This diagnostic image is a focused frontal view of a chest radiograph (X-ray) centered on the mediastinum and right hilar region. The primary finding is an 'air crescent sign' located in the right hilum, indicated by three black arrows. The sign consists of a curvilinear, crescent-shaped lucency (airspace) that partially surrounds a rounded soft-tissue opacity within a cavitary lesion. This radiographic phenomenon typically represents air trapped between a central mass and the wall of a cavity. While commonly associated with invasive pulmonary aspergillosis (Monod sign), the clinical context here demonstrates the sign in the right hilar vessels, characteristic of pneumomediastinum or pulmonary interstitial emphysema. The image highlights key anatomical landmarks including the trachea, vertebral column, and cardiac silhouette, serving as an educational example of identifying subtle gas patterns in thoracic radiology.

This diagnostic image is a posteroanterior (PA) view chest X-ray illustrating a significant abnormality of the cardiac silhouette. A distinct, rounded prominence is visible along the left cardiac border, suggestive of an enlarged pulmonary trunk or a localized mass. A key radiographic feature is the 'crescent sign'—a thin, radiolucent (dark) rim located at the superior aspect of the prominence, indicating air or low-density interface between the lesion and the adjacent lung or vascular structures. The trachea appears midline, and the right lung field shows no gross consolidations, although the right hilar region appears prominent. This visual is characteristic of pulmonary artery dilation or specific cystic lesions (such as a hydatid cyst) and serves as an educational example of the crescent sign in thoracic radiology for medical students and clinicians specializing in pulmonology and radiology.

Antero-posterior (AP) soft tissue neck radiograph of a pediatric patient, presented as side-by-side images (unannotated and annotated) to demonstrate the methodology for calculating the Frontal Ratio (FR) of tracheal narrowing. The radiograph displays the cervical spine, base of the skull, clavicles, and the air-filled tracheal column. The annotated image on the right illustrates the measurement technique for subglottic stenosis: label 'A' marks the narrowest diameter of the subglottic trachea, while label 'B' indicates the reference tracheal width measured at the level of the clavicles. The mathematical relationship is provided as FR = A/B. This diagnostic imaging technique is typically used in the evaluation of upper airway obstruction, such as croup (laryngotracheobronchitis), where the 'steeple sign'—the characteristic tapering of the subglottic airway—is a hallmark finding. This material is designed for radiology and pediatric educational purposes to quantify the degree of airway constriction.

This diagnostic image is a posterior-anterior (PA) chest radiograph. The primary finding is a focal, wedge-shaped area of increased opacity located in the periphery of the right lower lung field, situated just above the diaphragm and abutting the pleura. This radiographic sign, known as a Hampton’s hump, is characterized by its rounded apex pointing toward the hilum and its broad base against the pleural surface, classically indicating pulmonary infarction secondary to pulmonary embolism. The rest of the lung fields appear largely clear with normal lucency and branching pulmonary vasculature. The cardiac silhouette is centrally located and of normal size. Bony structures, including the ribs and clavicles, are intact, and the costophrenic angles are well-visualized. The trachea is midline, and the diaphragmatic contours are sharp, except where the right-sided consolidation overlaps the lateral basal segment. This image serves as a key educational example of a specific radiographic sign associated with vascular pulmonary pathology and is suitable for teaching diagnostic radiology and emergency medicine triage.

This composite educational graphic combines sagittal ultrasonography images and a 3D anatomical reproduction to illustrate a diagnostic protocol for the lateral pharyngeal area. Section A presents a side-by-side comparison of normal (A1) and pathological (A2) anatomy. In the normal scan, the sternocleidomastoid muscle (SCM) is visible superficially, with the pharynx (P) identified via the airway column shadow. In the affected scan (A2), a distinct, hypoechoic abscess collection (AC) is visualized, causing anatomical distortion and deviation of the pharyngeal structures. Section B provides a 3D anatomical model of the head and neck, mapping five key examination zones: (1) carotid bifurcation, (2) submandibular area, (3) submental area, (4) central neck and upper airway, and (5) lateral pharyngeal area. This resource is designed for clinical imaging instruction, demonstrating how point-of-care ultrasound can detect deep neck space infections and localized collections while outlining a systematic scanning protocol for the cervical region.

Contrast-enhanced CT scan of the neck presented in coronal (A) and horizontal/axial (B) views. The images demonstrate a well-defined, heterogeneous solid-cystic mass located in the right lateral neck (Level II/III). In the coronal view, the lesion is indicated by a red arrow, positioned lateral to the carotid sheath and posterior-lateral to the thyroid gland. The axial view confirms the mass's position lateral to the trachea and deep to the sternocleidomastoid muscle. Internal features include areas of low attenuation representing cystic components and hyperdense foci consistent with calcification. There is no evidence of significant tracheal deviation or invasion of the adjacent major cervical vasculature. Bilateral small cervical lymph nodes are also visible. This imaging is characteristic of secondary pathologies such as branchial cleft cysts or metastatic papillary thyroid carcinoma with cystic changes. The educational focus is on identifying regional neck masses, their anatomical relationships to the carotid sheath, and recognizing heterogeneous cystic-solid internal morphology on diagnostic radiology.

Non-contrast computed tomography (CT) of the neck and superior mediastinum presented in axial (a) and coronal (b) views. The images demonstrate a large, well-circumscribed, heterogeneous soft-tissue mass arising from the left thyroid lobe. In the axial view, the mass causes significant mass effect, resulting in marked rightward tracheal deviation and mild luminal compression. The coronal reconstruction highlights the vertical extent of the lesion, approximately 7.2 cm in sagittal height, showing early substernal extension into the superior mediastinum. The mass is positioned anterior to the vertebral column and displaces the left sternocleidomastoid muscle laterally. The imaging is consistent with a large thyroid goiter or neoplasm, such as Hürthle cell carcinoma, requiring assessment for tracheal patency and potential surgical planning. The surrounding vascular structures and cervical musculature are visible, serving as anatomical landmarks for the extent of the pathology.