The femoral head notch.

A notch-like defect at the vertex of the proximal femoral ossification center is a normal variant in children. This has often been mistaken for Legg-Perthes disease. This sharply defined defect is distinct from the irregular epiphyseal ossification patterns common in other areas.

The lateral chest film and pneumoperitoneum.

The erect posteroanterior chest film has long been considered the most sensitive for the detection of intraperitoneal free air. A review of 21 cases of pneumoperitoneum showed three with air present on the lateral but not on the frontal chest radiograph. An explanation for this finding is proposed. We believe that careful evaluation of the lateral chest radiograph for pneumoperitoneum will be helpful in certain cases.

The upper femoral notch.

A notch-like defect in the cortex of the medial side of the femoral neck is described in asymptomatic children. Its appearance is similar to the metaphyseal cortical defects seen in other locations as normal variants.

Supine subpulmonary pneumothorax.

Intrapleural air often assumes a subpulmonary position in the recumbent patient even in the absence of underlying pulmonary disease. The margins of the collapsed lung may be difficult or impossible to detect, and a poorly defined basilar hyperlucency may be the only clue present. Additional helpful findings include depression and clear visualization of the diaphragm anteriorly (anterior costophrenic sulcus) creating a "double" appearance to the diaphragm, an unusually distinct cardiac apex, and pericardial fat tags. These signs should help alert the viewer to the correct diagnosis of pneumothorax.

Pulmonary lesions due to Dirofilaria immitis (dog heartworm). Report of four cases with radiologic findings.

Chest radiographs of 4 patients with Dirofilaria immitis (dog heartworm) revealed solitary, small, peripheral, noncalcified nodular lesions. The pulmonary lesions were apparently produced secondary to lodging of the parasite in peripheral pulmonary vessels. None of the patients had symptoms referable to the heartworm lesions. Needle aspiration in 2 patients revealed a nonspecific inflammatory lesion.

Major thoracic dehiscence: radiographic considerations.

Postoperative major thoracic dehiscence is an uncommon but potentially fatal complication which is sometimes difficult to detect clinically. Radiography may provide the initial clue to this abnormality. The wire sutures of sternotomy incisions may break, rotate, or become displaced. Disruption of posterolateral incisions is manifested by an increase in the distance between adjacent ribs. Air-fluid collections may be visible in the soft tissues of the chest wall.

Intestinal perforation in adults due to ingested opaque foreign bodies.

Accidental foreign body ingestion occasionally occurs in adults and is especially likely in those wearing dentures. While most foreign bodies pass readily through the gastrointestinal tract, complications such perforation, abscess, obstruction and hemorrhage occasionally occur. Radiography may be of help in detecting and localizing these foreign bodies and in determining complications caused by them.