Frontal bone

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Frontal bone
Position of the frontal bone (highlighted in green).
Animation of the frontal bone
Details
ArticulationsTwelve bones: the sphenoid, the ethmoid, the two parietals, the two nasals, the two maxillae, the two lacrimals, and the two zygomatics
Identifiers
Latinos frontale
MeSHD005624
TA98A02.1.03.001
TA2520
FMA52734
Anatomical terms of bone

In the

orbital cavity holding the eye, and part of the bony part of the nose respectively. The name comes from the Latin word frons (meaning "forehead
").

Structure

The frontal bone is made up of two main parts. These are the

orbital and nasal cavities. Sometimes a third part is included as the nasal part of the frontal bone, and sometimes this is included with the squamous part. The nasal part is between the brow ridges, and ends in a serrated nasal notch that articulates with the nasal bones inferiorly, and with the lacrimal and maxilla bones laterally.[2]

Borders

The border of the squamous part is thick, strongly serrated, bevelled at the expense of the inner table above, where it rests upon the parietal bones, and at the expense of the outer table on either side, where it receives the lateral pressure of those bones; this border is continued below into a triangular, rough surface, which articulates with the great wing of the sphenoid. The posterior borders of the orbital plates are thin and serrated, and articulate with the small wings of the sphenoid. [1]

Development

The frontal bone is presumed to be derived from

neural crest cells.[3]

The frontal bone is

squama
, and backwards to form the orbital plate. The spine is ossified from a pair of secondary centers, on either side of the middle line; similar centers appear in the nasal part and zygomatic processes.

At birth the bone consists of two pieces, separated by the

frontal sinuses begins at the end of the first or beginning of the second year, but may begin at birth. The sinuses are of considerable size by the seventh or eighth year, but do not attain their full proportions until after puberty
.

Other animals

In most

postfrontals, together form the upper margin of the eye sockets, and lie to either side of the frontal bones.[4]

Dinosaurs

The frontal bone is one of the principal paired mid-line bones in dinosaur skulls. This bone is part of the skull roof, which is a set of bones that cover the brain, eyes and nostrils. The frontal makes contact with several other bones in the skull. The anterior part of the bone articulates with the nasal bone and the prefrontal bone. The posterior part of the bone articulates with the postorbital bone and the parietal bone. This bone defines all of part of the upper margin of the orbit.

See also

This article uses anatomical terminology.

References

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

  1. ^ a b Gray's Anatomy (1918)
  2. ISBN 9780702068515
    .
  3. PMID 2197017
    .
  4. ISBN 0-03-910284-X
    .

External links

Wikimedia Commons has media related to Frontal bones.
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