Foramen ovale (skull)
Encyclopedia
At the base of the skull
the foramen ovale (Latin: oval window) is one of the larger of the several holes (the foramina) that transmit nerves through the skull. The foramen ovale is situated in the posterior part of the sphenoid bone
, posterolateral to the foramen rotundum
.
The contents of this foramen neatly form the mnemonic 'OVALE' (otic ganglion, V3, accessory meningeal artery, lesser petrosal nerve, emissary veins)
In a study conducted on 100 skulls, the foramen ovale was divided into 2 or 3 components in 4.5% of the cases. The borders of the foramen in some skulls were also irregular and rough. This may suggest, based on radiological images, the presence of morbid changes, which might be the sole anatomical variation in the foramina ovale of humans. (Reymond et al.)
In newborn, the foramen ovale is about 3.85 mm and in the adults about 7.2 mm in length. The average maximal length is about 7.48 mm and its average minimal length is 4.17 mm in the adult. The width extends from 1.81 mm in the newborn to 3.7 mm in adults.
Base of the skull
The base of skull is the most inferior area of the skull, composed of the endocranium and lower parts of the skull roof.-Bones:*Ethmoid bone*Sphenoid bone*Occipital bone*Frontal bone*Parietal bone*Temporal bone**Petrous portion of the temporal bone...
the foramen ovale (Latin: oval window) is one of the larger of the several holes (the foramina) that transmit nerves through the skull. The foramen ovale is situated in the posterior part of the sphenoid bone
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
, posterolateral to the foramen rotundum
Foramen rotundum
The foramen rotundum is a circular hole in the sphenoid bone that connects the middle cranial fossa and the pterygopalatine fossa.-Structure:...
.
Contents
Several nerves, arteries and veins pass through the foramen ovale. They are as follows:- Mandibular nerveMandibular nerveThe mandibular nerve is the largest of the three branches of the trigeminal nerve.-Roots:It is made up of two roots:* a large sensory root proceeding from the inferior angle of the trigeminal ganglion....
(the third branch (V3) of the trigeminal nerveTrigeminal nerveThe trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
) - Accessory meningeal artery (small meningeal or parvidural branch, sometimes derived from the middle meningeal arteryMiddle meningeal arteryThe middle meningeal artery is typically the third branch of the first part of the maxillary artery, one of the two terminal branches of the external carotid artery...
) - Lesser petrosal nerveLesser petrosal nerveThe lesser petrosal nerve consists of parasympathetic fibres. It leaves the tympanic plexus to synapse in the otic ganglion, and eventually provide parasympathetic innervation to the parotid gland....
of (CN IX) (note: the lesser superficial petrosal nerve sometimes passes through a special canal (canaliculus innominatus of Arnold), situated medial to the foramen spinosumForamen spinosumThe foramen spinosum is one of several foramina located in the base of the skull, on the sphenoid bone, situated lateral to the foramen ovale, in a posterior angle.-Contents:It permits the passage of certain arteries, veins and/or other structures:...
) - Emissary veinsEmissary veinsThe emissary veins are valveless veins which normally drain external veins of the skull into the dural venous sinuses. However, because they are valveless, pus can flow into the skull through them as well, making them a possible route for transmission of extracranial infection to get into the...
(from the cavernous sinusCavernous sinusThe cavernous sinus , within the human head, is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.-Contents:...
to the pterygoid plexusPterygoid plexusThe pterygoid plexus is a venous plexus of considerable size, and is situated between the temporalis muscle and lateral pterygoid muscle, and partly between the two pterygoid muscles.-Tributaries received:...
)
- The otic ganglionOtic ganglionThe otic ganglion is a small, oval shaped, flattened parasympathetic ganglion of a reddish-gray color, located immediately below the foramen ovale in the infratemporal fossa. It gives innervation to the parotid gland for salivation....
is situated directly under the foramen, but is also transmitted through the foramen ovale.
The contents of this foramen neatly form the mnemonic 'OVALE' (otic ganglion, V3, accessory meningeal artery, lesser petrosal nerve, emissary veins)
Morphology and morphometry
Similar to other foramina, the foramen ovale differs in shape and size throughout the natural life. The earliest perfect ring-shaped formation of the foramen ovale was observed in the 7th fetal month and the latest in 3 years after birth, in a study using over 350 skulls.In a study conducted on 100 skulls, the foramen ovale was divided into 2 or 3 components in 4.5% of the cases. The borders of the foramen in some skulls were also irregular and rough. This may suggest, based on radiological images, the presence of morbid changes, which might be the sole anatomical variation in the foramina ovale of humans. (Reymond et al.)
In newborn, the foramen ovale is about 3.85 mm and in the adults about 7.2 mm in length. The average maximal length is about 7.48 mm and its average minimal length is 4.17 mm in the adult. The width extends from 1.81 mm in the newborn to 3.7 mm in adults.