This anatomical diagram provides a lateral and medial perspective of the human right and left lungs, highlighting pulmonary lobar anatomy and surface landmarks. The right lung illustration demonstrates two fissures: the oblique (major) fissure, which runs diagonally, and the horizontal (minor) fissure, which branches anteriorly from the oblique fissure to separate the lung into three lobes (superior, middle, and inferior). The left lung illustration displays a single oblique (major) fissure, dividing it into two lobes (superior and inferior). Key anatomical features labeled include the 'Pleural dome' at the apex of both lungs and the 'Cardiac area'—a distinct indentation on the medial aspect of the left lung where the heart resides. The diagram effectively illustrates the morphological differences between the lungs, specifically the more complex fissural pattern of the right lung compared to the two-lobed structure of the left lung. This visual is designed for medical education regarding respiratory anatomy, thoracic landmarks, and surgical or diagnostic localization.

This clinical photograph shows a gross anatomical specimen of a right human lung, focusing on its lateral aspect. The lung exhibits a deep reddish-purple coloration and a moist, glistening pleural surface, characteristic of a fresh cadaveric or surgically resected specimen. A black arrow identifies an incomplete horizontal fissure. Rather than completely separating the superior lobe from the middle lobe, the fissure appears as a shallow, abbreviated groove that terminates before reaching the anterior border of the lung. This anatomical variation demonstrates partial fusion between the superior and middle lobes. The oblique fissure is also partially visible, separating the inferior lobe from the rest of the lung parenchyma. This image is used in medical education to illustrate normal anatomical variations in lung lobar anatomy and the clinical significance of fissure completeness for procedures such as lobectomies and pulmonary segmentectomies.

This clinical photograph displays a gross anatomical specimen of a human left lung, focusing on the lobar morphology and pleural surface. The primary feature is a well-defined, complete oblique fissure, marked by a black arrow, which extends across the lateral surface to anatomically separate the superior (upper) and inferior (lower) lobes. The lung parenchyma exhibits a mottled appearance with varied coloration: the upper lobe shows lighter pinkish tones interspersed with dark, anthracotic pigment spots typical of carbon particle deposition. In contrast, the lower lobe presents a deeper reddish-purple hue, likely indicating post-mortem congestion or hypostatic changes. The visceral pleura appears smooth and glistening. Small hexagonal outlines of pulmonary lobules are visible on the surface. This specimen serves as an educational reference for normal thoracic anatomy and common anatomical variations in pulmonary fissures, which are clinically significant for surgical resection, bronchoscopic interventions, and the localization of pulmonary pathology.

This anterior-posterior (AP) chest radiograph illustrates a large left-sided pneumothorax and its subsequent management. The left hemithorax exhibits a significant peripheral radiolucent area devoid of lung markings, indicating air within the pleural space. This results in medial retraction of the left lung towards the hilum, with a visible visceral pleural line. In contrast, the right lung remains fully expanded with normal bronchovascular markings reaching the chest wall. A radiopaque small-bore pigtail catheter is visible, inserted through the lateral left chest wall and terminating in a characteristic curled distal loop within the pleural space to facilitate air drainage and lung re-expansion. Radiopaque ECG leads are also present on the chest surface. This image is an educational example of diagnostic radiology in emergency medicine, demonstrating the visual characteristics of a simple pneumothorax and the correct positioning of a percutaneous pigtail catheter for thoracostomy.

Two-panel clinical photograph of a gross pathology specimen illustrating cardiac hypertrophy and valvular changes. Panel A displays the diaphragmatic surface of the heart, showing massive dilatation of the left atrium (LA) and right atrium (RA) relative to the left ventricle (LV) and right ventricle (RV). The atrioventricular sulcus containing the right coronary artery (**) and the posterior interventricular sulcus containing the posterior interventricular branch (*) are visible. Panel B provides internal views of the left and right atria, highlighting bilateral endocardial thickening. Marked arrows indicate surgical sutures on the posterior cusps of the mitral (M) and tricuspid (T) valves from previous valvoplasties. The specimen demonstrates structural remodeling associated with chronic heart failure and restrictive cardiomyopathy, where the atrial chambers appear disproportionately enlarged compared to the ventricles. This image is educational for understanding cardiac gross anatomy, surgical landmarks in valvular repair, and pathological chamber remodeling.

This clinical photograph displays a transverse cross-section (short-axis view) of a human heart specimen at the ventricular level. The specimen illustrates the gross anatomy of both the left and right ventricles. The left ventricular myocardium exhibits mild concentric hypertrophy, characterized by a thickened muscular wall without accompanying cavitary dilation. The myocardium possesses a uniform tan to light brown color and a firm, fibrous texture, showing no visual evidence of acute or chronic myocardial infarction (e.g., discoloration, softening, or white scarring). The endocardial surfaces and trabeculae carneae are clearly visible within the chambers. A thin layer of yellowish epicardial adipose tissue is present on the external surface of the heart. This specimen serves as an educational example of hypertensive or compensatory myocardial changes in the absence of ischemic heart disease.

