| Due to environmental degradation,human intervention and poaching,the wild population of Saiga antelope(Saiga tatarica)in China has been extinct since the1960 s.The existing Saiga antelope population has been developed since 1988 with 11 individuals introduced from the United States and Germany to Gansu Endangered Animal Protection Center of State Forestry Administration of China.After years of careful breeding and management,the way of semi-free range breeding has achieved great success.Due to its early extinction in the wild,small population,high vigilance and difficulty to access,many researches of the Saiga antelope are still in the blank stage.As the first-class protected wild animal in China,Saiga antelope has important conservation value and research significance.To a more comprehensive understanding of the biological characteristics,improve the antelope head disease diagnosis accuracy and the effectiveness of the treatment,to further improve the level of antelope breeding and management,In this study,the Saiga antelope of the Gansu Endangered Animal Protection Center of the State Forestry Administration was used as the research object,using gross anatomy,imaging anatomy and medical image three-dimensional reconstruction technology to conduct a more systematic study of the Saiga skull,which will provide some references for release into the wild,restoration of wild populations and species protection.The results showed as following.1.The gross anatomy of the skull showd that the whole skull of Saiga antelope is a narrow and long tetrahedral cone,and the ratio of skull length to width is about 2:1.The skull consists of two parts,neurocranium and viscerocranium.The neurocranium forms the bony base of the skull cavity.The viscerocranium constitutes the nasal cavity,oral cavity,facial bone foundation.The maxilla of the Saiga is well developed,forming most of the basal and lateral walls of the nasal cavity.The incisor bone is connected with the front part of the maxilla,without nasal process,the snout is long and flat,the nasal space is large,and the nasal bone is degenerated.The frontal bone is well developed,forming the dorsal wall of the skull cavity,nearly pentagonal,the orbital part is convex,the area of the eye socket is large and deep,the frontal scale extends forward and is free,covering the turbinate bone,forming the bony wall of the nasal cavity.Both male and female Saiga antelope have obvious Processus cornuales in the frontal bones,but only male antelope has horns.The undersurface was bubbly,and the body of the occipital bone and the body of the bottom sphenoid bone were completely healed in the adult age.The healing of the suture between other bones was not obvious.2.Cone beam CT was used to scan the subadult head specimens and skull specimens of Saiga antelope,and the cross-section,sagittal and coronal plane sequence tomography images of the head of Saiga antelope were successfully obtained.The anatomical structure of the skull was labeled,and the CT image anatomical atlas of the head of Saiga antelopes was established.Comparing with other ruminant animals,CT imaging showed that the nose of Saiga antelope was significantly enlarged,the nasal cavity was wider,and the nasal vestibular cavity was significantly enlarged.There is a tubular caecal sac structure at the lateral end of the nasal vestibule,opening in the nasal vestibule.The orbit is communicated with the nasal cavity through the nasolacrimal duct,which is opened in the dorsal ventral side of the lacrimal bone.Three kinds of mucosal folds located in the inherent nasal cavity are clearly visible.The upper,middle and lower turbinate bones exist in pairs,which are relatively developed and curled lamina,located in the front of the ethmoid labyrinth and just below the front of the frontal bone.The paranasal sinuses are connected with the nasal cavity and exist in pairs.There are four pairs of paranasal sinuses in adults,frontal sinuses,lacrimal sinuses,maxillary sinuses and sphenoid sinuses.There is a marked difference in the size of the paranasal sinuses.The particularity of the above structures may be related to the characteristics of the habitats they live in,which can better adapt to the desert and semi-desertification environment.3.Mimics 20.0 software was used for 3D reconstruction of DICOM 3.0 format image obtained after cone beam CT scanning,and the high-precision 3D digital model of the skull and brain of Saiga antelope was successfully obtained.The reconstructed digital skull model can realize scaling and rotation,multi-angle cutting and measurement,and can better reflect the external characteristics,internal and three-dimensional structure of the head structure.The 26 morphological parameters of the skull model were measured digitally with the measuring tool of the software,and the results showed there are not significant difference from those of the vernier caliper.Brain volume and brain surface area of two to three months old,five to seven months old and two to four years old were measured and statistics.The results of the brain volume and brain surface area of Saiga antelope in different age groups by ANOVA showed that there were significant differences.In conclusion,this study conducted a detailed gross anatomy and digital anatomy study of the Saiga skull,illustrates the morphological structure of the skull,initially established an antelope image anatomy atlas of the head,the digital 3D model of the skull,antelope head for disease diagnosis and treatment,and to provide some references in species protection.This study will provide some theoretical references for the clinical application and related research of CT scan and medical image three-dimensional visualization technology in wild animals. |
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