Short communication: Traits unique to genus Homo within primates at the cervical spine (C2-C7)

The content of the transverse foramen of the seventh cervical vertebra

In human anatomy, the vertebral artery, in its passage from the subclavian artery to the foramen magnum of the skull, enters the transverse foramina of the vertebral column generally at the level of the 6th cervical vertebra. Nevertheless, even though avoided by the vertebral artery, also the 7th cervical vertebra (C7) contains a transverse foramen. The content of this transverse foramen in C7 has been unclear, with different descriptions found in textbooks and in original literature. Here, we have revisited the content of the transverse foramen in C7 by macroscopic dissection of 32 human specimens. We found that the 7th transverse foramen never contained the vertebral artery. Instead, it enclosed in 35 % of the cases both vertebral vein and vertebral nerve, in 20 % of the cases only the vertebral nerve, in 11 % of the cases only the vertebral vein, and in 34 % of the cases it contained no macroscopically visible neurovascular structure at all but only adipose connective tissue.

Double Transverse Foramina-An Anatomical Basis for Possible Vertebrobasilar Insufficiency Risk and Vertebral Artery Injury

Cervical vertebrae may exhibit the anomalous presence of a double transverse foramen (DTF) that may impact the anatomy of related structures that traverse the cervical region, such as the vertebral artery (VA). This retrospective anatomical study utilized CT angiography cervical scans to examine the prevalence of DTF, VA, and TF areas. The subjects were separated into two groups: normal TF (NTF group; 26 males and 21 females) and double TF (DTF group; 21 males and 24 females). The males presented significantly higher TF area values (30.31 ± 4.52 mm2) than the females (27.48 ± 1.69 mm2) in the NTF group (p = 0.006). The sex differences disappeared when a DTF was present (p = 0.662). There were no differences in the VA area values between the sexes in both the NTF and DTF groups (p = 0.184). No significant differences in the VA area values between males of the NTF and DTF groups (p = 0.485) were noted. The DTF subjects presented an increased VA/TF area ratio than the NTF subjects (p < 0.001). This study showed that DTF presence reduced the TF area. In contrast, the VA area did not change despite the decreasing TF area. This might be an anatomical risk for transient vertebrobasilar insufficiency in subjects with DTF, especially in females, because VA space in the TF is less in DTF subjects than in NTF subjects. This may lead to easy VA compression in DTF subjects following neck trauma.

Ontogeny of morphological variations in the vertebral column: Prevalence and bony variability in young Spanish children

Pre- and postnatal development and variability in discrete vertebral traits have been poorly described in embryonic studies. Numerous authors have reported that these variations are observable only from adolescence; scientific publications on the vertebrae of fetuses and infants are scarce. Thus, the aims of this study were to (1) describe the ontogeny and variability of anatomical variations in the vertebral column of a Spanish infant population and (2) analyze the frequency and relationship between sex, age, and intertrait variables. A total of 4728 vertebrae from 197 skeletons were studied. The age at death ranged from 22 intrauterine weeks to 8 years. Twenty morphological traits related to vertebral column development were analyzed. A descriptive statistical analysis was performed, and the chi-square test was used to measure the relationship between sex, age, and intertrait variables. We observed that 88.32% of skeletons expressed discrete traits along the spine. In fetuses, the double transverse foramen and unclosed transverse process of the axis were the most prevalent traits. In infants older than one year, the appearance of the L5 cleft neural arch, unclosed transverse process of the atlas, and craniocaudal shifts were frequent. A significant result was found between sex and the unclosed transverse process in the axis. The intertrait relationship was significant for all traits that shared the same embryonic structure. Morphological variations became visible following the appearance of ossification centers during the pre- and postnatal periods, and their etiology was associated with embryonic development.

An imaging measurement study of normal knee parameters in southeast China

BACKGROUND

Imaging measurement of distal femur and proximal tibia has been the hot point in the research of total knee arthroplasty and prosthesis development, which is an important treatment for patients with advanced knee joint disease. This study retrospectively investigated the digital imaging measurement of normal knee parameters in southeast China and evaluated their clinical value.

METHODS

From February 2010 to May 2014, and in accordance with the inclusion criteria, a total of 677 knees (334 female knees and 343 male knees) were categorized into 3 age groups. Clinical and digital imaging data, including the distal femoral condyle diameter (FCD), tibial plateau diameter (TPD), the distance between the medial tibial plateau and fibular head (DPF), tibiofemoral valgus angle, distal femoral valgus angle, proximal tibia (PT) varus angle and the angle from femoral condyle to tibial perpendicular (FT), were measured by using AutoCAD 10.0 software. All measured variables were statistically analyzed by SPSS statistical software (version 18.0).

RESULTS

Data are presented as the mean ± standard deviation. The normal female and male femoral condyle diameter was (7.69 ± 0.46) cm and (8.68 ± 0.55) cm, while the normal female and male tibial plateau diameter was (7.66 ± 0.46) cm and (8.60 ± 0.55) cm, respectively. The normal female and male DPF was (0.76 ± 0.36) cm and (0.79 ± 0.36) cm. For females and males, the tibiofemoral valgus angle and distal femoral valgus angle were (3.89 ± 2.20) ° and (3.29 ± 2.12) °, (9.03 ± 2.18) ° and (8.25 ± 2.20) °. As the two methods to measure tibial plateau varus angle, PT angle of normal female and male was (4.29 ± 1.86) ° and (4.84 ± 2.23) °, while the normal female and male FT angle was (5.34 ± 1.95) ° and (5.52 ± 2.07) °. Based on the data obtained, we found significant differences between the two genders in terms of the femoral condyle diameter and tibial plateau diameter in all age groups (P < 0.01). The DPF parameter showed an obvious difference between the young group and the middle-aged group (P < 0.05), and no significant difference was observed between the sides and genders (P > 0.05). The distal femoral valgus angle showed statistical differences between genders in the left side of the young group and middle-aged group (P < 0.05), while angle PT and FT showed no significant difference (P > 0.05).

