The lesser wings are flattened, triangular in shape, and located above and anterior to the greater wings. Lateral surface Convex in shape, the lateral surface is sectioned into two halves by the infratemporal crest, a sloping ridge. Hence necessitating a sphenoidotomy or surgical opening of the sphenoid sinus. Pathologies Related to Sphenoid Injuries, wounds, and fractures involving the bat bone are usually rare because of its embedded location. The anterior surface of the body presents, in the middle line, a vertical crest, the sphenoidal crest, which articulates with the perpendicular plate of the ethmoid, and forms part of the septum of the nose.
These also link to further pages about related topics such as specific types of fractures, bone diseases and so on. As its naming indicates, it is lodged centrally in the skull crammed together with rest of the seven bones. While the greater wings begin with a broad base at the lateral surface of the sphenoid bone body. The epipterygoids have extended into the wall of the cranium; they are referred to as when separate in mammals, and form the greater wings of the sphenoid when fused into a larger structure. The inferior margin of the orbital surface forms the posterolateral margin of the inferior orbital fissure, while its medial margin forms the inferolateral edge of the superior orbital fissure. In , these various bones are often though not always fused into a single structure; the sphenoid.
Its shape somewhat resembles that of a butterfly or bat with its wings extended. After that, a sphenoidectomy is performed for removing the affected sphenoid section. See notes about, and labelled diagrams of, all on one page. One makes its appearance in each wing between the and about the eighth week. Addressing dysfunction of the sphenoid may not solve all of your problems, but it might just make your life a little better.
He was interested in freeing the bones and sutures of this area in order to positively affect the rest of the body. It is located at the top situated at the preeminences on either end of the posterior clinoid processes. The middle section is the frontal border of the foramen lacerum opening and also forms the posterior boundary for the pterygoid canal opening for the transmission of pterygoid canal artery and nerve. The sphenoid body has six surfaces: superior, posterior, anterior, inferior, and two lateral surfaces. Numerous structures pass through here to reach the bony orbit. The optic nerve and the ophthalmic artery pass through the optical canal that is located along the wings.
Structure and Functions of Sphenoid Bone The sphenoid bone is one of the eight bones that make up the cranium — the superior aspect of the skull that encloses and protects the brain. Source Of Information i ii. The body, which is also called Corpus ossis sphenoidalis, is a cuboid-shape section of the sphenoid bone that is located at the center. By placing my thumbs on your temples and cupping the rest of my hands around the back of the head, I will gently assess the movement of the sphenoid, and use about 5 grams the weight of a nickel of pressure to invite the sphenoid to reorient itself. The upper edge of the orbital surface of the greater wing articulates with the orbital plate of the frontal bone, while the lateral margin articulates with the zygomatic bone.
In front of the spine the circumference presents a concave, serrated edge, bevelled at the expense of the inner table below, and of the outer table above, for articulation with the squamous part of the. In part 2 of this article, we will track what can shift the sphenoid and the possibilities for what is affected by said shift. For example, the scapula is influenced in its alignment and articulations by the humerus. The anterior clinoid process is a cone-like process of the sphenoid on either side of the anterior part of the hypophysial fossa. The lateral surface presents a groove named carotid sulcus generated by the. Wedged in the center of the skull, it looks like a bat or a butterfly, with its wings extended.
A small orifice, the foramen Vesalii, in the middle of the foramen ovale and facing the basilar part of the Pterygoid process serves as a channel for a vein originating from cavernous sinus. A large orifice lies in the front wall of each sphenoidal concha which serves as the passage for sphenoidal sinus that forms the nasal cavity. The projecting medial ends of the lesser wings are termed anterior clinoid processes. Lesser Wings Every lesser wing appears from the anterior part of the body of sphenoid by 2 roots. The pituitary body itself is lodged in a cavity of the sphenoid bone called the pituitary fossa.
Many foramina and fissures are located in the sphenoid that carries nerves and blood vessels of the head and neck, such as the superior orbital fissure with ophthalmic nerve , foramen rotundum with maxillary nerve and foramen ovale with mandibular nerve. The medial plate of the pterygoid process is the medial division of the pterygoid process. Each of these processes comprise a lateral and medial plate. Each except its hamulus is ossified in membrane, and its center probably appears about the ninth or tenth week; the hamulus becomes chondrified during the third month, and almost at once ossifies Fawcett. The paired and often asymmetrical sinuses are small or rudimentary at birth but grow as the skull grows. This flat surface is bordered by a strip which also is the ridgeline for the chiasmatic groove optic groove , a narrow and slanting channel at the front. The most posterior farthest toward the back of the head of these is the sphenoid sinus.
The lateral surface of the greater wing of the sphenoid is convex and divided by a transverse infratemporal crest into a temporal and infratemporal surface. The sphenoidal conchae are each developed from a center that makes its appearance about the fifth month; at birth they consist of small triangular laminae, and it is not until the third year that they become hollowed out and coneshaped; about the fourth year they fuse with the labyrinths of the , and between the ninth and twelfth years they unite with the sphenoid bone. The posterior and anterior clinoid processes enclose the posterior and anterior wall of sella turcica around the pituitary gland respectively. Yet, many of these bones only articulate with one or two other bones. Each lateral surface unites with the greater wing and the pterygoid process of the sphenoid, and has an important feature, the carotid groove.
Right at the backside of this circular opening is another opening-foramen ovale-that acts as a passage for the accessory meningeal artery, mandibular nerve, and occasionally the lesser petrosal nerve. It also forms the lateral border of the optic canal — through which the optic nerve and ophthalmic artery travel to reach the eye. A sphenoidal notch or indentation on both ends of the dorsum sellae serves as the transit for the abducent nerve. The sphenoidal sinuses are present as minute cavities at the time of birth Onodi , but do not attain their full size until after puberty. The mucus secretions produced in the sinuses are continually being swept into the nose by the hair-like structures on the surface of the respiratory membrane lung lining tissues. Out of the 206 bones found in the human body, 22 bones are found in the skull.