TOPOGRAPHY OF THE SUBCOMMISSURAL ORGAN OF THE PIG

The subcommissural organ of pig extended from pineal gland to recessus mesocoelicus on the ventral aspect of posterior commissure and formed partly the roof of third ventricle and cerebral aqueduct. The organ was comprised of two cellular layers i.e. a pseudostratified columnar ciliated ependyma towards the free ventricular surface and a hypendyma adjoining the nervous tissue of the posterior commissure. The subcommissural organ was divided cranio-caudally into four parts viz. pars-supracommissuralis, pa rsprecommissuralis, pars-subcommissuralis and pars-retrocommissuralis in mid sagittal plane. The organ in transverse plane depict ed a horizontal strip of tissue which was continued on either side in the form of ventro-lateral limbs. An abrupt transition of the modified