The paired bones that form most of the roof and upper sides of the cranial vault, meeting along the sagittal suture
Parietal bones — one on each side, joined at the midline.
Anatomy · Bones
Parietal bone
Paired bones of the skull vault
Skull · cranium
The two parietal bones are large, curved plates that meet at the midline to form most of the roof and upper sides of the skull. Each lies between the frontal bone in front, the occipital bone behind and the temporal bone below. Their inner surfaces are moulded by the brain and by the branches of the middle meningeal artery.
How to spot them
- ▸A pair of large, smooth, convex plates forming the top and upper sides of the cranial vault
- ▸The two bones meet at the midline sagittal suture; each is bordered by coronal, lambdoid and squamous sutures
- ▸A rounded swelling, the eminence, marks the centre of each bone
- ▸Grooves on the inside carry the branches of the middle meningeal artery
What to know
A palpable rounded swelling at the centre of each of these bones marks where ossification began
Parietal bone — the parietal eminence.
Bone at whose corners two named landmarks lie: bregma at the front, and lambda at the back where the sagittal suture meets the lambdoid suture
Parietal bones — bregma (coronal and sagittal sutures) and lambda (sagittal and lambdoid sutures).
A bone bounded by four sutures: the sagittal, coronal, squamous and lambdoid
Parietal bone — sagittal (opposite bone), coronal (frontal), squamous (temporal) and lambdoid (occipital).
Two curved lines on the outer surface of this bone mark the upper limits of the temporalis muscle and its fascia
Parietal bone — the superior and inferior temporal lines.
This bone forms by intramembranous ossification, starting around the eighth week of foetal life
Parietal bone — bone forms directly from mesenchyme, radiating from the parietal eminence.
The Latin word paries, meaning a wall, gives its name to this pair of bones
Parietal bones — the walls of the skull.
Key ideas
- As flat bones formed in membrane, the two bones are still separated at birth by fibrous sutures and fontanelles, allowing the head to compress in the birth canal and the brain to grow.
Quick-fire facts
- •Four borders: sagittal (with the other parietal), frontal (coronal suture), squamous (temporal bone and greater wing of sphenoid) and occipital (lambdoid suture)
- •Bregma is where the coronal and sagittal sutures meet; lambda is where the sagittal and lambdoid sutures meet
- •The anterior fontanelle lies at the bregma and typically closes at around 12 to 18 months
- •The posterior fontanelle lies at the lambda and closes within the first few months
- •A small parietal foramen near the midline, present in some people, transmits an emissary vein from the scalp to the superior sagittal sinus
- •The inner surface bears the sagittal sulcus for the superior sagittal sinus, where the falx cerebri attaches
- •The parietal lobe of the brain lies beneath the parietal bone, from which it takes its name
- •Ossification begins at the parietal eminence around week 8 of foetal development
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Sources
- TeachMeAnatomy — The Parietal Bone
- OpenStax — Anatomy and Physiology 2e, 7.2 The Skull