PRENATAL DEVELOPMENT OF THE CRANIAL MENINGES IN GOATS

摘要

Rrenatal development of the cranial meninges in goats was studied using 52 foetuses with a Crown Rump Length (CRL) ranging from 1.4cm (24 days of gestation) to 41.5cm (full term). The meninges arose as condensation of the neighbouring mesenchyme. Thepia mater started differentiating by 24 days of gestational age and the dura at 40 days. Cartilaginous cranial vault also appeared by 40 days. The arachnoid developed at 48 days of age. The dura was generally thicker in the ventral aspect of brain when compared to the sides and top. Arachnoid, the thinnest of the three, followed the infoldings of the dura. It did not follow me sulci of cerebrum and cerebellum but bridged over them. From the arachnoid, strands of fibres formed a loose reticulum across the subarachnoid space. Pia was highly vascularised and extended deep into the sulci. Depending on the vascularity, thickness of the pia mater varied over different regions and at different ages. In the brainstem and cerebellum, thickness was maximum towards the end of second month. But on the cerebral surface it showed maximum development during fifth month. Pia-arachnoid gave a strong positive reaction for alkaline phosphatase.