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Platybasia; Specialty: Neurosurgical, orthopedic: Symptoms: Platybasia is characterised by abnormal flattening of the skull base as defined as a base of skull angle over 143º.In the absence of neural compression, pain at the back of the skull and upper part of the neck is the most common symptom.
Basilar invagination is invagination (infolding) of the base of the skull that occurs when the top of the C2 vertebra migrates upward. It can cause narrowing of the foramen magnum (the opening in the skull where the spinal cord passes through to the brain). It also may press on the lower brainstem. [1]
The basilar part of the occipital bone (also basioccipital) extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. In the young skull, this area is rough and uneven, and is joined to the body of the sphenoid by a plate of cartilage.
Potentially life-threatening complications, all of which become more common in more severe OI, include: tearing of the major arteries, such as the aorta; [1]: 333 [11] pulmonary valve insufficiency secondary to distortion of the ribcage; [1]: 335–341 [12] and basilar invagination. [13]: 106–107
Several indirect measurements on CT can be used to assess ligamentous integrity at the craniocervical junction. The Wackenheim line, a straight line extending along the posterior margin of the clivus through the dens, should not intersect the dens on plain film, with violation of this relationship raising concern for basilar invagination.
In tunicates, invagination is the first mechanism that takes place during gastrulation. The four largest endoderm cells induce the invagination process in the tunicates. Invagination consists of the internal movements of a sheet of cells (the endoderm) based on changes in their shape.
It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit . Its shape somewhat resembles that of a butterfly , bat or wasp with its wings extended.
The cytostome is located on the anterior end of the cell close to a structure known as the flagellar pocket. The flagellar pocket is also an invagination in the cell and also serves as a site of endocytosis. The opening of the cytostome is approximately level with the opening of the flagellar pocket. [3] Ciliophora is a phylum of protozoa. The ...