Paranasal Sinus
Sinus is an air-filled space commutating with the nasal cavity within the bone of the face and skull. It forms developmentally through the excavation of by air-filled sacs from the nasal cavity. The process starts parentally and continues trough the course of the organism’s lifetime. This sinus is joined to nasal cavity via the small orifices known as ostia.
Malignancies of this sinus comprise about 0.2 percent of all malignancies. Approximately 80 percent of these malignancies arise in maxillary sinus. It is not only sinus within the skull, mastoid cells in mastoid bone around the middle ear is also type of sinus. This sinus also occurs in many animals including crocodilians, non-avian dinosaurs, birds and mammals.
Dural Venous Sinus
This sinus has venous channels that can be found between the layers of dura mater in the brain. The sinus receives blood from external and internal veins of the brain and the cerebrospinal fluid from subarachnoid space. The walls of this sinus consist of dura mater lined with the endothelium and a specific layer of the flattened cells found in blood vessels.
This type has numerous other sinus such as the inferior sagittal sinus, straight sinus, superior sagittal sinus, occipital sinus and the transverse sinuses, sigmoid sinuses as well as the superior petrosal sinus and inferior petrosal sinus.
Coronary Sinus
This sinus is a collection of veins joined together to from large vessel which collect blood from the myocardium of the heart. The sinus opens into auricle between the inferior vena cava and auriculo-venticular opening.
It is also situated in the right atrium and runs diagonally in groove between the ventricle and left atrium on posterior surface of the heart. The wall of this sinus is partly muscular and at its junction with great coronary vein is somewhat furnished and constructed with valve consisting of 2 unequal segments.