This medical anatomical diagram displays the human skull in two views, focusing on the paranasal sinuses and internal cranial structures. View (a) is an anterior (frontal) perspective of the skull with semi-transparent overlays illustrating the paranasal sinuses. Labeled structures include the frontal sinuses located superior to the orbits, the ethmoid sinus situated medially between the eyes, the orbital plate of the ethmoid bone forming the medial orbital wall, the ocular cavity (orbit), and the large maxillary sinuses within the maxilla. View (b) provides a mid-sagittal section of the facial and mid-cranial region. It highlights the spatial relationship between the nasal cavity and surrounding structures, including the frontal sinus, the perpendicular plate of the ethmoid bone (part of the nasal septum), and the maxilla. Posteriorly, it shows the sphenoid bone containing the sella turcica, where the pituitary gland is seated. This illustration is designed for medical education regarding craniofacial anatomy, specifically for procedures such as Functional Endoscopic Sinus Surgery (FESS) and maxillofacial osteotomies.

This medical image displays a comparative study of the cranial base dural venous sinuses through an anatomical cadaveric specimen and a corresponding schematic diagram. Panel (a) shows an internal view of a human skull base following calvaria and brain removal. The dural sinuses are highlighted by blue latex dispersion injected via the facial vein, demonstrating venous connections. Panel (b) provides an idealized anatomical illustration of the same structures. Key numbered structures in both panels include: (1) Cavernous sinus, located ventrally and centrally; (2) Superior petrosal sinus, extending posterolaterally along the petrous part of the temporal bone; (3) Sigmoid sinus, following an S-shaped course toward the jugular foramen; and (4) Transverse sinus, positioned most posteriorly within the tentorium cerebelli. Orientation markers indicate ventral (v), left (l), and right (r) directions. This content serves to teach the complex intracranial venous anatomy and the clinical significance of venous anastomoses between the extracranial facial veins and the intracranial dural sinus system, which is relevant for understanding the spread of infections or thrombi.

Anatomical diagram depicting the venous drainage of the human head in a lateral view. The illustration highlights the relationship between intracranial dural sinuses and extracranial veins. Key structures identified include the Sigmoid Sinus (SS), which transitions into the Internal Jugular Vein (IJV) as it descends anteriorly. A significant anatomical feature shown is the Mastoid Emissary Vein (MEV), which provides a valveless communication pathway between the intracranial sigmoid sinus and the extracranial Posterior Auricular Vein (POV). The POV is situated posteriorly to the ear and runs roughly parallel to the upper portion of the IJV. The diagram effectively illustrates the concept of emissary veins as collateral drainage routes and their role in intracranial pressure regulation and potential surgical risk during posterior fossa or mastoid procedures. The focus is on neurovascular anatomy, specifically the communication between the dural venous system and superficial scalp veins.