Development of the Sutures, Infraorbital, and Supraorbital Foramina of the Skull in Nigerian Balami, Uda, and Yankasa Breeds of Sheep

Özet

This study aimed to determine the development time of thesutures and foramina of the skull in fetuses of 350 sheep obtainedfrom Northern Nigerian abattoirs. They were separatedinto 7 age groups and their heads collected and processedusing the Alizarin technique. A total of 12 neurocranialsutures were observed in the first and second trimesters; 5and 7 neurocranial and viscerocranial sutures respectively.In the neurocranium, the cornual and interfrontal sutureswere established at 48th–50th day and 51st–53rd days ofgestation respectively, whereas the occipital sutures wereboth identified at 61st–67th days of gestation. The anteriorfontanelle appeared in the second trimester, althoughearlier in Yankasa than in Balami and Uda breeds. However,the posterior fontanelle, interparieto-parietal sutures, andlambdoid sutures were absent. In the viscerocranium, thezygomaticomaxillary and maxilloincisive sutures appearedon the 45th–47th days. The frontonasal sutures were seen onthe 54th–56th days; the lacrimomaxillary sutures, lacrimozygomaticsutures, and frontolacrimal sutures appeared onthe 61st–67th days. In the 3 breeds, the suture formationoccurs at a similar time interval; sutural development isslower in the neurocranium than the viscerocranium; andintrasutural closure of the cornual, interfrontal, frontonasal,zygomaticomaxillary, and maxilloincisive sutures occur asearly as the second trimester.