Diagnosis of emergency-critical care conditions requires the same attention to good radiographic technique as routine conditions. Otherwise serious errors can result which may seriously affect outcome. Good technique includes making at least two views, correct positioning and obtaining high quality images with adequate detail and contrast. Fortunately special views are infrequently required for critical care work, i.e., the same projections used in routine radiography of a particular anatomic area are usually adequate.
• Cranial vault fractures
Computed tomography is the most accurate method of evaluation cranial vault fractures but may not be available in most emergency situations. An alternative is to obtain multiple projections of the head in order to visualize at least three tangents of the cranial vault. Lateral, ventrodorsal/dorsoventral and rostral to caudal views provide tangents across three axes of the head (longitudinal, dorsal and transverse) improving the likelihood of identifying a fracture of the calvarium. Most displaced fractures can be seen with this technique. Knowledge of the location of suture lines of the cranial vault is necessary to avoid misinterpretation.
• Atlantoaxial subluxation
Trauma of the axis or atlas and hypoplasia of the dens and can lead to displacement of the axis with respect to the atlas, causing compression of the cervical spinal cord. Radiographic diagnosis is dependent on correct interpretation of the lateral projection with the beam centered on the atlantooccipital region. Chemical restraint is not recommended because of the possibility of worsening the patient's condition due to loss of protective reflexes. In addition, a ventrodorsal projection should not be attempted because extension of the head may aggravate atlantoaxial displacement. Radiographic signs include narrowing of the vertebral canal from dorsal displacement of the axis. There is also increased space between the dorsal lamina of the atlas and the rostral aspect of the spinous process of the axis.
• Fracture or luxation of the thoracic and lumbar vertebral column
As with atlantoaxial subluxation, radiography should begin with lateral projections in patients suspected of having spinal fractures. Close collimation to the vertebral column and use of detail technique are necessary for identifying subtle lesions associated with fracture or luxation. In addition, true lateral positioning with sponges, towels, sandbags, etc. is mandatory to avoid misinterpretation.
• Aggressive versus non aggressive bone lesion-anywhere in the skeleton
Although not immediately life threatening, aggressive bone lesions must be identified in the ER setting. Radiographic differentiation of aggressive versus non aggressive lesions has be extensively described in the literature
• Long bone and pelvic fractures
Radiographic classification of long bone fractures is relatively straight forward providing two projections are obtained. In the manus and pes, additional oblique projections are often necessary to avoid missing undisplaced fractures. This especially pertains to the digits where and additional "fan" view should always be made. This is a mediolateral projection with tape applied to digits 2 and 5. Mild tension is applied to place the digits in a "fan" orientation.
• Signs of compound fracture
o Gas in soft tissues near fracture
o Defect in skin