Bregma

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The location of the bregma on the human skull.

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Anterior view of skull highlighting the bregma.

Bregma

The bregma is an important anatomical landmark on the superior aspect of the human skull, located at the intersection of the coronal suture and the sagittal suture. It represents the point where the paired parietal bones meet the frontal bone at the midline, and is situated at the apex of the calvaria (skullcap).

Anatomical Location

The bregma lies on the midline of the skull, at the junction between:

• The coronal suture, which separates the frontal bone from the parietal bones
• The sagittal suture, which separates the two parietal bones

This point is found on the top of the skull, approximately near the center of the cranial vault, and can be used as a palpable surface landmark in both clinical and surgical contexts.

Development

In the developing infant skull, the bregma corresponds to the location of the anterior fontanelle — a membranous gap between the cranial bones that allows for flexibility during birth and rapid brain growth.

• The anterior fontanelle is typically diamond-shaped and remains open at birth.
• Ossification of this region generally occurs between 4 and 26 months after birth.
• Once closed, it becomes the bony landmark known as the bregma.

Clinical Significance

The bregma holds diagnostic and procedural importance in various medical fields:

Pediatric Assessment

• The anterior fontanelle is routinely examined in infants.

A sunken fontanelle may indicate dehydration. A bulging fontanelle may suggest increased intracranial pressure or hydrocephalus.

Neurosurgery

• In stereotactic surgery and other neurosurgical procedures, the bregma serves as a reference point for orienting instruments and for mapping brain coordinates.

Congenital Disorders

• In conditions such as cleidocranial dysostosis, ossification of the anterior fontanelle is delayed or absent, resulting in a persistent open bregma.
• Craniosynostosis may alter the morphology or closure timing of sutures at or near the bregma.

Etymology

The word bregma is derived from the Greek term βρέγμα (brégma), meaning “top of the head” or “crown.”

See Also

• Fontanelle
• Lambda (anatomy)
• Skull sutures
• Cranial landmarks
• Cranial vault
• Anatomical terms of location

External Links

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

• Radiopaedia: Bregma
• NCBI: Anatomy, Bregma

Gray's Anatomy

• Gray's Anatomy Contents
• Gray's Anatomy Subject Index
• About Classic Gray's Anatomy
• Glossary of anatomy terms

Anatomy atlases (external)

[1] - Anatomy Atlases

Adapted from the Classic Grays Anatomy of the Human Body 1918 edition (public domain)