- Sphenoid bone: structure
- Sphenoid bone: shank
- Sphenoid bone: greater wings
- Sphenoid bone: smaller wings
- Sphenoid bone: winged processes
- Sphenoid bone: functions
- Sphenoid bone: clinical significance
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The sphenoid bone is considered to be the most complex bone in the human body in terms of structure. It belongs to the bones of the skull and connects with many other structures belonging to this group, such as the frontal bone, occipital bone, temporal bones and facial bones. What is the exact structure of the sphenoid bone and what are the functions of this structure?
The sphenoid bone is a relatively small and very important bone in the human body. It is distinguished not only by its complicated structure, but also by the functions it performs. Sometimes - due to the presence of air spaces in the form of sinuses - some authors classify the sphenoid bone among pneumatic bones.
Sphenoid bone: structure
The sphenoid bone resembles a butterfly's wing and the following elements are distinguished within it:
- even larger wings,
- even smaller wings,
- even winged processes.
See what the sphenoid bone looks likeSee the gallery of 5 photos
Sphenoid bone: shank
The shaft of the sphenoid bone has the shape of a cube and it is where the two sphenoid sinuses mentioned above are located. Within the upper surface of the shaft there is a Turkish saddle, which in turn houses the fossa of the pituitary gland. At the back, the Turkish saddle limits the back of the saddle, while on its sides there are rear sloping processes.
Where the shaft of the sphenoid bone meets the occipital bone, a structure called the slope is formed. The saddle tubercle is located anteriorly from the Turkish saddle, and the visual precrossing furrow, which ends with the visual canal, is even more forward to the front. The most advanced is the ethmoid spine - through it, the sphenoid bone connects with the ethmoid bone.
The lateral surfaces of the shaft of the sphenoid bone are where the carotid fissure is present. The front surface of the shaft has a wedge ridge on both sides of which the sphenoid pinions are located. These structures delimit the openings of the sphenoid sinuses. The wedge beak is located on the lower surface of the shaft.
Sphenoid bone: greater wings
Four parts are distinguished within larger wings:
- and jaw.
Their orbital surface is separated from the smaller wing by the upper orbital fissure, while they are separated from the orbital surface of the maxilla by the lower orbital fissure.
Larger wings have three holes:
- oval hole,
- round hole
- and the spike hole.
Sphenoid bone: smaller wings
The beginning of the smaller wings are two legs, covering the visual canal. The posterior edge of each wing forms an anterior sloping process. The smaller wings of the sphenoid bone have two surfaces: outer and inner.
Sphenoid bone: winged processes
Each of the two winged processes departs from the lateral part of the sphenoid bone and consists of a medial and lateral lamina. The medial lamina ends with a wing hook.
Next to this plaque there is a vaginal process with a palatal-labial furrow - along with the sphenoid process of the palatine bone, this structure forms the palatal-vaginal canal.
The place where the above-mentioned laminae connects is important: there is a wing-palatal furrow, and towards the rear from the junction of the laminae there is a wing fossa.
The winged processes are pierced by the wing canals - the structures that connect the base of the skull to the pterygo-palatal fossa.
Sphenoid bone: functions
The sphenoid bone is a place through which or next to which extremely important structures of the human body run - we are talking here about numerous nerves or blood vessels.
For example, the optic nerve runs in the superior orbital fissure, the maxillary nerve runs through the round foramen, and the mandibular nerve runs through the oval foramen.
The sphenoid bone also attaches to most of the muscles involved in chewing food.
Sphenoid bone: clinical significance
Changes in the shape of the sphenoid bone, especially the Turkish saddle and the pituitary fossa, are clinically significant. They can be caused by such serious diseases as pituitary tumors or an aneurysm of the internal carotid artery.
Relevant information can also be obtained by analyzing the structure of the Turkish saddle ridge - its decalcification may be a consequence of an increase in intracranial pressure.
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