The ala major ossis sphenoidalis is the large wing of the sphenoid bone. This refers to two strong bone plates whose attachment is located on the body of the sphenoid bone.
What is the ala major ossis sphenoidalis?
Two strong bone plates are called the ala major ossis sphenoidalis or alae majores ossis sphenoidales. Their insertion is located laterally on the sphenoid bone (Os sphenoidale). In addition to the greater sphenoidal wings, there are also the lesser sphenoidal wings (alae minores ossis sphenoidales). The posterior segment of the sphenoid wings is associated with the angle located between the temporal bone scale (squama ossis temporalis) and the petrous bone (pars petrosa ossis temporalis) at the base of the temporal bone.
Anatomy and structure
The ala major ossis sphenoidalis is part of the sphenoid bone. Both sphenoid wings curve concavely in the superior direction of the skull. The posterior segment of the ala majores ossis sphenoidales articulates with the angular segment between the temporal bone scale as well as the pars petrosa of the temporal bone. On the posterior aspect of the sphenoid wings, a prominent bony ridge can be seen pointing in the inferior direction. This is the spina angularis ossis sphenoidalis. At it is the attachment of the ligamentum sphenomandibulare. Likewise, the soft palate muscle (Musculus tensor veli palatini) has its origin at this point. The ala major ossis sphenoidalis has several surfaces. These are referred to as the superior, lateral, and orbital surfaces. From the intracranial superior surface of the sphenoid wing, a larger section of the fossa crania media (middle cranial fossa) is formed. The concave surface has a large number of depressions. These accommodate the cerebral convolutions of the temporal lobe. In the medial as well as in the anterior section is the form rotundum, a round opening for the maxillary nerve (Nervus maxillaris). On the posterior side, there is another opening, the foramen ovale, which allows the mandibular nerve and the meningeal access artery to pass through. In the middle section of the foramen ovale, a foramen vesalii is sometimes located, in which a small vein is found. This extends to the cavernous sinus. On the posterior aspect of the sphenoid wings is the foramen spinosum. It is traversed by the spinosal nerve, which forms a branch of the mandibular nerve, and the middle meningeal artery. The convex lateral surface of the ala major ossis sphenoidalis is divided into two sections by the crista infratemporalis, a bony crest. The temporal or superior portion represents a section of the temporal fossa. Furthermore, it forms the origin of the temporalis muscle (Musculus temporalis). The infratemporal or inferior section of the lateral surface is smaller. It participates in the modeling of the infratemporal fossa. Together with the crista infratemporalis it forms the original surface of the external wing muscle (Musculus pterygoideus lateralis). It comes to be pierced by the foramen spinosum as well as the foramen ovale. The spina angularis is located in the posterior region. It represents the origin of the ligamentum sphenomandibulare and the soft palate muscle. A quadrangular shape is exhibited by the smooth, flat orbital surface of the ala major ossis sphenoidalis. It directs in the anterior and middle directions. It also marks the posterior segment of the lateral orbital wall. The upper serrated edge of the orbital surface and the frontal bone (Os frontale) articulate with each other. The round lower area provides the boundary of the fissura orbitalis inferior. From the middle edge of the orbital surface, the lower lip of the fissura orbitalis superior is formed. From a small notch, a branch of the lacrimal artery is received. Under the middle end section of the fissura orbitalis there is a bone section which is indented. It represents the posterior wall of the wing palatal fossa (pterygopalatina).
Function and tasks
As mentioned earlier, the alae majores ossis sphenoidales form a portion of the sphenoid bone. This is considered the central bone of the craniosacral system. The sphenoid bone has connections to almost all other cranial bones due to its unique anatomical structure. The sphenoid wing processes provide a direct connection to the hard palate. Without proper alignment of the sphenoid bone, there is a risk of negative effects on the structures of the palate.This in turn has consequences for the jaw as well as the upper dentition. Another important task of the sphenoid bone is the cooling of the pituitary gland (hypophysis), which sits directly on it.
Diseases
Malpositions of the sphenoid bone also affect the ala major ossis sphenoidalis. If, for example, there is strong pressure on the ganglia, which are located between the processes of the sphenoid wings as well as the palatal bone, this can have negative consequences for the nasal mucous membranes. These are supplied by the ganglia, as are the nasopharynx and the nasal cavities. A typical consequence of this is rhinitis. In some people, this process causes increased sensitivity to allergies, as they inhale the allergens. Disorders of the sphenoid bone or sphenoid wings can also affect the pituitary gland. Thus, improper alignments of the skull affect the cooling of the pituitary gland. Problems of the sphenoid bone also often have negative consequences for the temporomandibular joint. The external sphenoid wing muscles exert a direct influence on the mandible. For example, disturbed balance of the muscles can affect the mandible. If the position of the sphenoid bone is changed, this not infrequently causes disturbances in its movements and functions. The consequences include, first and foremost, visual disturbances. In addition, a skull base fracture, which is one of the most common sphenoid injuries, can also negatively affect the ala major ossis sphenoidalis.
