24.32: Veins of the Head and Neck
The blood drainage from the head and neck is primarily managed by three pairs of veins: the external jugular, internal jugular, and vertebral veins. The external jugular veins drain superficial scalp and face structures, passing over the sternocleidomastoid muscles to empty into the subclavian veins.
On the other hand, the vertebral veins, unlike their arterial counterparts, are not primarily responsible for brain drainage. Instead, they drain the cervical vertebrae, spinal cord, and some small neck muscles. They run inferiorly through the transverse foramina of the cervical vertebrae before joining the brachiocephalic veins at the neck's root.
The internal jugular veins are the largest of these paired veins and handle the majority of blood drainage from the brain. Originating from the dural venous sinuses, they exit the skull via the jugular foramina and descend alongside the internal carotid arteries. As they journey downward, they receive blood from deep veins of the face and neck. At the base of the neck, each internal jugular vein merges with the subclavian vein on its side to form a brachiocephalic vein. These two brachiocephalic veins then unite to create the superior vena cava.
Additionally, most brain veins drain into the dural venous sinuses, a connected series of enlarged chambers located between the layers of the dura mater. Various sinuses, including the superior sagittal, inferior sagittal, straight sinus, transverse sinuses, and sigmoid sinuses, work together to manage this drainage. The cavernous sinuses also play a role in receiving venous blood from the ophthalmic and facial veins.
