scholarly journals Thoracic vertebral count and thoracolumbar transition in Australopithecus afarensis

2017 ◽  
Vol 114 (23) ◽  
pp. 6000-6004 ◽  
Author(s):  
Carol V. Ward ◽  
Thierra K. Nalley ◽  
Fred Spoor ◽  
Paul Tafforeau ◽  
Zeresenay Alemseged

The evolution of the human pattern of axial segmentation has been the focus of considerable discussion in paleoanthropology. Although several complete lumbar vertebral columns are known for early hominins, to date, no complete cervical or thoracic series has been recovered. Several partial skeletons have revealed that the thoracolumbar transition in early hominins differed from that of most extant apes and humans. Australopithecus africanus, Australopithecus sediba, and Homo erectus all had zygapophyseal facets that shift from thoracic-like to lumbar-like at the penultimate rib-bearing level, rather than the ultimate rib-bearing level, as in most humans and extant African apes. What has not been clear is whether Australopithecus had 12 thoracic vertebrae as in most humans, or 13 as in most African apes, and where the position of the thoracolumbar transitional element was. The discovery, preparation, and synchrotron scanning of the Australopithecus afarensis partial skeleton DIK-1-1, from Dikika, Ethiopia, provides the only known complete hominin cervical and thoracic vertebral column before 60,000 years ago. DIK-1-1 is the only known Australopithecus skeleton to preserve all seven cervical vertebrae and provides evidence for 12 thoracic vertebrae with a transition in facet morphology at the 11th thoracic level. The location of this transition, one segment cranial to the ultimate rib-bearing vertebra, also occurs in all other early hominins and is higher than in most humans or extant apes. At 3.3 million years ago, the DIK-1-1 skeleton is the earliest example of this distinctive and unusual pattern of axial segmentation.

Author(s):  
Martin E. Atkinson

The surface anatomies of the face and neck and their supporting structures that can be palpated have been described in Chapter 20. It is now time to move to the structures that lie under the skin but which cannot be identified by touch starting with the neck and moving up on to the face and scalp. The cervical vertebral column comprises the seven cervical vertebrae and the intervening intervertebral discs. These have the same basic structure as the thoracic vertebrae described in Section 10.1.1. Examine the features of the cervical vertebra shown in Figure 23.1 and compare it with the thoracic vertebra shown in Figure 10.3. You will see that cervical vertebrae have a small body and a large vertebral foramen. They also have two distinguishing features, a bifid spinous process and a transverse foramen, piercing each transverse process; the vertebral vessels travel through these foramina. The first and second vertebrae are modified. The first vertebra, the atlas, has no body. Instead, it has two lateral masses connected by anterior and posterior arches. The lateral masses have concave superior facets which articulate with the occipital condyles where nodding movements of the head take place at the atlanto-occipital joints. The second cervical vertebra, the axis, has a strong odontoid process (or dens because of its supposed resemblance to a tooth) projecting upwards from its body. This process is, in fact, the body of the first vertebra which has fused with the body of the axis instead of being incorporated into the atlas. The front of the dens articulates with the back of the anterior arch of the atlas; rotary (shaking) movements of the head occur at this joint. The seventh cervical vertebra has a very long spinous process which is easily palpable. The primary curvature of the vertebral column is concave forwards and this persists in the thoracic and pelvic regions. In contrast, the cervical and lumbar parts of the vertebral column are convexly curved anteriorly. These anterior curvatures are secondary curvatures which appear in late fetal life. The cervical curvature becomes accentuated in early childhood as the child begins to support its own head and the lumbar curve develops as the child begins to sit up.


Author(s):  
Martin E. Atkinson

The locomotor system comprises the skeleton, composed principally of bone and cartilage, the joints between them, and the muscles which move bones at joints. The skeleton forms a supporting framework for the body and provides the levers to which the muscles are attached to produce movement of parts of the body in relation to each other or movement of the body as a whole in relation to its environment. The skeleton also plays a crucial role in the protection of internal organs. The skeleton is shown in outline in Figure 2.1A. The skull, vertebral column, and ribs together constitute the axial skeleton. This forms, as its name implies, the axis of the body. The skull houses and protects the brain and the eyes and ears; the anatomy of the skull is absolutely fundamental to the understanding of the structure of the head and is covered in detail in Section 4. The vertebral column surrounds and protects the spinal cord which is enclosed in the spinal canal formed by a large central canal in each vertebra. The vertebral column is formed from 33 individual bones although some of these become fused together. The vertebral column and its component bones are shown from the side in Figure 2.1B. There are seven cervical vertebrae in the neck, twelve thoracic vertebrae in the posterior wall of the thorax, five lumbar vertebrae in the small of the back, five fused sacral vertebrae in the pelvis, and four coccygeal vertebrae—the vestigial remnants of a tail. Intervertebral discs separate individual vertebrae from each other and act as a cushion between the adjacent bones; the discs are absent from the fused sacral vertebrae. The cervical vertebrae are small and very mobile, allowing an extensive range of neck movements and hence changes in head position. The first two cervical vertebrae, the atlas and axis, have unusual shapes and specialized joints that allow nodding and shaking movements of the head on the neck. The thoracic vertebrae are relatively immobile. combination of thoracic vertebral column, ribs, and sternum form the thoracic cage that protects the thoracic organs, the heart, and lungs and is intimately involved in ventilation (breathing).


