Definition

Noun: * Emissary vein: A small vein that connects the venous sinuses within the dura mater (the tough outer membrane of the brain) to veins located outside the skull, allowing blood to drain from the intracranial sinuses to the external venous system.

Usage

• The term is used in anatomical and medical contexts to describe specific vascular structures in the head.
• It is often discussed in relation to neurosurgery, cranial anatomy, or potential pathways for infection.

Examples

• "The surgeon carefully avoided the vena emissaria during the procedure to minimize bleeding."
• "In some individuals, an enlarged vena emissaria can be observed on imaging scans."
• "These venae emissariae serve as important connections between the intracranial and extracranial venous systems."

Advanced Usage

• Clinical Significance: Emissary veins are clinically important because they are valveless. This allows blood to flow in either direction, which can potentially serve as a route for the spread of infection from the scalp (e.g., from a boil) into the cranial cavity, leading to serious conditions like meningitis or intracranial abscess.

Variants and Related Words

• Emissary vein: The more common English term for . The plural is .
• Venae emissariae: The correct Latin plural form of .
• Diploic vein: Another type of vein within the skull bones, but it drains the diploë (the spongy bone layer) and connects to other venous structures, not directly to external veins in the same way as an emissary vein.

Synonyms

• Emissary vein

Related Anatomical Structures

• Venous sinus: The channels within the dura mater that collect venous blood from the brain. Emissary veins drain blood these sinuses.
• Dura mater: The thick, outermost meningeal layer of the brain. The venous sinuses run within the dura, and emissary veins pierce through it.
• Scalp veins: The external veins on the surface of the head to which the emissary veins connect.

Noun

1. one of several connecting veins in the scalp and head that drain blood from sinuses in the dura mater to veins outside the skull