Locating the Cisterna Magna in a Pig Model: A Surgical Method to Access the Cisterna Magna in a Pig Model for Direct Cannulation

The cisterna magna is an opening in the subarachnoid space, wherein cerebrospinal fluid, or CSF, produced in the ventricular system, drains. This makes the cisterna magna a preferred target for studying CSF circulation.

To access the cisterna magna in a pig model, prep the anesthetized animal in a prone position. Mark the surface anatomy of the animal, starting from the occipital crest towards the thoracic vertebra and each ear base to outline a path for the dermal incisions. Start by making an incision from the occipital crest to the first thoracic vertebra.

Next, incise along the shoulders to further slit the skin. Finally, make incisions from the occipital crest towards the base of each ear. Now, retract the incised skin to expose the underlying neck muscles. Next, dissect the neck muscles and pull them away to reveal the atlas or the first cervical vertebra and the skull base. Next, maneuver the animal's head in an appropriate direction to open the space between the back of the skull and the atlas to access the cisterna magna. 

The cisterna magna can now be directly cannulated for further studies.