The sagittal suture, also known as the interparietal suture and the ''sutura interparietalis'', is a dense, fibrous
connective tissue joint between the two
parietal bone
The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is n ...
s of the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
. The term is derived from the
Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
word ''sagitta'', meaning
arrow.
Structure
The sagittal suture is formed from the fibrous
connective tissue joint between the two
parietal bones
The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named ...
of the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
.
It has a varied and irregular shape which arises during development.
The pattern is different between the inside and the outside.
Two
anatomical landmarks are found on the sagittal suture: the
bregma, and the
vertex of the skull. The bregma is formed by the intersection of the sagittal and
coronal suture
The coronal suture is a dense, fibrous connective tissue joint that separates the two parietal bones from the frontal bone of the skull.
Structure
The coronal suture lies between the paired parietal bones and the frontal bone of the skull ...
s. The vertex is the highest point on the skull and is often near the midpoint of the sagittal suture.
Development
At
birth, the bones of the skull do not meet.
The gap that remains, which is approximately 5
mm wide, allows for the
brain
A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as Visual perception, vision. I ...
to continue to grow normally after birth.
The inner parts of the parietal bones fuse before the outer parts.
Clinical significance
If certain bones of the skull grow too fast before birth, then "premature closure" of the sutures may occur.
This can cause
craniosynostosis, which results in skull deformities.
Sagittal craniosynostosis is the most common form.
If the sagittal suture closes early the skull becomes long, narrow, and wedge-shaped, a condition called '
scaphocephaly'.
Society and culture
In
forensic anthropology, the sagittal suture is one method used to date human remains. The suture begins to close at age twenty nine, starting at where it intersects at the
lambdoid suture and working forward. By age thirty five, the suture is completely closed. This means that when inspecting a human skull, if the suture is still open, one can assume an age of less than twenty nine. Conversely, if the suture is completely formed, one can assume an age of greater than thirty five.
History
The term is derived from the Latin word ''sagitta'', meaning ''arrow''. The derivation of this term may be demonstrated by observing how the sagittal suture is notched
posteriorly, like an arrow, by the
lambdoid suture.
The sagittal suture is also known as the 'interparietal suture', the ''sutura interparietalis''.
Additional images
File:Sagittal suture - animation03.gif, Animation. Sagittal suture shown in red.
File:Sagittal suture - animation05.gif, Left and right parietal bone
The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is n ...
.
File:Sobo 1909 47 - sagittal suture.png, Sagittal suture seen from inside.
File:Sobo 1909 105.png, Sagittal suture of a new-born child, seen from above.
File:Sagittal suture.jpg, Sagittal suture of a new-born child.
File:Wormian bones.jpg, Sagittal suture with wormian bones.
References
Bibliography
Sagittal suture, ''Stedman's Medical Dictionary'', 27th ed. (2000).
*Moore, Keith L., and T.V.N. Persaud. ''The Developing Human: Clinically Oriented Embryology'', 7th ed. (2003).
External links
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{{Authority control
Cranial sutures
Human head and neck
Joints
Joints of the head and neck
Skeletal system