Author(s):  
P. Sridevi ◽  
K. Rajalakshmi ◽  
M. Sivakumar ◽  
A. Karthikeyan

Background: Indian eagle owl known to rotate their necks up to 270 degrees in either direction without injuring their vessels running below the head thereby without cutting off blood supply to their brains. The vertebral column in birds carry peculiar features like higher number of cervical vertebrae due to long mobile neck, lumbar and sacral vertebrae fused together giving rigidity which aid in flight. The extensive fusion of vertebral column posterior to the neck provides the required rigidity in the trunk region, this inflexibility feature might reduce weight, as it avoids the need for extensive musculature to maintain a streamlined and rigid body posture during flight. The current study aimed to study the vertebral column of Indian eagle owl in order to understand the anatomical adaptations related to this species. Methods: The specimens were procured from three Indian eagle owl brought for post mortem examination during the year 2019 to the Department of Veterinary Pathology, Rajiv Gandhi Institute of Veterinary Education and Research, Puducherry. After completion of the post-mortem examination the carcass was collected and macerated as per the standard technique and various measurements on vertebral column bones were measured using vernier calliper. Result: The study revealed that vertebral column of Indian eagle owl consisted of 14 cervical vertebrae, 7 thoracic vertebrae, 13 to 14 lumbar vertebrae fused with sacral vertebrae forming synsacrum and 7 coccygeal vertebrae. The hypapophyses of the 14th cervical vertebra and first two thoracic vertebrae were trifid in nature specific feature seen in Indian eagle owl. The vertebral column had characteristics features of hypapophyses, transverse process, pneumatic foramen and neural spine which enable the owl to adapt for head rotation and various task involving vertebrae.


2021 ◽  
Vol 39 (2) ◽  
pp. 1-18
Author(s):  
Maripaz Chinchilla-Barboza ◽  
Siam Chiquillo-Vergara ◽  
Valeria Delgado-Álvarez ◽  
Susan Gutiérrez-Gutiérrez ◽  
Johnny Steven Mora-Aleman ◽  
...  

The Choloepus Hoffmani is a mammal belonging to the Xenarthra superorder; xenarthrans are distributed from North to South America. It is common for these animals to require medical attention at wildlife rescue centers after being attacked by domestic animals or run over by cars. A proper understanding of this species’ anatomy is vital in order to be able to offer them a proper level of clinical attention. This publication aims to describe the spine’s anatomical and radiographic characteristics of the Choloepus Hoffmani. Four individuals were used in this research; the spine bones were cleaned by boiling and maceration. In the results, it was possible to observe how the postcranial axial skeleton in the sloths is made up by five of distinctive vertebra types. In the spine were found: six cervical vertebrae, a variable number of thoracic vertebrae, xenarthrous lumbar vertebrae, and a fusion between the sacrum and coxal bone. Finally, four underdeveloped caudal vertebrae were also identified in a small stump-like tail. Radiographically, no pathologies were observed in the alignment or structure of the spine. In conclusion, the present study described both the osteology alongside the anatomical radiography of the vertebral column of the Choloepus hoffmani, highlighting the particularities that are not found in domestic mammals and other members of the Xenarthra superorder. Information of this kind is relevant for forensic wildlife analysis, alongside aiding the treatment of animals in this species who suffered lesions in their spine.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Priscilla Magno ◽  
Mouen A. Khashab ◽  
Manuel Mas ◽  
Samuel A. Giday ◽  
Jonathan M. Buscaglia ◽  
...  

Background. NOTES techniques allow transesophageal access to the mediastinum. The aim of this study was to assess the feasibility of transesophageal biopsy of thoracic vertebrae.Methods. Nonsurvival experiments on four 50-kg porcine animals were performed. Transesophageal access to the mediastinum was attained using submucosal tunneling technique.Results. The posterior mediastinum was successfully accessed and navigated in all animals. Vertebral bodies and intervertebral spaces were easily approached while avoiding damage to adjacent vessels. Bone biopsy was successfully performed without complications, but the hardness of bone tissue resulted in small and fragmented samples.Conclusions. Peroral transesophageal access into the posterior mediastinum and thoracic vertebral bone biopsy was feasible and safe. The proximity of the esophagus to the vertebral column provides close and direct access to the thoracic spine and opens up new ground for the performance of multilevel anterior spine procedures using NOTES techniques.


