Comparative Anatomy of the Vomeronasal Organ (VNO) in Sheep (Ovis aries) and Dogs (Canis familiaris) with Simple Reference to its Histological Structure and Vasculature Supply

SUMMARY: The vomeronasal organ (VNO) is located in the anteroinferior part of the nose and the accessory olfactory organ in mammals which is responsible of sense of smell. This study aims to compare the macro and microanatomical structure of the VNO between sheep and dogs. In the current study, we used ten adult slaughtered sheep and ten adult synchronized dogs with different sexes ages 1-2 years. The head of both animals were preserved in 10 % formalin for one week. This study shows in both animals, the VNO occupies the same position in the cavity of the vomer bone and the same relationship in the cranial part of the nasal cavity. Furthermore, the VNO is divided into three parts based on shape that are the rostral, central, and caudal part. The results show the VNO in sheep has a (U) shape and is opened dorsolaterally. It has a small and narrow cavity. It is long 6 cm long, and it has different diameters on its course. In comparison, the vomeronasal organ in dogs is very developed and has a (J) shape. It has a large and long cavity and ends at the fourth molar. Its length is about 10 cm, and it has one diameter on its course. The VNO receives the blood supply from the sphenopalatine and caudal palatine arteries. The present study shows main differences between sheep and dogs VNO in which the structure of vomeronasal bone between the sheep and dog is completely different. The finding will illustrate fundamental differences and provide specific structural differences between the two species.

El órgano vomeronasal (OVN) se encuentra en la parte anteroinferior de la nariz y el órgano olfativo accesorio en los mamíferos es responsable del sentido del olfato. Este estudio tuvo como objetivo comparar la estructura macro y microanatómica del OVN entre ovejas y perros. En el estudio utilizamos diez ovejas adultas y diez perros adultos de diferentes sexos con edades de 1 a 2 años. Las cabezas de ambos animales se conservaron en formol al 10 % durante una semana. Este estudio mostró que en ambos animales, el OVN ocupa la misma posición en la cavidad del hueso vómer y la misma relación en la parte craneal de la cavidad nasal. Según su forma el OVN se divide en tres partes: rostral, central y caudal. Los resultados mostraron que el OVN en las ovejas tiene forma de (U) y está abierto dorsolateralmente. Presenta una cavidad pequeña y estrecha. Además, tiene una longitud de 6 cm y tiene diferentes diámetros en su recorrido. En comparación, el órgano vomeronasal en los perros está muy desarrollado y tiene forma de (J). Presenta una cavidad grande y larga y termina en el cuarto molar. Su longitud es de unos 10 cm y tiene un diámetro distinto en su recorrido. El OVN recibe el suministro de sangre de las arterias esfenopalatina y palatina caudal. El presente estudio muestra las principales diferencias entre el OVN de ovejas y perros en el que la estructura del hueso vomeronasal entre estos dos animales es completamente diferente. Además, los hallazgos ilustran diferencias fundamentales y determinan diferencias estructurales específicas entre las dos especies.

Effect of vomer position following surgically assisted rapid palatal expansion.

PURPOSE: To evaluate the effect of vomer position and prevalence of periodontal dehiscence in patients who underwent surgically assisted rapid palatal expansion (SARPE). The null hypotheses were the following: (1) vomer position in the coronal plane does not influence the degree of skeletal and dental expansion; and (2) there is no association between expansion, periodontal dehiscence and vomer position. METHODS: Twenty-one patients were evaluated before treatment (T0) and immediately after SARPE expansion (T1). After SARPE, the vomer was in the right side in 11 patients and in the left in 10 patients. Skeletal and dental effects were evaluated using CBCT, landmarks and measurements. RESULTS: The maxilla and the nasal cavity expanded asymmetrically. The side containing the vomer had less skeletal expansion but more dental tipping. Dehiscence increased significantly from T0 to T1 and was associated with the amount of skeletal displacement, especially when greater than 3.20 mm. In the first premolars region, there was more than 2 mm of asymmetric expansion observed in 38.5% of the patients. CONCLUSION: The null hypotheses were rejected. The side containing the vomer had less skeletal expansion of the maxilla and nasal cavity but more dental tipping. Dehiscence increased after expansion, but there were no differences between sides.