Structure
There are also emissary veins passing through the foramen ovale, jugular foramen, foramen lacerum, and hypoglossal canal.[ citation needed ]
| Emissary veins | |
|---|---|
| Details | |
| Identifiers | |
| Latin | vena emissaria |
| TA98 | A12.0.00.033 A12.3.05.301 |
| TA2 | 4872 |
| FMA | 50790 |
| Anatomical terminology | |
The emissary veins connect the extracranial venous system with the intracranial venous sinuses. They connect the veins outside the cranium to the venous sinuses inside the cranium. They drain from the scalp, through the skull, into the larger meningeal veins [ citation needed ] and dural venous sinuses. They may also connect to diploic veins within the skull. [1]
Emissary veins have an important role in selective cooling of the head. They also serve as routes where infections are carried into the cranial cavity from the extracranial veins to the intracranial veins.
There are several types of emissary veins including the posterior condyloid, mastoid, occipital and parietal emissary veins. [1]
There are also emissary veins passing through the foramen ovale, jugular foramen, foramen lacerum, and hypoglossal canal.[ citation needed ]
Because the emissary veins are valveless, they are an important part in selective brain cooling through bidirectional flow of cooler blood from the evaporating surface of the head. In general, blood flow is from external to internal [2] but the flow can be altered by increased intracranial pressure.
One notable emissary vein, the vein of Vesalius, travels through the sphenoidal emissary foramen inferior to the zygomatic arch, connecting the pterygoid plexus with the cavernous sinus. [3] This is an important route for the spread of infection as cranial nerve VI and the internal carotid pass through the cavernous sinus, with cranial nerves III, IV, V1, and V2 passing alongside the lateral wall of the sinus. Subsequent infection or inflammation in the cavernous sinus can result in septic cavernous sinus thrombosis, with resultant damage to the cranial nerves contained within, as well as further spread of the infection leading to meningitis. [4]
Rupture of an emissary vein can result in a subgaleal hemorrhage, a rare but serious injury most often seen as a complication of vacuum extraction. [5]
Cranial nerves are the nerves that emerge directly from the brain, of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck, including the special senses of vision, taste, smell, and hearing.
The danger triangle of the face consists of the area from the corners of the mouth to the bridge of the nose, including the nose and maxilla. Due to the special nature of the blood supply to the human nose and surrounding area, it is possible for retrograde infection from the nasal area to spread to the brain, causing cavernous sinus thrombosis, meningitis, or brain abscess.
The foramen magnum is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblongata, passes through the foramen magnum as it exits the cranial cavity. Apart from the transmission of the medulla oblongata and its membranes, the foramen magnum transmits the vertebral arteries, the anterior and posterior spinal arteries, the tectorial membranes and alar ligaments. It also transmits the accessory nerve into the skull.
The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation.
In anatomy, the orbit is the cavity or socket/hole of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is 30 millilitres, of which the eye occupies 6.5 ml. The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and duct, the eyelids, medial and lateral palpebral ligaments, cheek ligaments, the suspensory ligament, septum, ciliary ganglion and short ciliary nerves.
The foramen lacerum is a triangular hole in the base of skull. It is located between the sphenoid bone, the apex of the petrous part of the temporal bone, and the basilar part of the occipital bone.
The falx cerebri is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure to separate the cerebral hemispheres. It supports the dural sinuses that provide venous and CSF drainage from the brain. It is attached to the crista galli anteriorly, and blends with the tentorium cerebelli posteriorly.
The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.
In neuroanatomy, the maxillary nerve (V2) is one of the three branches or divisions of the trigeminal nerve, the fifth (CN V) cranial nerve. It comprises the principal functions of sensation from the maxilla, nasal cavity, sinuses, the palate and subsequently that of the mid-face, and is intermediate, both in position and size, between the ophthalmic nerve and the mandibular nerve.
The dural venous sinuses are venous sinuses (channels) found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, and cerebrospinal fluid (CSF) from the subarachnoid space via arachnoid granulations. They mainly empty into the internal jugular vein. Cranial venous sinuses communicate with veins outside the skull through emissary veins. These communications help to keep the pressure of blood in the sinuses constant.
The pterygoid plexus is a fine venous plexus upon and within the lateral pterygoid muscle. It drains by a short maxillary vein.
The trigeminal ganglion is the sensory ganglion of each trigeminal nerve. The trigeminal ganglion is located within the trigeminal cave, a cavity formed by dura mater.
In the base of the skull, in the great wings of the sphenoid bone, medial to the foramen ovale, a small aperture, the sphenoidal emissary foramen, may occasionally be seen opposite the root of the pterygoid process. When present, it opens below near the scaphoid fossa. Vesalius was the first to describe and illustrate this foramen, and is also called the foramen Vesalius. Other names include foramen venosum and canaliculus sphenoidalis.
Cavernous sinus thrombosis (CST) is the formation of a blood clot within the cavernous sinus, a cavity at the base of the brain which drains deoxygenated blood from the brain back to the heart. This is a rare disorder and can be of two types–septic cavernous thrombosis and aseptic cavernous thrombosis. The most common form is septic cavernous sinus thrombosis. The cause is usually from a spreading infection in the nose, sinuses, ears, or teeth. Staphylococcus aureus and Streptococcus are often the associated bacteria.
This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.
Birth trauma refers to damage of the tissues and organs of a newly delivered child, often as a result of physical pressure or trauma during childbirth. It encompasses the long term consequences, often of cognitive nature, of damage to the brain or cranium. Medical study of birth trauma dates to the 16th century, and the morphological consequences of mishandled delivery are described in Renaissance-era medical literature. Birth injury occupies a unique area of concern and study in the medical canon. In ICD-10 "birth trauma" occupied 49 individual codes (P10–Р15).
Sinus pericranii (SP) is a rare disorder characterized by a congenital epicranial venous malformation of the scalp. Treatment of this condition has mainly been recommended for aesthetic reasons and prevention of bleeding.
Guttural pouches are large, auditory-tube diverticula that contain between 300 and 600 ml of air. They are present in odd-toed mammals, some bats, hyraxes, and the American forest mouse. They are paired bilaterally just below the ears, behind the skull and connect to the nasopharynx.
The cerebrospinal venous system (CSVS) consists of the interconnected venous systems of the brain and the spine.
The venous plexus of hypoglossal canal is a small venous plexus surrounding the hypoglossal nerve as it passes through the hypoglossal canal. The plexus connects with the occipital sinus (intercranially), inferior petrosal sinus (intercranially), internal jugular vein (extracranially), condylar vein, and paravertebral venous plexus.
