Educational medical graphic detailing mammary gland anatomy and intraductal (ID) injection methodology. Panel A: Cross-sectional anatomical diagram of the human breast, illustrating ribs, pectoral muscle, and the ductolobular system branching from the nipple opening through fatty connective tissue. Panel B: Histological diagram of a mammary duct, highlighting its bilayered epithelium consisting of inner luminal cells and outer basal/myoepithelial cells, surrounded by macrophages, fibroblasts, and adipocytes. Panel C: Schematic of a murine mammary gland, showing the single efferent duct and branching network within the mammary fat pad. Panel D: Clinical photographs demonstrating a preclinical procedure in a mouse model. The left image shows cannulation of the nipple using a short, blunt-ended needle for intraductal delivery. The right image displays the distribution of blue dye within the ductal system, demonstrating successful infusion of ablative reagents. This figure illustrates the translational approach of using the intraductal route for localized delivery of chemotherapeutics or preventive agents in breast cancer research, such as for BRCA1 mutation carriers.

This composite educational image features corrosion casts of mammary gland anatomy. Figure (a) displays a white glandular cast against a black background, illustrating the complex branching architecture of the ductal system. It shows a primary ascendant milk duct (vertical red marker) transitioning into a wider transversal duct (horizontal blue marker) before arborizing into numerous secondary ducts (white arrowhead) and distal clusters representing terminal alveoli (white arrow). The absence of a prominent teat cistern is a notable anatomical variation. Figure (b) demonstrates a cross-sectional view of resin-perfused ducts within preserved tissue. A primary duct is filled with yellow resin, showing the hollow structure of the teat canal, while an adjacent underdeveloped, blind-ended duct is filled with red resin. These casts are used in anatomical research to study ductal morphology, lobation patterns, and developmental variations such as atrophic or rudimentary ducts, providing insight into physiological milk drainage and the potential pathways for disseminated infections.

This composite educational infographic illustrates the anatomy of the human breast, its cellular structure, and the molecular subtyping of breast cancer. Panel (a) presents an anatomical diagram of the whole breast in cross-section, labeling the pectoral muscle, ribs, adipose tissue, and the functional unit consisting of lobes and mammary ducts. Panel (b) depicts the cellular anatomy of a mammary duct in cross-section, showing the basement membrane, myoepithelium (basal layer), and luminal cells surrounding a central lumen. It highlights pathological progression from carcinoma in situ to invasive carcinoma, demonstrating the breach of basement membrane integrity. Panel (c) is a comparison chart of breast cancer molecular subtypes: Triple Negative, HER2+, Luminal B, Normal-like, and Luminal A. It correlates these subtypes with clinical and pathological features, including percentage of cases, prognosis (gradient from poor/red to good/green), and the expression levels of key biomarkers such as HER2, ER+/PR+, and Ki67. The visual is designed for medical education regarding oncology subtyping and pathophysiology.

This diagnostic anatomical diagram features a breast ultrasound (BUS) image annotated to illustrate the typical layered structure of breast tissue. From superficial to deep, the three primary layers are identified: 1) the Skin and Fat layer, which presents as a relatively hyperechoic (brighter) and heterogeneous area; 2) the Mammary Gland layer, which is delineated by yellow boundary lines and serves as the primary functional tissue; and 3) the Muscle and Rib layer, characterized by lower echogenicity and deeper anatomical positioning. Within the mammary gland layer, a specific focal finding is highlighted: a rounded, hypoechoic (darker) lesion enclosed by a white circular outline. The diagram demonstrates the importance of anatomical localization for lesion detection in clinical sonography, specifically highlighting that breast pathology typically originates within the mammary gland zone. This educational material is designed for radiology students or medical professionals to improve pattern recognition in B-mode breast ultrasonography.

This diagnostic fluorescence image displays two patterns of subcutaneous lymphatic drainage pathways in the human breast, visualized using Indocyanine Green (ICG) fluorescence. Both images demonstrate a high-intensity fluorescent signal at the nipple/subareolar region, representing the injection site. From this origin, linear and slightly tortuous fluorescent streams—indicated by dashed arrows—course towards the axilla (axillary basin). The left image depicts a relatively direct and well-defined pathway, while the right image shows a more diffuse and wider lymphatic channel, potentially illustrating variations in individual anatomy or the merging of multiple lymphatic vessels. The clinical significance of this imagery is the real-time identification of sentinel lymph node drainage pathways, essential for oncological surgical planning and staging. These findings highlight the primary lymphatic flow from the mammary gland towards the axillary lymph nodes, which is a key concept in surgical oncology and breast cancer management.

This diagnostic fluorescence image depicts indocyanine green (ICG) lymphography used for identifying lymphatic drainage patterns in the breast. The visualization shows two primary subcutaneous lymphatic pathways originating from the areolar (nipple) region and extending toward the axilla. In the first panel, a direct pathway is visible (dashed arrow), alongside a secondary curvilinear stream (solid arrow) that traverses the lateral aspects of the mammary parenchyma. The fluorescence identifies a distinct 'lymph node' at the mid-axillary destination (white arrow). The second panel demonstrates the convergence of multiple lymphatic vessels into a complex network, highlighting varying vessel thicknesses and signal intensities. This imaging modality is utilized clinically for sentinel lymph node mapping in breast cancer surgery, allowing real-time transcutaneous guidance and anatomical localization of drainage pathways and Berg's level lymph nodes.

This three-panel composite image displays diagnostic nuclear medicine imaging demonstrating aberrant lymphatic drainage in a patient with ipsilateral breast tumor recurrence (IBTR). Panel A is a planar lymphoscintigraphy image showing a large central area of radiotracer uptake at the injection site. Two secondary foci of uptake are visible: arrow 'a' indicates drainage to the contralateral axilla, and arrow 'b' indicates drainage to the ipsilateral internal mammary chain (IMC). Panels B and C show coronal SPECT/CT fusion images providing anatomical localization for these findings. Panel B demonstrates a 'hot spot' (focal radiotracer uptake) in the right axillary region adjacent to the thoracic wall. Panel C illustrates a 'hot spot' localized to the left internal mammary chain, situated lateral to the sternum. These images illustrate the utility of SPECT/CT in identifying sentinel lymph nodes in non-axillary or contralateral basins, which is clinically significant for staging and surgical planning in recurrent breast cancer cases where normal lymphatic pathways may be surgically disrupted.