Educational panel illustrating human cardiac anatomy through gross specimen photography and Computed Tomography (CT). The upper section contains two clinical photographs of a human heart specimen: (a) a frontal view showing the anterior surface, large vessels (aorta and pulmonary artery), and surface musculature, and (b) a posterior view highlighting white circular patches where vessels were prepared and the darker diaphragmatic surface. The lower section features three axial CT slices demonstrating the heart's internal architecture across different planes: (c) at the ventricular level, showing the thicker left ventricular wall compared to the right; (d) a mid-level slice capturing the spatial transition between atria and ventricles; and (e) a superior slice focusing on the atrial chambers. The CT images utilize contrast-enhancing materials (lead oxide and gelatin) to delineate the endocardial borders and myocardial thickness, serving as a primary dataset for 3D anatomical reconstruction and fiber orientation modeling in cardiovascular research.

This diagnostic image is a 3D volume-rendered reconstruction of a computed tomography angiogram (CTA) of the chest, focusing on the thoracic aorta and its major branches. The aortic arch is clearly visualized, showing the origin of the great vessels. The brachiocephalic trunk and the left common carotid artery appear patent with normal contrast opacification. However, there is a significant vascular pathology at the origin of the left subclavian artery, labeled with 'A'. At this site, there is an abrupt termination of contrast enhancement, indicating a complete proximal occlusion of the left subclavian artery. The distal segment of the artery is not visualized via primary antegrade flow. The image also depicts the pulmonary arterial tree and smaller branching vessels. This finding is clinically significant for diagnosing subclavian steal syndrome or explaining significant inter-arm blood pressure discrepancies. The image serves as a clear educational example of arterial occlusion and the utility of 3D vascular reconstruction in identifying atherosclerotic or thrombotic vascular disease.

This diagnostic image is an arteriography of the aortic arch and supra-aortic trunks. The imaging captures the major arterial branches, including the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. Significant vascular pathology is demonstrated through several key visual features: there is a distinct proximal stenosis of the brachiocephalic trunk shortly after its origin from the aorta. Both the right and left common carotid arteries exhibit a markedly narrowed, 'filiform' (thread-like) appearance as they ascend the neck, indicating significant luminal reduction. Additionally, the right subclavian artery shows a decreased diameter in its distal segment compared to the more robust appearance of the left subclavian artery. These findings are characteristic of Takayasu arteritis, demonstrating the diffuse parietal thickening and resulting stenoses of large-vessel vasculitis. The image serves as a clinical example of large-vessel involvement in systemic inflammatory diseases, illustrating how arterial morphology changes under conditions of chronic wall inflammation and remodeling.

**Imaging Modality:** Digital Subtraction Angiogram (DSA), Aortic Arch Study. **Anatomical Region:** Aortic arch and supra-aortic branches, including the brachiocephalic trunk, left common carotid artery, and left subclavian artery. **Observed Pathology:** * **Brachiocephalic Artery:** Significant high-grade stenosis at the proximal segment (indicated by the white arrow). * **Left Common Carotid Artery:** Complete proximal occlusion with no distal contrast opacification (indicated by the solid black arrow). * **Left Subclavian Artery:** Complete proximal occlusion at the origin from the aortic arch (indicated by the dashed white arrow). **Characteristic Visual Features:** The image demonstrates a pigtail catheter positioned in the ascending aorta. There is a profound lack of normal contrast runoff into the primary arch vessels. The only remaining patent pathway for cerebral perfusion is via the severely stenosed right-sided brachiocephalic circulation. **Clinical Context:** These findings are characteristic of advanced aortoarteritis (such as Takayasu arteritis) or severe multi-vessel atherosclerotic disease, resulting in "pulseless" clinical presentation and critical cephalic ischemia. **Diagnostic Features:** Multi-vessel proximal occlusion/stenosis involving the great vessels of the aortic arch, visualized in a Left Anterior Oblique (LAO) cranially angulated projection.

This clinical photograph shows a diaphragmatic (inferior) view of a human heart specimen. The image is presented in a side-by-side comparison format: the left panel displays the original gross specimen, while the right panel includes red annotations highlighting key anatomical landmarks. The cardiac surface exhibits a mottled reddish-brown myocardium with visible yellow epicardial adipose tissue concentrated along the sulci. The annotations demonstrate a 'T-shaped' intersection of major grooves: a horizontal red line identifies the coronary sulcus (atrioventricular groove), and a perpendicular vertical red line identifies the posterior interventricular sulcus. These landmarks delineate the boundaries between the atria and ventricles, and between the left and right ventricles, respectively. The educational focus is on the spatial orientation of cardiac surface anatomy and the identification of major coronary pathways as they appear from an inferior perspective.