2016 ◽  
Vol 22 (3) ◽  
pp. 186-191
Author(s):  
S. Malik ◽  
P. Bordei ◽  
A. Rusali ◽  
D. M. Iliescu

Abstract Our study was conducted by consulting angioCT sites made on a CT GE LightSpeed VCT64 Slice CT and a CT GE LightSpeed 16 Slice CT, following the path and relationships of the descending thoracic aorta against the vertebral column, outside diameters thereof at the thoracic vertebrae T4, T7, T12 and posterior intercostal arteries characteristics. The origin of of the descending thoracic aorta we found most commonly on the left flank of the lower edge of the vertebral body T4, but I have encountered cases where it had come above the lower edge of T4 on level of intervertebral disc T4-T5 or even at the upper edge of T5 vertebral body. At thoracic vertebra T4, on a total of 30 cases, the descending thoracic aorta present a diameter of 20.0 to 32.6 mm, values that correspond to male gender and to females diameter ranging from 25.5 to 27, 4 mm. At level of T7 thoracic vertebra, thoracic aorta present a diameter of 19.6 to 29.5 mm, values found in men, in women the diameter being from 21.9 to 25.2 mm. At thoracic vertebra T12, on a total of 27 cases, the descending thoracic aorta present a diameter of 17.6 to 27.7 mm, in males the diameter was from 17.6 to 27.7 mm and females diameter ranging from 21.1 to 25.2. The length of the descending thoracic aorta was from 18.40 to 19.41 cm.


2016 ◽  
Vol 3 (2) ◽  
pp. 150604 ◽  
Author(s):  
Megu Gunji ◽  
Hideki Endo

Here we examined the kinematic function of the morpho- logically unique first thoracic vertebra in giraffes. The first thoracic vertebra of the giraffe displayed similar shape to the seventh cervical vertebra in general ruminants. The flexion experiment using giraffe carcasses demonstrated that the first thoracic vertebra exhibited a higher dorsoventral mobility than other thoracic vertebrae. Despite the presence of costovertebral joints, restriction in the intervertebral movement imposed by ribs is minimized around the first thoracic vertebra by subtle changes of the articular system between the vertebra and ribs. The attachment area of musculus longus colli , mainly responsible for ventral flexion of the neck, is partly shifted posteriorly in the giraffe so that the force generated by muscles is exerted on the cervical vertebrae and on the first thoracic vertebra. These anatomical modifications allow the first thoracic vertebra to adopt the kinematic function of a cervical vertebra in giraffes. The novel movable articulation in the thorax functions as a fulcrum of neck movement and results in a large displacement of reachable space in the cranial end of the neck. The unique first thoracic vertebra in giraffes provides higher flexibility to the neck and may provide advantages for high browsing and/or male competition behaviours specific to giraffes.


Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 333-346 ◽  
Author(s):  
A.C. Burke ◽  
C.E. Nelson ◽  
B.A. Morgan ◽  
C. Tabin

A common form of evolutionary variation between vertebrate taxa is the different numbers of segments that contribute to various regions of the anterior-posterior axis; cervical vertebrae, thoracic vertebrae, etc. The term ‘transposition’ is used to describe this phenomenon. Genetic experiments with homeotic genes in mice have demonstrated that Hox genes are in part responsible for the specification of segmental identity along the anterior-posterior axis, and it has been proposed that an axial Hox code determines the morphology of individual vertebrae (Kessel, M. and Gruss, P. (1990) Science 249, 347–379). This paper presents a comparative study of the developmental patterns of homeobox gene expression and developmental morphology between animals that have homologous regulatory genes but different morphologies. The axial expression boundaries of 23 Hox genes were examined in the paraxial mesoderm of chick, and 16 in mouse embryos by in situ hybridization and immunolocalization techniques. Hox gene anterior expression boundaries were found to be transposed in concert with morphological boundaries. This data contributes a mechanistic level to the assumed homology of these regions in vertebrates. The recognition of mechanistic homology supports the historical homology of basic patterning mechanisms between all organisms that share these genes.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Anjali M Prabhat ◽  
Catherine K Miller ◽  
Thomas Cody Prang ◽  
Jeffrey Spear ◽  
Scott A Williams ◽  
...  

The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.


2013 ◽  
Vol 1 (1) ◽  
pp. 61-65
Author(s):  
Michael G. Dudin ◽  
Dmitry Yu. Pinchuk

In the paper we discussed and analyzed the issues that confront practicing orthopedists with the most mysterious and at the same time the most studied vertebral column lesion in children and adolescents - idiopathic scoliosis. Nowadays a great amount of information on its various aspects has been already accumulated, but a practical output in the form of a system of effective treatment has not been yet found and (we can’t even speak about) there is no speech at all about the prevention (prophylactic) of the disease (scoliosis). On the basis of the own many year’s experience with this category of patients and the results of a comprehensive multi-faceted survey, the authors acquired the right to form their own point of view on the etiology and pathogenesis of the three-plane deformation in orthograde human (homo erectus). In this paper, the authors present their reflections on the history of the study of scoliosis, the terminology, statistical indicators and the existing views on its origins. Concerning argumentation on the own findings (conclusions) and views on the disease the authors plan to tell in the following sections.


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