The foramen spinosum is a hole located in the greater wing of the sphenoid. It is located posterolateral to the foramen ovale and anterior to the sphenoidal spine. It allows the passage of the middle meningeal artery, middle meningeal vein and usually the meningeal branch of the mandibular nerve (sometimes it passes through the foramen ovale).
|Anatomical terms of bone|
The foramen spinosum is often used as a landmark in neurosurgery, due to its close relations with other cranial foramina. It was first described by Jakob Benignus Winslow in the 18th century.
The foramen spinosum is a foramen in the sphenoid that connects the middle cranial fossa to the infra temporal fossa. It is located posterolateral to the foramen ovale and anterior to the sphenoidal spine.
The foramen spinosum varies in size and location. The foramen is rarely absent, usually unilaterally, in which case the middle meningeal artery enters the cranial cavity through the foramen ovale. It may be incomplete, which may occur in almost half of the population. Conversely, in a minority of cases (less than 1%), it may also be duplicated, particularly when the middle meningeal artery is also duplicated.
In the newborn, the foramen spinosum is about 2.25 mm long and in adults about 2.56 mm. The width of the foramen extends from 1.05 mm to about 2.1 mm in adults. The average diameter of the foramen spinosum is 2.63 mm in adults.
The earliest perfect ring-shaped formation of the foramen spinosum was observed in the eighth month after birth and the latest seven years after birth in a developmental study of the foramen rotundum, foramen ovale and foramen spinosum. The majority of the foramina in the skull studies were round in shape. The sphenomandibular ligament, derived from the first pharyngeal arch and usually attached to the spine of the sphenoid bone, may be found attached to the rim of the foramen.
Due to its distinctive position, the foramen is used as an anatomical landmark during neurosurgery. As a landmark, the foramen spinosum reveals the positions of other cranial foramina, the mandibular nerve and trigeminal ganglion, foramen ovale, and foramen rotundum. It may also be relevant in achieving haemostasis during trauma surgery.
The foramen spinosum was first described by the Danish anatomist Jakob Benignus Winslow in the 18th century. It is so-named because of its relationship to the spinous process of the greater wing of the sphenoid bone. However, due to incorrectly declining the noun, the literal meaning is "hole full of thorns" (Latin: foramen spinosum). The correct, but unused name would, in fact, be foramen spinae.
- Inner surface of the base of skull, showing cranial foramina
|Wikimedia Commons has media related to Foramen spinosum.|
- Foramina of skull
- "Illustrated Encyclopedia of Human Anatomic Variation: Opus V: Skeletal Systems: Cranium – Sphenoid Bone". Illustrated Encyclopedia of Human Anatomic Variation. Retrieved 2006-04-10.
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- Anatomy photo:22:os-0902 at the SUNY Downstate Medical Center – "Osteology of the Skull: Internal Surface of Skull"
- Anatomy figure: 27:02-03 at Human Anatomy Online, SUNY Downstate Medical Center – "Schematic view of key landmarks of the infratemporal fossa."
- Anatomy of the Skull – 27. Foramen spinosum