Foramen ovale (skull)
|Foramen ovale of Sphenoid|
|Sphenoid bone. Upper surface. (foramen ovale labeled at left, third from bottom)|
|Horizontal section of nasal and orbital cavities.|
|Latin||foramen ovale ossis sphenoidalis|
|Gray's||subject #35 150|
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.
Several nerves, arteries and veins pass through the foramen ovale. They are as follows:
- Mandibular nerve (the third branch (V3) of the trigeminal nerve)
- Accessory meningeal artery (small meningeal or parvidural branch, sometimes derived from the middle meningeal artery)
- Lesser petrosal nerve of (CN IX) (note: the lesser superficial petrosal nerve sometimes passes through a special canal (canaliculus innominatus of Arnold), situated medial to the foramen spinosum)
- Emissary veins (from the cavernous sinus to the pterygoid plexus)
- The otic ganglion 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 ovalia 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. 
- Yanagi S (1987). "Developmental studies on the foramen rotundum, foramen ovale and foramen spinosum of the human sphenoid bone". The Hokkaido Journal of Medical Science 62 (3): 485–96. PMID 3610040.
- Reymond J, Charuta A, Wysocki J (2005). "The morphology and morphometry of the foramina of the greater wing of the human sphenoid bone". Folia Morphologica 64 (3): 188–93. PMID 16228954.
- Lang J, Maier R, Schafhauser O (1984). "Postnatal enlargement of the foramina rotundum, ovale et spinosum and their topographical changes". Anatomischer Anzeiger 156 (5): 351–87. PMID 6486466.
- SUNY Labs 22:os-0904
- cranialnerves at The Anatomy Lesson by Wesley Norman (Georgetown University) (IX)
- Roche Lexicon - illustrated navigator, at Elsevier 34257.000-1
- Foramen+ovale at eMedicine Dictionary
- Adult skull as seen from beneath at uiuc.edu