CONCLUSION

A large number of knee measurements was obtained, and a local knee database was developed in this study. Imaging measurement prior to total knee arthroplasty is clinically important for increasing the accuracy and long-term efficacy of total knee arthroplasty. These data can also provide useful information for knee surgery and sports medicine as well as prosthesis development.

A data process of human knee joint kinematics obtained by motion-capture measurement

BACKGROUND

The motion capture has been used as the usual method for measuring movement parameters of human, and most of the measuring data are obtained by partial manual process based on commercial software. An automatic kinematics data process was developed by programming on MATLAB software in this paper.

METHODS

The motion capture measurement of healthy volunteers was carried out and the MATLAB program was used for data process. Firstly, the coordinate data of markers and anatomical points on human lower limb measured by motion capture system were read and repaired through the usual and the patch program. Meantime, the local coordinate systems of human femur and tibia were established with anatomical points. Then flexion/extension, abduction/adduction and internal/external rotation of human knee tibiofemoral joint were obtained by special coordinate transformation program.

RESULTS

Using the above methods, motion capture measurements and batch data processing were carried out on squatting and climbing stairs of 29 healthy volunteers. And the motion characteristics (flexion/extension, internal/external rotation and adduction/abduction) of the knee joint were obtained. For example, the maximum internal/external rotation in squatting and climbing stairs were respectively was 30.5 degrees and 14 degrees, etc. Meantime, the results of this paper also were respectively compared with the results processed by other research methods, and the results were basically consistent, thus the reliability of our research method was verified. After calibration processing, the compiled MATLAB program of this paper can directly be used for efficient batch processing and avoiding manual modeling one by one.

CONCLUSION

A novel Patch Program of this paper has been developed, which can make reasonable compensation for missing and noise signals to obtain more complete motion data. At the same time, a universal data processing program has also been developed for obtaining the relative movement of various components of the human body, and the program can be modified for detail special analysis. These motion capture technologies can be used to judge whether the human body functions are abnormal, provide a reference for rehabilitation treatment and design of rehabilitation equipment, and evaluate the effectiveness before and after surgery.

Possible Clinical Implications of Geographic Differences in Prevalence of Double Transverse Foramen

BACKGROUND

The double transverse foramen (DBLTF) is a cervical spine anatomic variant. Current literature has presented prevalence values of DBLTF in Caucasian Mediterranean subjects that seem to be higher than those observed in other samples of subjects. Therefore we aimed to test if Caucasian Mediterranean subjects present a higher prevalence of the DBLTF than sub-Saharan African subjects.

METHODS

We analyzed the presence of DBLTF in cervical spines of 100 skeletons from Caucasian Mediterranean subjects and 91 skeletons from sub-Saharan African subjects, resulting in a total of 1337 cervical vertebrae having been studied.

RESULTS

No DBLTF was found in vertebrae C1, C2, and C3. The pattern of prevalence observed in all samples analyzed indicated the prevalence ranged from exhibiting the most to the least prevalence as C6 > C5 > C7 > C4. The sub-Saharan African subjects presented a significant reduced DBLTF prevalence of 2.2%, 14.3%, 19.8%, and 3.3% in C4 (P = 0.043), C5 (P = 0.004), C6 (P < 0.001), and C7 (P = 0.041), respectively, than that presented by Caucasian Mediterranean subjects (9.0%, 32.0%, 45.0%, 11.0% in C4, C5, C6, and C7, respectively).

CONCLUSIONS

Our study has revealed that this anatomic variation is more frequently found in Caucasian Mediterranean subjects than in sub-Saharan African subjects.

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.

Discrete morphological variants of human cervical vertebrae: Exploring pattern of distribution and biological significance

Studies on discrete traits of the human cervical vertebrae, appearing at certain intervals during the last century, posed some questions regarding evolutionary processes that human cervical spine underwent during phylogenesis. To address questions of significance of these morphological traits we need first a good knowledge of the extent of their variation in modern humans. The aim of the current work was to integrate available data on the occurrence of various non-metric traits in the human cervical spine and search for the pattern of their distribution on intra- and inter-population levels. The study was based on data from five osteological samples from North America (Terry and Grant collections) and Russia (mid 20th c. and 18th c.); and data taken from literature. Traits were categorized into rare (<3%), low frequency (up to 10%), often encountered (10-30%) and characteristic for modern humans (>50% on average). Several traits showed mild to strong association with each other indicating interrelation between various spine characteristics. Of the traits analyzed, the following had consistent pattern of sex-related variability: complete dorsal ponticle, bifid spinous processes and cervical ribs; and ancestry-related variability: dorsal ponticle and bifid spinous processes. Each ancestry group (European, African, Asian and North American) had its specifics regarding the latter two traits which might be related to genetic isolation. Most of the traits, however, showed relatively similar pattern of distribution among various populations, including the pattern of within-spine variability. This suggests a common intraspecific pattern and a possible link to some fundamental characteristics of the human vertebral column.