Application Of Hard Tissue Section Technique In The Observation Of TMJ Morphology And Tissue Structure In Three Large Animals

[Objective]In this study,the temporomandibular joint(TMJ)of three kinds of large animals were compared using the technique of hard tissue section.Through the process without not decalcified TMJ structure respectively for anatomical observation,image measurement,his red O-solid green stain,toluidine blue staining and collagen fiber dyeing,compare three animals TMJ similarities and differences between morphological structure and organizational structure,perfect the large animals of the temporomandibular joint research materials,for temporomandibular joint disease basic research provides the theory basis for selection model animals.[Methods]The adult healthy beagle,diannan small ear pig and goat cadaver head with normal skull development were collected by anatomical methods.CT was taken for imaging observation,and the condyles on both sides were compared to see whether the condyle morphology was consistent,whether there was congenital bone defect,whether there was joint space in the sagittal position and the width of the anterior,upper and posterior Spaces were measured,and the Angle of the upper and lower bevel planes on the inner and outer sides were measured in the coronal position.The gross anatomy of the temporomandibular joint was observed and compared.The anterior and posterior diameters,the internal and external diameters of the condyle,the length and width of the bony carina on the surface of the condyle,the lengths of the condyle edges,the anterior and posterior diameters of the articular disc,and the internal and external diameters were measured using a vernier caliper.Angle ruler was used to measure the Angle of the bevel plane before and after the condyle,and the connecting line of the lowest point of condyle cartilage was used as the reference plane to measure the Angle of the bevel plane before and after the condyle and the reference plane.Use the thickness gauge to measure the thickness of the edge of the articular disc,the thickness of the central region;Condyle surface area was measured by image pro plus software.The cell composition and arrangement characteristics of the articular disc and condylar cartilage of the temporomandibular joint(TMJ)were observed by staining with fan-o solid green,toluidine blue,collagen fiber and elastic fiber.To observe the presence of articular surface bands,proliferation bands,fibrous cartilage bands,calcified cartilage bands and to compare their similarities and differences.[Resultss]1.CT image measurement of joint space:the front joint space of beagle was 0.88mm,the upper joint space was 0.75mm,and the rear joint space was 0.93mm.In southern yunnan,the anterior joint clearance,the supraarticular clearance and the posterior joint clearance were 1.57mm,0.89mm and 1.20mm respectively.In goat,the anterior joint clearance was 1.65mm,the upper joint clearance was 1.70mm,and the posterior joint clearance was 1.77mm.2.Anatomical and morphological results:the temporomandibular joint(TMJ)of beagle,diannan small ear pig and goat was all composed of the articular fossa and nodules above,the mandibular condyle below,the joint disc in the middle of the two and the joint capsule around the outside,and the overall structure of TMJ was similar.3.Results of structural observation of each part of TMJ in beagle dog:the inner and outer diameter of the condyle of beagle was about 17.04mm,and the anteroanterior diameter was 10.04mm.The fusiform area of the upper condyle was about 103.14mm2.The Angle of the anterior and posterior slopes of the condyle was 135 degrees,and the Angle of the connecting line of the lowest point of the anterior and posterior slopes was 65 degrees.The condyle neck is 2.80mm wide.The length of the inner and outer diameter of the joint disc was 18.04mm,the maximum anteroposterior diameter of the joint disc was 11.74mm,and the height was 9.54mm.The joint disc is approximately oval with an area of 252.74mm2.The central part of the joint disc is round and transparent,with a thickness of about 0.25mm,a front and rear diameter of 7.14mm,an inner and outer diameter of 11.02mm,and a thick annular edge with a thickness of 1.48mm.The fossa was formed into a horseshoe shape to accommodate the joint,which was composed of the zygomatic end and the articular surface of the temporal bone.The width of the fossa was 13.14mm,and the height of the fossa was 2.20mm.,the medial central part is concave and the width of the concave is 4.9mm,the width of the anterior oblique plane of the articular fossa is 5.80mm,and the width of the posterior oblique plane of the articular fossa is 7.34mm.4.Results of structural observation of each part of TMJ in diannan small ear pig:The inner and outer diameter of the condyle of the small ear pig in southern yunnan was 24.42mm,the anterior and posterior diameter of the condyle was 29.10mm,and the shuttle-like area of the upper condyle was about 466.273mm2.The intersection Angle between the anterior condyle and the posterior condyle was 118 degrees,and the intersection Angle between the anterior condyle and the posterior condyle was 53 