Estudio anatómico del desarrollo de la región cefálica de los odontocetos

Laburpena

The cephalic region of odontocetes was analyzed mainly during fetal development and perinatal stage but also with juveniles and adults. We performed serial tomographies (CT) and resonances (MR) in the head of two fetuses and a newborn, and from one of them we obtained transversal head sections series. Using up to sixteen fetuses, juveniles and adults, we applied the endoscopic technique inside the oral cavity. Teeth eruption time was calculated and salivary glands, masseter muscle and cavity floor were analyzed. Additionally, in the frontal region was described with detail the external nose (nasal opening) and the melon, the nasal vestibule, nasal cavity and nasopharynx using endoscopy, CT, MRI, 3D reconstructions, sections, dissections and compared histology and histopathology. Also, together the eyeball and orbit were analysed underline the absence of infraorbitary border. Regarding the ear and nasopharynx, the pharyngeal diverticulum of the auditory tube was described exhaustively and also the pharynx using endoscopy, MRI, sections, dissections and osteology. The brain was studied superficially, highlighting the ossification of the tentorium of the cerebelum as in domestic cat. Objectives Obtain sequenced cephalic MRI and CT images to compare them with anatomical sections. Study the mucosa of the nasal, oral and pharyngeal cavities using endoscopy. Review anatomic terms wrongly described in the scientific literature and name them following the anatomical veterinary nomenclature. Add three-dimensional reconstructions and dissections. Performing compared anatomical studies between cetaceans and terrestrial mammals. Stablishing anatomical bases that allow be used as reference in future studies of this type and be useful as well to professionals working with cetaceans. Methodology 30 cetaceans and 4 equids were analysed using a dual tomography and a microtomography. MRI were performed with 1.5 Tesla apparatus. The endoscopic explorations were done using a rigid endoscope. The histological sections were stained with Hematoxiline-eosine. Later, they were photographed with a computerized microscope. The 3D reconstructions were analysed with the AMIRA software processing the images obtained from MRI apparatus and the anatomical sections were cut with a band saw. Conclusions 1. Rostral teeth not emerging until end of lactation protects mammary papilla. 2. We confirm the absence of masseter muscle, lymphatic nodules and salivary glands. 3. Fusion between lacrimal bone and zygomatic was observed during fetal period. 4. Temporal process of the zygomatic bone holds the periorbit in the fetus. 5. Melon is part of the external nose from the start of the development. 6. 3D reconstructions confirmed endoscopic observations. 7. Histology analysis confirmed the resemblance of the dolphin and horse nasal mucosa. 8 the pathological findings revealed a hyperkeratosis inside the nasal vestibule. 9. The dolphin nasal cavity should be named as maxillary cavity. 10. The nasal vestibule contains diverticula like those in horse nasal cavity, that working as water reservoirs and protective against external agents 11. The cribriform plate of the ethmoid bone is the last bone ossify in the nasal cavity. 12. No olfactory cells were detected in the nasal cavity during histological analysis. 13. The tongue marginal papilla disappear progressively after lactation. 14. The left pyriform recess was larger than the right, to let swallow large preys in the laryngopharynx. 15. The pharyngeal diverticulum of the auditory tube contain air and a vascular plexus and was compared with the horse pharyngeal diverticulum.