Foramen spinosum
Encyclopedia
The 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.
through the foramen ovale.
The foramen spinosum and ovale may be continuous, and the foramen spinosum may be duplicated. Wood-Jones (1931) found the foramen spinosum to be more or less incomplete in approx. 44% of the cases. The foramen spinosum was small or altogether absent in 0.4% of Lindblom's (1936) cases. This is especially true when the middle meningeal artery arises from the ophthalmic artery
(the foramen would be near to empty in that case). In rare cases, early division of the middle meningeal artery into a posterior and anterior division may result in a duplication of the foramen spinosum.
In the newborn, the foramen spinosum is about 2.25 mm and in the adults about 2.56 mm in length. The width of the foramen extends from 1.05 mm to about 2.1 mm in the adults. The average diameter of the foramen spinosum is 2.63 mm in the adult.
The earliest perfect ring-shaped formation of the foramen spinosum was observed in the 8th month after birth and the latest in 7 years after birth in a developmental study on the foramen rotundum
, foramen ovale
and foramen spinosum. The majority of the foramen in the skulls studies was round in shape. Ginsberg et al. (see reference below) observed asymmetry of size in 16% of their patients.
In a study under 123 CT studies, Ginsberg, Pruett, Chen and Elster did not find an inverse relationship between the size of the foramen spinosum and that of the foramen ovale (for instance, a smaller foramen spinosum did not correlate with the size of the foramen ovale).
Foramina of skull
The human skull has numerous holes through which cranial nerves, arteries, veins and other structures pass.-List of foramina and the structures that pass through them:...
located in the base of the skull
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...
, on 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...
, situated lateral to the foramen ovale
Foramen ovale (skull)
At the base of the skull the foramen ovale is one of the larger of the several holes that transmit nerves through the skull. The foramen ovale is situated in the posterior part of the sphenoid bone, posterolateral to the foramen rotundum.-Contents:Several nerves, arteries and veins pass through...
, in a posterior angle.
Contents
It permits the passage of certain arteries, veins and/or other structures:- the parietal trunk of 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...
- a recurrent branch, the nervus spinosusNervus spinosusThe meningeal branch of the mandibular nerve is a branch of the mandibular nerve that supplies the dura mater.-Course:It enters the skull through the foramen spinosum with the middle meningeal artery....
, from the 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 mandibular nerve is 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...
) - the posterior trunk of the middle meningeal vein
Morphology and morphometry
The foramen may be absent (in approx. 2% of the cases), in which case the middle meningeal artery enters the cranial cavityCranial cavity
The cranial cavity, or intracranial space, is the space formed inside the skull. The brain occupies the cranial cavity, which is lined by the meninges and which contains cerebrospinal fluid to cushion blows....
through the foramen ovale.
The foramen spinosum and ovale may be continuous, and the foramen spinosum may be duplicated. Wood-Jones (1931) found the foramen spinosum to be more or less incomplete in approx. 44% of the cases. The foramen spinosum was small or altogether absent in 0.4% of Lindblom's (1936) cases. This is especially true when the middle meningeal artery arises from the ophthalmic artery
Ophthalmic artery
The ophthalmic artery is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the OA supply all the structures in the orbit as well as some structures in the nose, face and meninges...
(the foramen would be near to empty in that case). In rare cases, early division of the middle meningeal artery into a posterior and anterior division may result in a duplication of the foramen spinosum.
In the newborn, the foramen spinosum is about 2.25 mm and in the adults about 2.56 mm in length. The width of the foramen extends from 1.05 mm to about 2.1 mm in the adults. The average diameter of the foramen spinosum is 2.63 mm in the adult.
The earliest perfect ring-shaped formation of the foramen spinosum was observed in the 8th month after birth and the latest in 7 years after birth in a developmental study on 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:...
, foramen ovale
Foramen ovale (skull)
At the base of the skull the foramen ovale is one of the larger of the several holes that transmit nerves through the skull. The foramen ovale is situated in the posterior part of the sphenoid bone, posterolateral to the foramen rotundum.-Contents:Several nerves, arteries and veins pass through...
and foramen spinosum. The majority of the foramen in the skulls studies was round in shape. Ginsberg et al. (see reference below) observed asymmetry of size in 16% of their patients.
In a study under 123 CT studies, Ginsberg, Pruett, Chen and Elster did not find an inverse relationship between the size of the foramen spinosum and that of the foramen ovale (for instance, a smaller foramen spinosum did not correlate with the size of the foramen ovale).