Introduction

Radiography of the head is commonly termed ‘skull radiography’, but because the word ‘skull’ refers to the cranial vault and its bones, ‘skull radiography’ would technically exclude the facial bones, some paranasal sinuses, mandible and temporomandibular joints.

From the mid 1980s onwards there has been a reduction in the number of requests for plain radiography of the head, as computed tomography (CT) and magnetic resonance imaging (MRI) in particular have provided more detailed and useful information (but plain radiography of the facial bones is still regularly requested). These imaging methods now provide information that is either unlikely to be provided by plain radiographic images or is only likely to be demonstrated by it in the later stages of disease processes. There has also been a reduction in the number of projections advocated per examination over the years, in order to reduce radiation dose to patients. Bearing in mind the superiority of MRI and CT, current guidelines do not recommend plain radiography of the cranial vault, even in cases of trauma, unless CT is not available at the time of examination; the exception to this is in cases of non-accidental injury in children.¹

Despite the drop in numbers of requests and projections undertaken, chapters on the head will include a full range of descriptions of projections in order to provide information for regions where CT and MRI are less accessible or inaccessible; in addition, there will still be occasions when two cranial vault projections are required in the trauma situation. Where relevant, a discussion on the suitability of plain radiography versus specialised techniques will be presented throughout the section as each area is covered.

A logical approach to technique

Historically, texts on radiography have presented radiographers and students with information that has included up to approximately 50 projections.^2,3 This has proved daunting for radiographers in training, to say the least, and it is possible that the decline in frequency of use of plain radiography of the head is likely to exacerbate this.

However, if radiography of the head is approached logically it is realised that all projections are based upon a very few basic head positions, or projections, which require modification and variation by use of angulation and differing centring points. Collimation will also vary, according to the area of interest for each projection. With reference to centring points, it will appear that there are as many of these as there are projections. However, on examination of radiographs, it becomes clear that centring points used are logically selected as being in the middle of the area of interest; so it is recommended that, if in doubt, simply ensure the area of interest lies centrally in the collimated field. Realistically, the radiographer need only quote specific centring points when disseminating information to others.

Familiarity with the bony features of the skull and face, and their radiographic appearances, is vital when assessing radiographs for quality. The most important structures for recognition are:

Description of basic projections relies heavily on the use of planes, baselines and surface markings, and the radiographer must be similarly familiar with these (Figs 16.1, 16.2).

Figure 16.1 Surface markings, planes and baselines – 1.

Figure 16.2 Surface markings, planes and baselines – 2.

Basic positions of the head

Related posts:

Film/screen imaging Cranial vault Pelvis and hips Forearm, elbow and humerus Investigations of the genitourinary tract Dental radiography

Stay updated, free articles. Join our Telegram channel

Join