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.[4]
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.[5][6]
Development
Similar to other foramina, the foramen ovale differs in shape and size throughout life. In a study using over 350 skulls, the earliest perfect ring-shaped formation of the foramen ovale was observed in the 7th month of fetal life, and the latest in 3 years after birth.[5]
Clinical significance
The foramen ovale is used as the entry point into the skull when conducting a Percutaneous Rhizotomy using either radio-frequency ablation, balloon compression or glycerol injection. These are performed to treat trigeminal neuralgia. In the procedure, the electrode is introduced through the cheek of an anesthetized patient and radiologically guided into the foramen ovale, with the intention of partially or fully ablating one or more of the divisions (typically the Mandibular) to relieve pain.[7]
This entry point is also used to surgically place local electrodes directly on the surface of the mesial temporal lobe, in order to observe neural activity of patients with suspected focal epilepsy.[8]
History
Etymology
The name "foramen ovale" comes from the Latin "oval hole / window".
^ abcDrake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN978-0-8089-2306-0.
^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. PMID16228954.
^ abYanagi 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. PMID3610040.
^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. PMID6486466.