The petrosquamous suture is a
cranial suture
In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones are ...
between the
petrous portion and the
squama of the
temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears ...
. It forms the
Koerner's septum. The petrous portion forms the medial component of the osseous margin, while the squama forms the lateral component. The anterolateral portion (squama) arises from the
mesenchyme
Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every ...
at 8 weeks of
embryogenesis
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...
while the petromastoid portion develops later from a cartilaginous center at 6 months of fetal development.
In certain people, it can contain an
emissary vein, referred to as the ''petrosquamosal sinus''. Being aware of this anatomic variant with preoperative
CT scanning
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
can be important to prevent bleeding in certain types of
otolaryngological surgeries. Some authors have theorized that a persistent venous sinus reflects an arrest in embryologic development.
See also
*
Petrotympanic fissure
The petrotympanic fissure (also known as the squamotympanic fissure or the glaserian fissure) is a fissure in the temporal bone that runs from the temporomandibular joint to the tympanic cavity.
The mandibular fossa is bounded, in front, by the ...
References
External links
Diagram
Bones of the head and neck
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