This
is probably the most important of the skull views. There are several features
which must be checked on this projection: the hypophyseal fossa, both for
pituitary tumours and for the effects of raised intracranial pressure; the
position of the pineal, if calcified; the width of the soft tissue shadow on
the posterior aspect of the nasopharynx and oropharynx, and the posterior walls
of the maxillary antra.
Do not confuse vault fractures with vascular markings
and suture lines. Look for other physiological calcification sites, e.g.
habenular calcification (reverse C-shape), petroclinoid and interclinoid
ligament calcification. The frontal, sphenoid and maxillary air sinuses are
clearly visualized on this projection, as is the pterygopalatine fossa.