Bregma

Bregma
Superior view of the calvarium, bregma located at the intersection of the coronal and sagittal sutures. Coronal Suture Sagittal Suture Lambdoid Suture (Lambda also visible at the intersection of the lambdoid suture by the sagittal suture.)
Details
Precursor	Anterior fontanelle
System	Skeletal system
Identifiers
Latin	bregma
TA98	A02.1.00.016
TA2	418
FMA	264776
Anatomical terminology [edit on Wikidata]

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 superior middle portion of the calvaria.^[1] It is the point where the frontal bone and the two parietal bones meet.^[1]

Development

The bregma is known as the anterior fontanelle during infancy. The anterior fontanelle is membranous and closes in the first 18-36 months of life.^[2]

Clinical significance

Cleidocranial dysostosis

In the birth defect cleidocranial dysostosis, the anterior fontanelle never closes to form the bregma.

Surgical landmark

The bregma is often used as a reference point for stereotactic surgery of the brain.^[3][4] It may be identified by blunt scraping of the surface of the skull and washing to make the meeting point of the sutures clearer.^[3]

Neonatal examination

Examination of an infant includes palpating the anterior fontanelle.^[5] It should be flat, soft, and less than 3.5cm across.^[5] 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 basion).^[6] This is strongly linked to more general growth.^[6] This can be used to assess the general health of a deceased person as part of an archaeological excavation, giving information on the health of a population.^[6]

Etymology

The word "bregma" comes from the Ancient Greek βρέγμα (brégma), meaning the bone directly above the brain.^[7]

References

This article incorporates text in the public domain from page 135 of the 20th edition of Gray's Anatomy (1918)

1. "Skull, Scalp, and Meninges Overview". Imaging in Neurology, Part 1. AMIRSYS. 2016. pp. 288–291. doi:10.1016/B978-0-323-44781-2.50232-1. ISBN 978-0-323-44781-2.
2. Gilroy, Anne M.; MacPherson, Brian R.; Wikenheiser, Jamie C.; Schuenke, Michael; Schulte, Erik; Schumacher, Udo (2020). Atlas of Anatomy. Anne M. Gilroy, Brian R. MacPherson, Jamie C. Wikenheiser, Markus M. Voll, Karl Wesker, Michael Based on: Schünke (4th ed.). New York: Thieme Medical Publishers. ISBN 978-1-68420-203-4. OCLC 1134458436.
3. Carvey, Paul M.; Maag, Terrence J.; Lin, Donghui (1994). "13 - Injection of Biologically Active Substances into the Brain". Methods in Neurosciences. Vol. 21. Elsevier. pp. 214–234. doi:10.1016/B978-0-12-185291-7.50019-9. ISBN 978-0-12-185291-7. ISSN 1043-9471.
4. Harley, Carolyn W.; Shakhawat, Amin M. D.; Quinlan, Meghan A. L.; Carew, Samantha J.; Walling, Sue G.; Yuan, Qi; Martin, Gerard M. (2018). "Chapter 19 - Using Molecular Biology to Address Locus Coeruleus Modulation of Hippocampal Plasticity and Learning: Progress and Pitfalls". Handbook of Behavioral Neuroscience. Vol. 28. Publisher. pp. 349–364. doi:10.1016/B978-0-12-812028-6.00019-7. ISBN 978-0-12-812028-6. ISSN 1569-7339.
5. Carreiro, Jane E. (2009-01-01). "8 - Labor, delivery and birth". An Osteopathic Approach to Children (2nd ed.). Churchill Livingstone. pp. 131–145. doi:10.1016/b978-0-443-06738-9.00008-3. ISBN 978-0-443-06738-9.
6. Nikita, Efthymia (2017-01-01). "6 - Growth Patterns". Osteoarchaeology - A Guide to the Macroscopic Study of Human Skeletal Remains. Academic Press. pp. 243–267. ISBN 978-0-12-804021-8.
7. Liddell & Scott, Greek-English Lexicon

Additional images

• 
  The bregma, human skull.

External links

• lesson1 at The Anatomy Lesson by Wesley Norman (Georgetown University)