Foramen ovale (skull)
Template:Short description Template:Infobox boneTemplate:Not to be confused with The foramen ovale (En: oval window) is a hole in the posterior part of the sphenoid bone, posterolateral to the foramen rotundum. It is one of the larger of the several holes (the foramina) in the skull. It transmits the mandibular nerve, a branch of the trigeminal nerve.
Structure
The foramen ovale is an opening in the greater wing of the sphenoid bone.<ref name=":0">Template:Cite journal</ref> The foramen ovale is one of two cranial foramina in the greater wing, the other being the foramen spinosum.<ref name="GRAYS2005">Template:Cite book</ref> Template:Rp The foramen ovale is posterolateral to the foramen rotundum and anteromedial to the foramen spinosum. Posterior and medial to the foramen is the opening for the carotid canal.<ref name=GRAYS2005 /> Template:Rp
Contents
The following structures pass through foramen ovale:
- [[mandibular nerve|mandibular nerve (CN VTemplate:Sub)]] (a branch of the trigeminal nerve (CN V))<ref name=":0" />
- accessory meningeal artery<ref name=":0" />
- lesser petrosal nerve (a branch of the glossopharyngeal nerve)<ref name=":0" /><ref name="GRAYS2005" />
- an emissary vein connecting the cavernous sinus with the pterygoid plexus<ref name=":0" />
- (occasionally) meningeal branch of the mandibular nerve<ref name=":0222">Template:Cite book</ref>Template:Rp
Variation
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.<ref name="Folia">Template:Cite journal</ref>
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.<ref name="Yanagi">Template:Cite journal</ref><ref name="AnatAnz">Template:Cite journal</ref>
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.<ref name="Yanagi" />
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.<ref>Template:Cite web</ref>
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.<ref>Template:Cite journal</ref>
History
Etymology
The name "foramen ovale" comes from the Latin "oval hole / window".
See also
References
Template:Gray's Template:Reflist
External links
- Template:SUNYAnatomyLabs
- Template:NormanAnatomy (Template:NormanAnatomyFig)
- Template:Cite web
- Adult skull as seen from beneath at uiuc.edu
Template:Skull Template:Foramina of skull Template:Portal bar Template:Authority control