This diagnostic image is a 3D multi-slice computed tomography (MSCT) reconstruction of the heart, focusing on the cardiac venous anatomy and a cardiac resynchronization therapy (CRT) lead placement. The visualization highlights the coronary venous sinus, which extends across the posterior aspect of the atrioventricular groove. Labeled arrows identify the middle cardiac vein running along the posterior interventricular sulcus and the posterior cardiac vein positioned on the left ventricular wall. A notable clinical feature is the presence of a multipolar left ventricular lead successfully implanted within the posterior cardiac vein. The reconstruction demonstrates the complex anatomical relationships and distal anastomoses between these vessels. This clinical finding is significant for demonstrating a separate venous ostium and the use of the posterior vein as an alternative route for CRT lead placement when traditional cannulation of the coronary sinus is anatomically challenging.

This 3D volume-rendered Computed Tomography Angiography (CTA) image provides a comprehensive visualization of the coronary arterial anatomy. The image displays the major coronary arteries originating from the ascending aorta and coursing over the epicardial surface of the heart. The Left Anterior Descending (LAD) artery is clearly visible descending along the anterior interventricular sulcus, exhibiting multiple diagonal branches. The Left Circumflex (LCX) artery is seen branching from the left main coronary artery and traveling along the left atrioventricular groove. The Right Coronary Artery (RCA) originates from the right coronary sinus and traverses the right atrioventricular groove. All visualized vessels appear patent with smooth luminal contours and no evidence of significant calcified or non-calcified atherosclerotic plaques or stenotic lesions. The myocardium is rendered in a dark, textured brown tone to provide anatomical contrast, and a 40mm scale bar is included for size reference. This diagnostic image is typical for assessing coronary artery disease (CAD) and evaluating coronary anatomy in a clinical setting.

**Imaging Modality:** Computed Tomography (CT) of the chest, axial section, lung window. **Anatomical Region:** Upper thorax at the level of the great vessels and tracheal bifurcation. **Observed Pathology/Anatomic Variant:** Azygos fissure and azygos lobe of the right lung. **Characteristic Visual Features:** * **Azygos Fissure:** A fine, curvilinear high-attenuation line is visible traversing the right upper lung zone. This represents the invaginated mesoazygos, consisting of four layers of pleura (two visceral and two parietal). * **Azygos Vein:** At the medial/anterior termination of the fissure, a small, rounded soft tissue density is noted, representing the azygos vein in an anomalous cephalad position. * **Azygos Lobe:** The accessory fissure separates the superior-medial portion of the right upper lobe, creating an accessory "azygos lobe." **Key Diagnostic Features:** The pathognomonic "teardrop" appearance of the azygos vein at the end of the curvilinear fissure in the right apex. The underlying lung parenchyma within the accessory lobe demonstrates normal attenuation and vascularity. **Clinical Context:** This is a common incidental anatomical variant resulting from the failure of the azygos vein to migrate medially over the lung apex during embryogenesis.

**Imaging Modality:** Computed Tomography (CT) of the chest, axial section, displayed in lung window settings. **Anatomical Region:** Upper thorax at the level of the aortic arch and tracheal bifurcation. **Observed Pathology/Anatomical Variant:** An **azygos lobe** is identified in the apex of the right lung. **Characteristic Visual Features:** - **Azygos Fissure:** A distinct, curvilinear thin line (pleural reflection) is visible traversing the right upper lung field. This fissure is composed of four layers of pleura (two visceral and two parietal). - **Azygos Vein:** At the inferior aspect of the fissure, a focal, teardrop-shaped density is noted, representing the abnormally positioned azygos vein. - **Lung Parenchyma:** The portion of the right lung located medial to the fissure constitutes the accessory azygos lobe. The surrounding lung parenchyma appears otherwise clear without evidence of consolidation or masses. **Key Diagnostic Features:** The pathognomonic finding of a high-riding azygos vein within a displaced pleural fissure, creating an accessory lobe in the right lung apex. This is a common incidental anatomical variant resulting from the failure of the azygos vein to migrate medially over the lung apex during development.

An axial CT scan of the chest at the level of the upper lobes, displaying a common anatomical variant known as an azygos lobe in the right lung. The image shows a characteristic azygos fissure (indicated by a yellow arrow) coursing through the right apical lung parenchyma. This fissure is formed by the anomalous lateral course of the azygos vein, which creates a 'mesoazygos' consisting of four layers of pleura. The resulting azygos lobe is a small, well-defined medial segment of the right upper lobe. The surrounding lung parenchyma appears normally aerated with standard bronchovascular markings. The central airway (trachea) and mediastinal structures are visible and midline. This diagnostic image serves as a classic educational example of a non-pathological thoracic variation that should be distinguished from pulmonary masses or apical scarring during radiological interpretation.