Anatomy & Organs

Ala major ossis sphenoidalis – structure, function & diseases

Ala major ossis sphenoidalis

The ala major ossis sphenoidalis is the greater wing of the sphenoid bone . What is meant by this are two strong bone plates, the attachment of which is located on the body of the sphenoid bone .

What is the greater wing of the sphenoid?

Two strong bone plates are referred to as the ala major ossis sphenoidalis or alae majores ossis sphenoidales.

Its attachment is on the side of the sphenoid bone (Os sphenoidale). In addition to the large wings of the sphenoid bone, there are also the smaller wings of the sphenoid bone (Alae minores ossis sphenoidales). The posterior portion of the wings of the sphenoid connects with the angle located between the squama ossis temporalis and the petrous bone (pars petrosa ossis temporalis) at the base of the temporal bone .

Anatomy & Structure

The ala major ossis sphenoidalis is part of the sphenoid bone. Both wings of the sphenoid bend concavely in the upper direction of the skull. The posterior segment of the greater wing articulates with the angular segment between the temporal bone and the petrous part of the temporal bone.On the back of the wings of the sphenoid bone there is a prominent bony ridge pointing inferiorly. This is the spina angularis ossis sphenoidalis. The insertion of the sphenomandibular ligament is located on it. The soft palate muscle ( musculus tensor veli palatini ) also has its origin at this point.

The Ala major ossis sphenoidalis is equipped with several surfaces. These are referred to as the superior, lateral, and orbital surfaces. From the intracranial superior surface of the wing of the sphenoid, a major portion of the median fossa (middle cranial fossa) is formed. The concave surface has a multiplicity of indentations. These take up the cerebral convolutions of the temporal lobe . In the medial as well as in the front section is the forming rotundum, a round opening for the maxillary nerve ( Nervus maxillaris ).

Another opening, the foramen ovale, is located on the rear side, which allows passage of the mandibular nerve ( Nervus mandibularis ) and the Arteria meningea accessory. In the middle section of the foramen ovale there is sometimes a foramen vesalii, in which there is a small vein. This extends to the cavernous sinus. The foramen spinosum is located on the posterior side of the wings of the sphenoid bone. It is traversed by the spinous nerve, which forms a branch of the lower jaw nerve, and the middle meningeal artery (Arteria meningea media).

The convex lateral surface of the ala major ossis sphenoidalis is divided into two sections by the crista infratemporalis, a ridge of bone. The temporal or superior part represents a section of the temporal fossa. It also forms the origin of the temporal muscle (musculus temporalis). The infratemporal or inferior portion of the lateral surface is smaller. He participates in the modeling of the infratemporal fossa. Together with the crista infratemporalis, it forms the original surface of the outer wing muscle ( musculus pterygoideus lateralis ).

It perforates through the foramen spinosum and the foramen ovale. In the posterior area is the spina angularis. It represents the origin of the sphenomandibular ligament and soft palate muscle. The smooth, flat orbital surface of the greater sphenoidal wing has a square shape. It is aimed in the front and middle direction. It also marks the posterior portion of the lateral orbital wall. The upper jagged edge of the orbital surface and the frontal bone (os frontale) articulate with each other.

The round lower area ensures the delimitation of the fissura orbitalis inferior. From the middle edge of the orbital surface, the lower lip of the superior orbital fissure is formed. A branch of the lacrimal artery (arteria lacrimalis) is taken from a small notch. Below the middle end section of the orbital fissure is a section of bone that is indented. It represents the posterior wall of the palatine fossa ( pterygopalatine fossa ).

Function & Tasks

As already mentioned, the alae majores ossis sphenoidales form a part of the sphenoid bone. This is considered the central bone of the craniosacral system. Due to its unique anatomical structure, the sphenoid has connections to almost all other bones of the skull. The wing processes of the wings of the sphenoid establish a direct connection to the hard palate. Without a correct alignment of the sphenoid there is a risk of negative effects on the structures of the palate . This in turn has consequences for the jaw and upper teeth.

Another important task of the sphenoid bone is to cool the pituitary gland (pituitary gland), which sits directly on top of it.

Diseases

Misalignments of the sphenoid also affect the greater ossis sphenoidal wing. For example, if there is strong pressure on the ganglia, which are located between the processes of the wings of the sphenoid bone and the palatine bone, this can have negative consequences for the nasal mucous membranes.Like the nasopharynx and the nasal cavities, these are supplied by the ganglia. A typical consequence is a runny nose . In some people, this process causes increased sensitivity to allergies as they breathe in the allergens.

Disorders of the sphenoid bone or wings of the sphenoid can also affect the pituitary gland. Thus, incorrect alignments of the skull affect the cooling of the pituitary gland. Problems of the sphenoid often also have negative consequences for the temporomandibular joint .

The outer sphenoid wing muscles directly influence the mandible. For example, an imbalance in the muscles can affect the lower jaw. If the position of the sphenoid bone is changed, this often causes disturbances in its movements and functions. The main consequences are visual disturbances. In addition, a skull base fracture , which is one of the most common sphenoid bone injuries, can also adversely affect the greater ossis sphenoidal wing.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.