Plain radiography remains the imaging study of choice for most applications in the upper extremity. The upper extremity is divided into three sections: the shoulder, the elbow and forearm, and the wrist and hand. Similar to the shoulder, the most common use of elbow and forearm plain radiography is in the setting of acute trauma. As with the rest of the upper extremity, the major indication for imaging of the wrist and hand is in the setting of acute trauma. It is one of the most difficult areas to differentiate between soft tissue and skeletal injury on history and physical examination alone. Imaging is necessary even with obvious fractures because the extent of the fracture, displacement, angulation, and articular involvement are important to determine if the patient needs closed reduction in the ED or immediate orthopedic referral for possible open reduction and surgical fixation.

Radiographic evaluation of the pelvis and spine often starts with plain radiographs, most commonly ordered after a traumatic injury. Patients with non-traumatic back pain do not routinely need radiographs. Indications for plain films in these patients include age older than 55 years, or back pain lasting longer than 4 weeks. Thoracolumbar radiology is capable of diagnosing fractures of the vertebral bodies, such as burst or compression fractures, or transverse fractures due to distraction injuries. Ligamentous injuries can be identified by widening or rotation of the spinous processes, or by dislocation of one vertebral body relative to another. Osteomyelitis, tumors, and Paget disease may be diagnosed if thoracolumbar involvement is present. In the thoracolumbar spine, a burst fracture may be mistaken for a less serious compression fracture. Computed tomography (CT) of the abdomen and pelvis, performed on many trauma patients, may be more accurate in diagnosing injuries of the thoracolumbar spine.

Ultrasound in resuscitation is a necessary tool for evaluating the emergent and unstable patient presenting to the ED. When compared to plain radiography in the diagnosis of free fluid in the thoracic, cardiac, or abdominal cavities, ultrasound is more accurate and time efficient. Severe hypoxia, hypotension, dyspnea, chest pain, ECG abnormalities, tachyarrhythmias, and high-risk conditions such as malignancy and renal failure are a few of the indications to image cardiothoracic structures and their functioning. Cardiac sonography is considered the gold standard of cardiac diagnostic and functional testing. Transesophageal echocardiography (TEE) holds the advantage over transthoracic echocardiography (TTE) of being able to look at the major pulmonary arteries. Unlike other diagnostic imaging modalities, ultrasound is limited by the operator's ability to perform bedside ultrasound. Ultrasound does not allow the physician to distinguish fluid type such as blood and urine, or to evaluate the retroperitoneum.

The elderly have some indications for plain film radiography that are specifically determined by their age group. Imaging of the pelvis is most commonly prompted by pain and/or trauma. In addition to identification of fractures, emergency physicians should look for neoplastic lesions and degenerative changes of the hip joints or sacroiliac joints. Rheumatologic conditions are increasingly common with age. Plain radiology in the evaluation of non bony abdominal pathology has the same limitations in the elderly as it does for other adults, with the consequence that CT is often the imaging modality of choice. Most of the limitations of plain radiography in the elderly are the same as those for adults. Radiographs are limited by the patient's ability to cooperate with the exam. This chapter presents clinical images depicting radiographic findings and pathology that clinicians should be familiar with in the elderly patient.

EDs each year with potential cervical spine (C-spine) injury, prompting approximately 800,000 C-spine radiographs. C-spine or neck radiographs are often useful in evaluating non-traumatic conditions commonly presenting to the ED. C-spine injuries are present in only 2% to 6% of blunt trauma victims and in even fewer non-traumatic ED patients, but the potential for catastrophic outcomes of missed C-spine injuries has led to a high index of suspicion by emergency physicians. C-spine injury is relatively uncommon in the pediatric population; however, rates of mortality and neurological damage are alarmingly high. The pitfall of pediatric C-spine radiography lies in the condition known as spinal cord injury without radiographic abnormality. A growing body of evidence and an increasing amount of authorities are now advocating a shift to computed tomography (CT)-based screening of blunt trauma victims for C-spine injury. CT has been shown to be up to 100% sensitive in multiple studies.

Lower extremity injuries are frequently encountered in ED and urgent care settings. Lower extremity radiography is useful for the diagnosis of fractures and dislocations of the hip, knee, foot, and ankle, as well as demonstrating pathology of the femur, tibia, and fibula. Plain radiography is helpful in evaluating fractures of the lower extremity bones, as well as masses and malignancies, including pathological fractures. Information obtained from plain radiographs may be limited by several factors. Information obtained from plain radiographs may be limited by several factors such as quality of the technique employed. Penetration of the image and proper patient positioning are crucial to obtaining useful images. As with any radiographic imaging, one must have sufficient knowledge of the normal anatomy to be able to recognize pathology. This includes the ability to distinguish normal variants from true pathology.

Plain extremity radiographs are indicated in pediatric patients with significant mechanism of injury, pain, limitation of use or motion, or physical exam evidence of deformity, swelling, or tenderness. The joint above and below the site of injury should be examined, and radiographs of adjacent joints should be obtained when indicated. Pediatric extremities consist of growing bones and ossifications centers, with wide variability in normal-appearing bones based on age. As the physic itself is radiolucent, physeal fractures are not always evident on initial plain radiographs. Minimum views of the extremity should include anteroposterior (AP) and lateral. Negative initial plain radiographs do not exclude a Salter-Harris type 1 physeal fracture. If a pediatric patient has negative films but significant swelling or point tenderness along the physic of a bone, a physeal fracture and splint can be assumed accordingly. The incidence of sprains and dislocations are less common in children than in adults.

Magnetic resonance imaging (MRI) with or without contrast is the study of choice when cerebellar, brainstem, or internal auditory meatus pathology is suspected. Similarly, the yield of computed tomography (CT) brain scans is minimal in patients with syncope or near syncope. Suspected spinal cord compression is best defined by MRI. Traumatic or atraumatic myelopathy should be investigated with emergent MRI. In case of nontraumatic myelopathy, the entire spine must be evaluated by MRI. Ready access to CT and its accurate interpretation is essential in evaluating the patient presenting with a new ischemic neurological deficit. Epidural hematomas are often associated with skull fractures, which should be evaluated with CT bone settings and the plain radiography. Most of epidural hematomas result from laceration of the meningeal arteries and/or dural venous sinuses. MRI is particularly sensitive in demonstrating subacute subdural hematomas because of its inherent soft tissue contrast characteristics and its multiplanar capability.