The carotid canal is a passage in the petrous part of the

temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...

of the skull through which the

internal carotid artery The internal carotid artery is an artery in the neck which supplies the anterior cerebral artery, anterior and middle cerebral artery, middle cerebral circulation. In human anatomy, the internal and external carotid artery, external carotid ari ...

and its internal carotid (nervous) plexus pass from the neck into (the middle cranial fossa of) the

cranial cavity The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull is also known as the cranium. The cranial cavity is formed by eight cranial bones known as the neurocranium that in human ...

. Observing the trajectory of the canal from exterior to interior, the canal is initially directed vertically before curving anteromedially to reach its internal opening.

Anatomy

The carotid canal has two openings, namely internal and external openings. It is divided in three parts, namely, ascending petrous, transverse petrous, and ascending cavernous parts.

Boundaries

The carotid canal opens into the middle cranial fossa, at the

petrous part of the temporal bone The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three ...

. Anteriorly, it is limited by posterior margin of the

greater wing of sphenoid bone The greater wing of the sphenoid bone, or alisphenoid, is a bony process of the sphenoid bone, positioned in the skull behind each eye. There is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally ...

. Posteromedially, it is limited by basilar part of occipital bone.

Relations

The external opening of carotid canal (Latin: "''apertura externa canalis carotici''") is located upon the inferior aspect of the

. It is situated anterior to the jugular fossa (the two being separated by a ridge upon which the tympanic canaliculus opens inferiorly), and posterolateral to the foramen lacerum. The internal opening of carotid canal (Latin: "''apertura interna canalis carotici''") opens into the middle cranial fossa at the apex of petrous part of temporal bone. It is situated lateral to foramen lacerum. Both internal and external openings of the carotid canal lie anterior to the jugular foramen (which opens into the posterior cranial fossa). The carotid canal is separated from

middle ear The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles (malleus, incus, and stapes), which transfer the vibrations ...

and

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

by a thin plate of bone.

The canal transmits

together with its associated nervous plexus and venous plexus.

Clinical significance

Any skull fractures that damage the carotid canal can put the

at risk.

Angiography Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is perfo ...

can be used to ensure that there is no damage, and to aid in treatment if there is.

Other animals

The carotid canal starts on the inferior surface of the

of the skull at the external opening of the carotid canal (also referred to as the carotid foramen). The canal ascends at first superiorly, and then, making a bend, runs anteromedially. Its internal opening is near the foramen lacerum, above which the internal carotid artery passes on its way anteriorly to the

cavernous sinus 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. Structure The ...

. The carotid canal allows the

to pass into the cranium, as well as the carotid plexus traveling on the artery. The carotid plexus contains sympathetics to the head from the superior cervical ganglion. They have several motor functions: raise the eyelid ( superior tarsal muscle), dilate pupil (pupillary dilator muscle), innervate

sweat glands Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...

of face and

scalp The scalp is the area of the head where head hair grows. It is made up of skin, layers of connective and fibrous tissues, and the membrane of the skull. Anatomically, the scalp is part of the epicranium, a collection of structures covering th ...

and constricts

blood vessels Blood vessels are the tubular structures of a circulatory system that transport blood throughout many animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste an ...

in the head.

Additional images

File:Gray191.png, Horizontal section of nasal and orbital cavities. File:Gray913.png, Coronal section of right temporal bone. File:Slide8qqq.JPG, Carotid canal.

References

External links

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Photo at Winona.edu
{{Authority control Foramina of the skull Skull Bones of the head and neck Human head and neck Otorhinolaryngology