Increased convolutional markings in the vault (copper beaten skull)
Increased convolutional markings may be seen in children.. They are a normal appearance in most cases, especially in children aged 4-8 years at the time of rapid brain growth. Occasionally it is seen in raised intracranial pressure in older children but is a difficult sign to assess. The appearance is due to convolutional markings on the inner skull table.
Fractures are seen as black lines but if the fracture is depressed with overlapping fragments it will appear as a white line. They can usually be differentiated from vessels by the fact that vessels branch smoothly, taper peripherally, and are in known anatomical sites. They are less dark than fractures as one skull table is intact whereas in fractures both skull tables are broken. They can be differentiated from sutures as the latter have irregular outer margins and are in specific sites. Sometimes a suture will be widened after skull trauma and this has the same significance as a fracture.
Fractures of the occipital bone will only show clearly on a Townes view and this should be requested if trauma was to the back of the head.
Basal skull fractures will seldom be seen on plain films due to overlapping bony structures. A lateral skull film following trauma should be taken with a horizontal beam while the patient lies supine. If there is a fracture involving an air sinus or mastoid air cells, air may leak into the cranial cavity producing a fluid level with the cerebro-spinal fluid. Alternatively cerebro-spinal fluid may leak out into a sinus producing a fluid level in the sphenoid or frontal sinus.
Fractures of the nasal sinuses may allow air to pass into the orbits, especially on nose blowing. This causes orbital emphysema with a dark area in the upper orbit just below the supraorbital ridge.
COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING
Computed tomography & magnetic resonance imaging has largely taken over from plain films when available. Computed tomography is done using axial slices at 5-10mm intervals. Coronal sections are used for imaging the pituitary fossa and paranasal sinuses. Intravenous contrast is given in certain cases, especially when metastases are suspected and in brain tumours.
The main indications for CT scanning are: