The sagittal suture, also known as the interparietal suture and the ''sutura interparietalis'', is a dense, fibrous connective tissue

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...

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 nam ...

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 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 the power of the ...

word ''sagitta'', meaning arrow.

Structure

The sagittal suture is formed from the fibrous connective tissue

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

. 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 The bregma is the anatomical point on the skull at which the coronal suture is intersected perpendicularly by the sagittal suture. Structure The bregma is located at the intersection of the coronal suture and the sagittal suture on the superi ...

, 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. It ...

s. The vertex is the highest point on the skull and is often near the midpoint of the sagittal suture.

Development

birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...

, 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 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 vision. It is the most complex organ in a ve ...

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 Scaphocephaly is a type of cephalic disorder which occurs when there is a premature fusion of the sagittal suture. The sagittal suture joins together the two parietal bones of the skull. Scaphocephaly is the most common of the craniosynostosis con ...

Society and culture

forensic anthropology Forensic anthropology is the application of the anatomical science of anthropology and its various subfields, including forensic archaeology and forensic taphonomy, in a legal setting. A forensic anthropologist can assist in the identification ...

, 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 The lambdoid suture (or lambdoidal suture) is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture. Structure T ...

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 Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

, like an arrow, by the

. 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

. 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 Wormian bones, also known as intrasutural bones or sutural bones, are extra bone pieces that can occur within a suture (joint) in the skull. These are irregular isolated bones that can appear in addition to the usual centres of ossification of the ...

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

* * {{Authority control Cranial sutures Human head and neck Joints Joints of the head and neck Skeletal system