degrees.The posterior side of the condyle was covered with adipose tissue,with a length of 3.70mm and a maximum width of 11.78mm.The attachment of the medial segment capsule was 11.80mm in length and 2mm in width.The articular disc is a quasi-oval with front width and back narrowness,with the maximum anteroposterior diameter of 24.42mm,the maximum inner and outer diameter and the front inclined plane of the articular disc,the width of the front inclined plane of 15.20mm and the width of the rear inclined plane of 14.70mm.The surface area of the articular disc was 510.675mm2.The anterior oblique plane of the articular fossa is an ellipse with a front and rear diameter of 20.60mm and an inner and outer diameter of 20.20mm.5.Results of structural observation of each part of TMJ in goat:The inner and outer diameter of the condyle of goat was 22.10mm,and the anterior and posterior diameter of the condyle was 11.92mm.The area of the articular surface of the condyle was about 228.983mm2,and the posterior slope of the condyle was located at 1/3 of the posterior medial side of the condyle.The length of the area was 7.10mm,and the width was 3.70mm.The Angle of intersection between the anterior condyle and the posterior condyle is 62 degrees.The Angle of intersection between the anterior condylar slope and the lowest point of the condylar anterior and posterior slopes covering the cartilage was 27 degrees,and no significant condylar neck narrowing was observed.The articular disc is divided into two slanted surfaces:the maximum inner and outer diameters are 22.00mm,the anteroposterior diameters are 10.40mm,the central ridge length is 17.10mm,and the thickness is 1.00mm.The central zona pellucida extends from the anterior slanted surface of the articular disc to the posterior slanted surface of the articular disc,and the total length is about 19.58mm.The joint disc area was about 252.74mm2.The articular fossa can be divided into anterior and posterior slopes,with an internal and external diameter of 23.84mm and an anteroposterior diameter of 18.10mm.The posterior slope of the articular nodule is located at 1/3 of the articular fossa,with an internal and external diameter of 9.12mm and a anteroposterior diameter of 4.82mm.6.Tissue structure:the articular disc contains a large number of collagen fibers,interwoven into a network.The condylar surfaces of the three animals were covered with cartilage,and the cartilage layers were obvious,which could be divided into:articular surface zone,proliferation zone,fibrous cartilage zone and calcified cartilage zone.The proliferative zone of condylar cartilage of beagle is narrow.The anterior and middle cells of the condylar cartilage were stratified obviously,but the posterior cells were not stratified obviously.The anterior and median cell layers of the condylar cartilage of goat were more obvious than those of the other two animals,with small cell spacing arranged in strips and regular structure of each layer.The condylar cartilage of the three animals all contained collagen fibers.The collagenous fibers of the condylar cartilage of beagle were interwoven into a network in the inner and outer direction and in the front and back direction.The collagen fibers of condylar cartilage of small ear pigs in southern yunnan were mainly in the inner and outer direction,interwoven into a network with the anterior and posterior direction.The collagen fibers of condylar cartilage of goat were mainly in the forward and backward direction,interwoven into a web with the inward and outward direction.No elastic fibers were found in the condylar cartilage of beagle dogs.The anterior,middle and posterior portions of the condylar cartilage of diminutive porcine condyle in southern yunnan contain elastic fibers,and the middle portion has the highest content.The anterior,middle and posterior portions of goat condylar cartilage all contained elastic fibers,and there was no significant difference in content.[Conclusions]1.Hard tissue section technology ensures the integrity of the temporomandibular joint structure of large animals.The application of fan-o solid green staining,toluiline blue staining,collagen fiber staining and elastic fiber staining in the temporomandibular joint hard tissue section is conducive to the overall observation of the TMJ tissue structure.1.2.The anatomical structures of the temporomandibular joint of the three large animals are similar,but the morphology of the articular fossa and the condylar cartilage of the articular disc of the beagle are quite different from that of the southern yunnan small ear pig and goat.3.The condyles of the three kinds of animals were spindle type,and the condylar chondrocytes were arranged in layers.The structure rules of each layer were similar to that of human condylar chondrocytes.The condyle cartilage of porcupine and goat in southern yunnan contains elastic fiber.4.The articular discs of the three animals were interwoven into a network by a large number of collagen fibers.5.The temporomandibular joint structure of beagle has the best similarity with that of human temporomandibular joint,which can be used as a model animal for temporomandibular joint osteoarthritis.