The bregma is the anatomical point on the skull at which the
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 ...
is intersected perpendicularly by the
sagittal suture
The sagittal suture, also known as the interparietal suture and the ''sutura interparietalis'', is a dense, fibrous connective tissue joint between the two parietal bones of the skull. The term is derived from the Latin word ''sagitta'', meanin ...
.
Structure
The bregma is located at the intersection of the
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 ...
and the
sagittal suture
The sagittal suture, also known as the interparietal suture and the ''sutura interparietalis'', is a dense, fibrous connective tissue joint between the two parietal bones of the skull. The term is derived from the Latin word ''sagitta'', meanin ...
on the superior middle portion of the
calvaria.
It is the point where the
frontal bone
The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, par ...
and the two
parietal bone
The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...
s meet.
Development
The bregma is known as the
anterior fontanelle
The anterior fontanelle (bregmatic fontanelle, frontal fontanelle) is the largest fontanelle, and is placed at the junction of the sagittal suture, coronal suture, and frontal suture; it is lozenge-shaped, and measures about 4 cm in its anter ...
during infancy. The anterior fontanelle is membranous and closes in the first 18-36 months of life.
Clinical significance
Cleidocranial dysostosis
In the
birth defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
cleidocranial dysostosis, the
anterior fontanelle
The anterior fontanelle (bregmatic fontanelle, frontal fontanelle) is the largest fontanelle, and is placed at the junction of the sagittal suture, coronal suture, and frontal suture; it is lozenge-shaped, and measures about 4 cm in its anter ...
never closes to form the bregma.
Surgical landmark
The bregma is often used as a reference point for
stereotactic surgery of 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 v ...
.
It may be identified by blunt scraping of the surface of the skull and washing to make the meeting point of the sutures clearer.
Neonatal examination
Examination of an infant includes palpating the
anterior fontanelle
The anterior fontanelle (bregmatic fontanelle, frontal fontanelle) is the largest fontanelle, and is placed at the junction of the sagittal suture, coronal suture, and frontal suture; it is lozenge-shaped, and measures about 4 cm in its anter ...
.
It should be flat, soft, and less than 3.5cm across.
A sunken fontanelle indicates dehydration, whereas a very tense or bulging anterior fontanelle indicates raised intracranial pressure.
Height assessment
Cranial height is defined as the distance between the bregma and the midpoint of the
foramen magnum
The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblon ...
(the basion).
This is strongly linked to more general
growth
Growth may refer to:
Biology
* Auxology, the study of all aspects of human physical growth
* Bacterial growth
* Cell growth
* Growth hormone, a peptide hormone that stimulates growth
* Human development (biology)
* Plant growth
* Secondary growth ...
.
This can be used to assess the general health of a deceased person as part of an
archaeological excavation
In archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is the area being studied. These locations range from one to several areas at a time during a project and can be condu ...
, giving information on the health of a
population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
.
Etymology
The word "bregma" comes from the Ancient Greek βρέγμα (''brégma''), meaning the bone directly above the brain.
[Liddell & Scott, ''Greek-English Lexicon'']
References
Additional images
File:Slide3ROM.JPG, The bregma, human skull.
External links
*
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Human anatomy
Skull