properties in atlas vertebrae with arcuate foramen has been reported. As a result, we aimed to test in an experimental model if there is a cortical bone thickening in an atlas vertebra which has an arcuate foramen that may play a protective role against bone fracture. METHODS: We analyzed by means of micro-computed tomography the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry atlas vertebrae with arcuate foramen and without arcuate foramen. We also reviewed a case series of 31 posterior atlas arch fractures to correlate the possible presence in the same atlas of both fracture and arcuate foramen. RESULTS: The micro-computed tomography study revealed significant differences in cortical bone thickness (P < 0.001), cortical volume (P < 0.004), and medullary volume (P = 0.013) values between the arcuate foramen vertebrae and the nonarcuate foramen vertebrae. The clinical series found no coexistence in the same vertebra of a posterior atlas arch fractures and the arcuate foramen. CONCLUSIONS: An atlas with arcuate foramen presents cortical bone thickening. This advantage in bone microarchitecture seems to contribute to a lower fracture risk compared to subjects without arcuate foramen as no coexistence in the same vertebra of a posterior atlas arch fractures and arcuate foramen was found.

The Decreasing Prevalence of the Arcuate Foramen.

BACKGROUND: The arcuate foramen (AF), or ponticulus posticus, is an anatomic variant of the first cervical vertebra that consists of a complete or partial osseous bridge over the groove for the vertebral artery and extends from the posterior aspect of the superior articular facet to the superior lateral border of the posterior arch. The AF has been associated with clinical symptoms, such as headache, migraine, neck pain, shoulder pain, arm pain, and vertebral artery dissection. We aimed to test whether the prevalence of the AF has decreased in the modern human population over the past centuries as a result of reduction in inbreeding and endogamy. METHODS: Possible reduction in the prevalence of the AF was assessed by comparing a 17th century rural sample (n = 108) with a 20th century modern urban sample (n = 192). RESULTS: When comparing the 17th and the 20th century samples, we found a statistically significant (P = 0.003) reduction of 14.5% (95% confidence interval 4.5-24.5) in the prevalence of the AF. CONCLUSIONS: Prevalence of the AF has been decreasing over the past centuries.

Cortical bone thickening in Type A posterior atlas arch defects: experimental report.

BACKGROUND CONTEXT: To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. PURPOSE: To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. STUDY DESIGN: Micro-computed tomography (CT) study on cadaveric atlas vertebrae. METHODS: We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. RESULTS: The micro-CT study revealed significant differences in cortical bone thickness (p=.005), cortical volume (p=.003), and medullary volume (p=.009) values between the normal and the Type A vertebrae. CONCLUSIONS: Type A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures.